479 WTPZ45 KNHC 072039 TCDEP5 Tropical Storm Simon Discussion Number 2 NWS National Hurricane Center Miami FL EP202026 300 PM CST Wed Oct 07 2026 The system continues to gradually become better organized on satellite imagery with convective banding features becoming more prominent. The latest subjective Dvorak classification from TAFB had a T-number of 2.5, corresponding to an intensity of 35 kt. On this basis, the cyclone is being upgraded to Tropical Storm Simon for this advisory. The storm has developed upper-level anticyclonic outflow over all quadrants of the circulation. ASCAT-B scatterometer data suggested that the center of the cyclone is a little north of the previous track, but the overall motion still appears to be toward the west-northwest, or about 300/7 kt. Simon is likely to continue this general west-northwestward motion for the next day or so, to the south of a weak mid-level ridge. By Friday, the system should turn northwestward and then northward ahead of a 500 mb trough approaching Baja California. In 3-5 days, the cyclone should move generally northward between a mid-level anticyclone and the trough near Baja California. The official forecast track remains on the right side of the guidance envelope, and is close to the Google DeepMind ensemble mean. For the next few days, Simon is expected to remain within an environment of low vertical wind shear and moist low- to mid-level air, while moving over waters of high oceanic heat content. These factors should result in a significant increase in intensity this week, and the system is likely to strengthen into a hurricane, and then into a major hurricane later this week. The NHC intensity forecast is a little above the intensity model consensus, IVCN. Key Messages: 1. Simon is expected to strengthen into a hurricane by Thursday night and approach the west-central coast of Mexico as a major hurricane on Saturday. 2. There is a risk of dangerous wind and storm surge impacts along portions of the west-central coast of Mexico over the weekend and into early next week, and watches could be required by tonight. 3. Heavy rainfall associated with Simon will impact portions of southwestern Mexico later this week and into the weekend. This rainfall may produce life-threatening flooding and mudslides, especially in areas of steep terrain. 4. Swells will affect portions of the southwestern and west-central coast of Mexico through the weekend. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office. FORECAST POSITIONS AND MAX WINDS INIT 07/2100Z 15.5N 101.6W 35 KT 40 MPH 12H 08/0600Z 15.9N 102.7W 45 KT 50 MPH 24H 08/1800Z 16.3N 104.0W 55 KT 65 MPH 36H 09/0600Z 16.6N 104.8W 65 KT 75 MPH 48H 09/1800Z 17.0N 105.1W 75 KT 85 MPH 60H 10/0600Z 17.8N 105.2W 90 KT 105 MPH 72H 10/1800Z 18.9N 105.3W 100 KT 115 MPH 96H 11/1800Z 21.2N 105.6W 80 KT 90 MPH 120H 12/1800Z 23.6N 106.7W 80 KT 90 MPH...INLAND $$ Forecaster Pasch  173 WTPZ45 KNHC 080234 TCDEP5 Tropical Storm Simon Discussion Number 3 NWS National Hurricane Center Miami FL EP202026 900 PM CST Wed Oct 07 2026 Simon has continued to become better organized on satellite imagery over the past 6 hours with a large area of deep convection and improved curved banding. A recent WSF-M microwave pass also shows improved curved banding structure. The latest subjective Dvorak classification from TAFB was 3.0/45 kt, and the initial intensity has been raised to 45 kt accordingly, and this could be conservative. Environmental conditions are quite favorable for significant intensification. The SHIPS Rapid Intensity Index indicates greater than a 50 percent chance of 55 kt of strengthening over the next 48 h. Most of the hurricane regional models, as well as HCCA and GDMI show significant intensification over the next couple of days, and the NHC intensity forecast has been increased accordingly. The NHC forecast now indicates a 110 kt intensity at 60 and 72 h, and this is at the high end of the model suite, in good agreement with the HCCA model. The initial motion is west-northwestward, or 290 degrees at 8 kt. Simon is likely to continue this general west-northwestward motion for the next day or so, to the south of a weak mid-level ridge. By Friday, the system should turn northwestward and then northward ahead of a 500 mb trough approaching Baja California. In 3-5 days, the cyclone should move generally northward between a mid-level anticyclone and the trough near Baja California. The official forecast track has been shifted a bit to the left from 12-60 hours, but is nearly on top of the previous track from days 3 to 5, and is quite similar to the latest HFIP corrected consensus approach (HCCA). The forecast takes Simon toward the coast of west-central Mexico as a dangerous major hurricane in a few days. There is a fair amount of spread in the guidance, and that is important to note because Simon is forecast to be moving nearly parallel to the coastline in about 72 hours when it nears west-central Mexico. A track farther west would keep Simon over water longer, but a track farther east would mean a sooner landfall. Key Messages: 1. Simon is expected to strengthen into a hurricane by Thursday night and approach the west-central coast of Mexico as a major hurricane on Saturday. There is a risk of dangerous wind and storm surge impacts along portions of this coast over the weekend and into early next week, and watches could be required overnight into early Thursday. 2. Heavy rainfall associated with Simon will impact portions of southwestern Mexico later this week and into the weekend. This rainfall may produce life-threatening flooding and mudslides, especially in areas of steep terrain. 3. Swells will affect portions of the southwestern and west-central coast of Mexico through the weekend. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office. FORECAST POSITIONS AND MAX WINDS INIT 08/0300Z 15.6N 102.5W 45 KT 50 MPH 12H 08/1200Z 15.8N 103.6W 60 KT 70 MPH 24H 09/0000Z 16.1N 104.6W 70 KT 80 MPH 36H 09/1200Z 16.4N 105.3W 85 KT 100 MPH 48H 10/0000Z 16.9N 105.5W 100 KT 115 MPH 60H 10/1200Z 17.8N 105.6W 110 KT 125 MPH 72H 11/0000Z 18.9N 105.5W 110 KT 125 MPH 96H 12/0000Z 21.6N 105.8W 90 KT 105 MPH 120H 13/0000Z 24.2N 106.8W 70 KT 80 MPH...INLAND $$ Forecaster Hagen  049 WTPZ45 KNHC 080855 TCDEP5 Tropical Storm Simon Discussion Number 4 NWS National Hurricane Center Miami FL EP202026 300 AM CST Thu Oct 08 2026 This evening's conventional satellite imagery and a recent ASCAT overpass and a 0323 UTC MetOp-SG1 MI indicate that Simon is developing a compact inner core structure. There are also curved bands with -73C to -82C cold cloud tops forming in the west and northeast portions of the cyclone. The TAFB subjective satellite intensity estimate is T3.0/45 kt and a blend of the UW-CIMSS objective estimates (41-47 kt) yield an initial intensity of 45 kt. The shear is low, the atmosphere is moist, and the ocean is warm with high heat content values, all contributing to a high probability of Simon quickly intensifying during the next couple of days. The upper wind pattern is also quite favorable with impressive diffluent easterly flow ventilating the western portion of the cyclone. The latest SHIPS RI Index shows a 63 percent chance of a 55 kt increase in 48 hrs, while the UW-CIMSS AI-RI indicates a similar likelihood of rapid intensification. The official forecast shows Simon becoming a major hurricane in 48 hrs with a peak intensity of 115 kt on Saturday, and this is based on the HFIP-HCCA and slightly above the Google DeepMind ensemble guidance. Simon's initial motion is estimated to be due west, or 270 degrees at 6 kt. This general motion should continue through today while being steered by high pressure north of the cyclone over central Mexico. On Friday, the system should turn west-northwestward to north-northwestward in response to a mid-tropospheric trough approaching Baja California. Toward the end of the period, Simon is expected to move northward ahead of and on the southeastern side of the aforementioned trough and approach the southwestern coast of Mexico over the weekend. The GFS and the ECMWF HiRes global models still show outlier tracks to the left of the NHC forecast but have been trending eastward, aligning more with the better-performing HCCA and Google DeepMind TC ensemble mean aids, which the official forecast leans toward. Simon's 34 kt wind radii were decreased a bit based on a 0403 UTC METOP-B ASCAT pass. Key Messages: 1. Simon is expected to strengthen into a hurricane by early Friday and approach the west-central coast of Mexico as a major hurricane on Saturday. Tropical storm conditions are possible within the tropical storm watch area early Friday. There is also risk of dangerous wind and storm surge impacts along portions of this coast over the weekend and into early next week and additional watches will likely be required for portions of southwestern Mexico. 2. Heavy rainfall associated with Simon will impact portions of southwestern Mexico later this week and into the weekend. This rainfall may produce life-threatening flooding and mudslides, especially in areas of steep terrain. 3. Swells will affect portions of the southwestern and west-central coast of Mexico through the weekend. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office. FORECAST POSITIONS AND MAX WINDS INIT 08/0900Z 15.4N 103.1W 45 KT 50 MPH 12H 08/1800Z 15.4N 104.1W 60 KT 70 MPH 24H 09/0600Z 15.9N 105.1W 75 KT 85 MPH 36H 09/1800Z 16.6N 105.5W 95 KT 110 MPH 48H 10/0600Z 17.4N 105.6W 110 KT 125 MPH 60H 10/1800Z 18.3N 105.4W 115 KT 130 MPH 72H 11/0600Z 19.3N 105.3W 110 KT 125 MPH 96H 12/0600Z 21.8N 105.7W 80 KT 90 MPH 120H 13/0600Z 24.3N 106.1W 55 KT 65 MPH...INLAND $$ Forecaster Roberts  155 WTPZ45 KNHC 081437 TCDEP5 Tropical Storm Simon Discussion Number 5 NWS National Hurricane Center Miami FL EP202026 900 AM CST Thu Oct 08 2026 Simon continues to steadily become better organized. Satellite and microwave images indicate that the storm has a compact inner core and much larger rainbands surrounding it. The outer bands on the northeast side of the circulation are moving across coastal areas of southwestern Mexico, likely bringing heavy rains and gusty winds there. The latest satellite intensity estimates range from 45 to 55 kt, and the initial intensity is set at the high end of the estimates at 55 kt. The tropical storm is moving slowly westward at about 5 kt, steered by a weak mid-level ridge to its north. A continued slow west to west-northwest motion is expected through tonight as that ridge remains in place. However, a sharp turn to the north is forecast on Friday when the ridge weakens and shifts eastward, in response to an approaching mid- to upper-level trough. Although the models generally agree on the large-scale steering pattern evolution, there are very important differences in where and when the system makes that turn. Most of the AI models, including GFSAI, ECAI, and GDMI show the turn occurring well east of the physics-based models. Since the physics-based models have often had a westward bias in this region, the NHC track forecast has been nudged eastward to be in better agreement with the latest AI guidance. This forecast brings the core of the system inland over southwestern and west-central Mexico Saturday night or early Sunday. Environmental conditions are expected to be quite conducive for strengthening, including low wind shear, very warm waters, and high moisture. Based on these favorable conditions and the compact inner core structure, rapid intensification is forecast, and Simon is expected to become a hurricane later today and a very dangerous category 4 hurricane before it reaches the coast of Mexico. This forecast lies near the high end of the guidance, in best agreement with the HCCA model. Based on the latest forecast, the government of Mexico has issued a Hurricane Watch for portions of west-central Mexico. Key Messages: 1. Simon is expected to strengthen to a hurricane later today and approach the west-central coast of Mexico as a major hurricane on Saturday and Saturday night. 2. The risk of life-threatening wind and storm surge impacts is increasing for portions of the west-central coast of Mexico, and a Hurricane Watch is now in effect from Manzanillo to Punta Mita. Preparations to protect life and property should be completed by Saturday. 3. Heavy rainfall associated with Simon will impact portions of southwestern Mexico through this weekend. This rainfall may produce life-threatening flooding and mudslides, especially in areas of steep terrain. 4. Swells will affect portions of the southwestern and west-central coast of Mexico through the weekend. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office. FORECAST POSITIONS AND MAX WINDS INIT 08/1500Z 15.4N 103.3W 55 KT 65 MPH 12H 09/0000Z 15.5N 104.1W 70 KT 80 MPH 24H 09/1200Z 16.1N 104.9W 85 KT 100 MPH 36H 10/0000Z 16.9N 105.1W 100 KT 115 MPH 48H 10/1200Z 17.6N 105.1W 115 KT 130 MPH 60H 11/0000Z 18.7N 105.1W 115 KT 130 MPH 72H 11/1200Z 19.7N 105.1W 115 KT 130 MPH...INLAND 96H 12/1200Z 22.2N 105.6W 65 KT 75 MPH...INLAND 120H 13/1200Z 25.1N 106.0W 30 KT 35 MPH...POST-TROP/INLAND $$ Forecaster Cangialosi  415 WTPZ45 KNHC 082032 TCDEP5 Tropical Storm Simon Discussion Number 6 NWS National Hurricane Center Miami FL EP202026 300 PM CST Thu Oct 08 2026 Simon is almost a hurricane. The storm continues to have a very compact inner core with some signs of an eye becoming apparent in satellite images. There are also numerous spiral bands beyond the inner core region, with the outermost band in the far northeast quadrant still affecting portions of southwestern Mexico. The latest satellite intensity estimates have increased a little from earlier and now range from about 50 to 65 kt. Based on that data, the initial intensity is nudged up to 60 kt. A 17Z ASCAT-C pass was used to adjust the initial wind radii. The tropical storm is moving slowly westward at about 5 kt, steered by a weak mid-level ridge to its north. A turn to the northwest is expected tonight or early Friday, followed by a northward motion later that day when the ridge weakens and shifts eastward, in response to an approaching mid- to upper-level trough. Although the models generally agree on the large-scale steering pattern evolution, there are very important differences in where and when the system makes that turn. There has been a notable shift to the east this cycle, and given the westward bias often seen in the models for this region, the NHC track forecast has been again nudged eastward. It should be noted that the best-performing models of the year so far are east of the official forecast, and additional adjustments might be needed if this trend continues. This forecast brings the core of the system inland over southwestern and west-central Mexico Saturday afternoon or Saturday night. Simon is in near ideal environmental conditions of low wind shear, high moisture, and over very warm waters. The SHIPS model shows more than a 70 percent chance that the system will rapidly intensify over the next 24 hours. In fact, the storm's compact inner core structure makes it even more likely that it will capitalize on the favorable conditions. Therefore, the NHC intensity forecast continues to call for rapid strengthening into a very dangerous category 4 hurricane before Simon reaches the coast of west-central Mexico. This forecast lies near the high end of the guidance, in best agreement with the HCCA model. Based on the new forecast, the government of Mexico has issued a Hurricane Warning for a portion of the coast of southwestern and west-central Mexico. Key Messages: 1. Simon is expected to strengthen to a hurricane by tonight and approach the west-central coast of Mexico as a major hurricane on Saturday. 2. Life-threatening wind and storm surge impacts are expected along a portion of the west-central coast of Mexico, and a Hurricane Warning is now in effect from Punta San Telmo to Playa Perula. Preparations to protect life and property should be completed by late Friday. 3. Heavy rainfall associated with Simon will impact portions of southwestern Mexico through this weekend. This rainfall may produce life-threatening flooding and mudslides, especially in areas of steep terrain. 4. Swells will affect portions of the southwestern and west-central coast of Mexico through the weekend. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office. FORECAST POSITIONS AND MAX WINDS INIT 08/2100Z 15.7N 103.9W 60 KT 70 MPH 12H 09/0600Z 16.1N 104.4W 75 KT 85 MPH 24H 09/1800Z 16.8N 104.9W 95 KT 110 MPH 36H 10/0600Z 17.7N 105.0W 115 KT 130 MPH 48H 10/1800Z 18.8N 104.9W 115 KT 130 MPH 60H 11/0600Z 19.9N 104.9W 65 KT 75 MPH...INLAND 72H 11/1800Z 21.1N 104.8W 35 KT 40 MPH...INLAND 96H 12/1800Z 23.2N 105.0W 25 KT 30 MPH...POST-TROP/INLAND 120H 13/1800Z...DISSIPATED $$ Forecaster Cangialosi  181 WTPZ45 KNHC 090239 TCDEP5 Binary file ep202026.discus.new matches  200 WTPZ45 KNHC 090321 CCA TCDEP5 Hurricane Simon Discussion Number 7...Corrected NWS National Hurricane Center Miami FL EP202026 900 PM CST Thu Oct 08 2026 Corrected malformed non-unicode character in third paragraph. Simon has become a hurricane this evening. The satellite presentation consists of a developing small, intense, central dense overcast with -82C cold cloud tops, and a primary curved band wrapping into the center from the northwest part of the cyclone. The TAFB Dvorak satellite intensity estimate is 65 kt, as well as the initial intensity for this advisory. Simon's wind radii were adjusted based on a 1920 UTC OSCAT-3 overpass. All conducive ocean heat content, dynamic, and thermodynamic environmental contributions indicate that Simon should quickly intensify during the next 24-36 hrs. Subsequently, the SHIPS RI index shows a near 70 percent that the cyclone intensity will increase by 30 kt in 24 hrs. This seems quite reasonable given that Simon's inner core is rather small, indicative of a recent AMSR3 MI pass. Accordingly, the official intensity forecast will continue to predict an RI event on Friday, with Simon becoming a category 4 hurricane while heading toward the coast of west-central Mexico. The NHC intensity forecast is similar to the previous one, is close to the HFIP-HCCA, and now shows a peak intensity of 120 kt on Saturday morning. Simon's initial motion is estimated to be west-northwestward, or 295/5 kt. A turn to the northwest is expected by early Friday. A northward motion is forecast by early Saturday while high pressure over central Mexico weakens and shifts eastward, in response to an amplifying mid-tropospheric trough approaching Baja California. The HiRes global models that have been to the left of the forecast track outliers have trended eastward during the past 24 hours, and now align more with the skilled HCCA and GDMI aids. Therefore, confidence in the forecast track is increasing. The official forecast is slightly to the left of the previous advisory and a little slower to conform to the HCCA model, which includes the Google DeepMind TC ensemble mean. Key Messages: 1. Simon is expected to approach the west-central coast of Mexico as a major hurricane on Saturday. 2. Life-threatening wind and storm surge impacts are expected along a portion of the west-central coast of Mexico, and a Hurricane Warning is in effect from Punta San Telmo to Punta Mita. Preparations to protect life and property should be completed by late Friday. 3. Heavy rainfall associated with Simon will impact portions of southwestern Mexico through this weekend. This rainfall may produce life-threatening flooding and mudslides, especially in areas of steep terrain. 4. Swells will affect portions of the southwestern and west-central coast of Mexico through the weekend. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office. FORECAST POSITIONS AND MAX WINDS INIT 09/0300Z 15.6N 104.6W 65 KT 75 MPH 12H 09/1200Z 16.1N 105.0W 85 KT 100 MPH 24H 10/0000Z 16.9N 105.2W 100 KT 115 MPH 36H 10/1200Z 17.8N 105.3W 120 KT 140 MPH 48H 11/0000Z 19.0N 105.3W 110 KT 125 MPH 60H 11/1200Z 20.4N 105.3W 75 KT 85 MPH...INLAND 72H 12/0000Z 21.6N 105.3W 35 KT 40 MPH...INLAND 96H 13/0000Z 23.3N 105.7W 25 KT 30 MPH...POST-TROP/REMNT LOW 120H 14/0000Z...DISSIPATED $$ Forecaster Roberts  091 WTPZ45 KNHC 090846 TCDEP5 Hurricane Simon Discussion Number 8 NWS National Hurricane Center Miami FL EP202026 300 AM CST Fri Oct 09 2026 Simon has quickly strengthened this morning. A EUMETSAT METOP-B Microwave Humidity Sounder (MHS) image revealed a small banding eye feature, and the IR-BD curve enhancement indicates -83C cold cloud tops associated with a small central dense overcast over the surface center. Water vapor imagery and satellite wind data indicate developing cyclonic outflow above 200 mb. Based on the much improved cloud pattern and the TAFB subjective intensity estimate of T4.5 (77 kt), the initial intensity is increased to 80 kt. Simon's small, intense inner core, favorable environmental conditions, low shear, very warm oceanic temperatures, and high mid-level moisture content all support a rapid intensification event, which appears to be well underway. Further significant strengthening is expected, and the cyclone is forecast to be a very dangerous major hurricane when it approaches the coast of Mexico. The guidance also shows compact Simon quickly weakening and over the high mountainous terrain by early next week. The NHC forecast is once again hedged toward the high end of the guidance, in best agreement with the HFIP-HCCA model. Simon's initial motion is estimated to be northwestward, or 315/4 kt. A northward motion is forecast by early Saturday while high pressure over central Mexico weakens and shifts eastward, in response to an amplifying mid-tropospheric trough approaching Baja California. The HiRes global models (ECM/GFS/CMC/UKM), HAFS hurricane models and the NOAA GEFS AI ensemble mean continue to agree more with Simon approaching the west-central coast of Mexico on Sunday. The HCCA and the Google DeepMind ensemble mean have been somewhat inconsistent during the past 2 cycles, windshield-wipering with a track either inland or just offshore beyond the 48-hour period. Additionally, the along-track forward speeds have also become inconsistent, which has slightly affected the wind impact timing. To minimize these track forecast inconsistencies, the NHC forecast blends the various consensus aids and is nudged to the right of the HCCA and GDM ensemble mean solutions. Key Messages: 1. Simon is expected to approach the west-central coast of Mexico as a major hurricane on Saturday. 2. Life-threatening wind and storm surge impacts are expected along a portion of the west-central coast of Mexico, and a Hurricane Warning is in effect from Punta San Telmo to Punta Mita. Preparations to protect life and property should be completed by late Friday. 3. Heavy rainfall associated with Simon will impact portions of southwestern Mexico through this weekend. This rainfall may produce life-threatening flooding and mudslides, especially in areas of steep terrain. 4. Swells will affect portions of the southwestern and west-central coast of Mexico through the weekend. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office. FORECAST POSITIONS AND MAX WINDS INIT 09/0900Z 15.8N 104.5W 80 KT 90 MPH 12H 09/1800Z 16.1N 104.7W 100 KT 115 MPH 24H 10/0600Z 16.7N 104.9W 120 KT 140 MPH 36H 10/1800Z 17.6N 105.0W 125 KT 145 MPH 48H 11/0600Z 18.6N 105.1W 120 KT 140 MPH 60H 11/1800Z 19.9N 105.3W 110 KT 125 MPH...INLAND 72H 12/0600Z 21.4N 105.4W 80 KT 90 MPH...OVER WATER 96H 13/0600Z 23.7N 106.0W 60 KT 70 MPH...INLAND 120H 14/0600Z 24.9N 106.3W 35 KT 40 MPH...INLAND $$ Forecaster Roberts  073 WTPZ45 KNHC 091447 TCDEP5 Hurricane Simon Discussion Number 9 NWS National Hurricane Center Miami FL EP202026 900 AM CST Fri Oct 09 2026 The intensity of Simon has been hard to diagnose this morning. The most recent TAFB Dvorak fix still supported an intensity of 80 kt at 1200 UTC, while all of the objective techniques from UW-CIMSS are lower. Since that time, a warm spot near the center of Simon's small CDO has recently appeared, which appears to be the early development of an eye. Based on the continued improvement in Simon's satellite appearance, the initial intensity has been increased to 85 kt for the advisory. Over the next 24 hours, continued rapid intensification is expected. The RI probabilistic guidance (both SHIPS and DTOPS) actually decreased this cycle, but the hurricane is located in a low-shear, high-moisture, and high-SST environment that is conducive for explosive deepening. Furthermore, recent microwave imagery, such as an AMSR3 pass just after 08Z suggests the hurricane has a small inner-core, which makes rapid changes in intensity more likely. Therefore, the NHC forecast is in line with the previous one, above most of the guidance and shows Simon becoming a major hurricane later today. Simon's forecast beyond that is extremely difficult, and this is a case where it is important to not focus on the details of NHC's deterministic forecast. Simon will turn northward this weekend, steered between a deep trough to its northwest and a ridge to the east. This track will take the center of Simon very near or over the Mexican states of Colima and Jalisco. If the center of Simon moves over land, it will quickly weaken and could even dissipate, drastically lessening the risk of hurricane-force-winds farther north in Mexico. However, if the core of Simon remains offshore, it will likely continue northward as a hurricane. A majority of the guidance this morning shows Simon remaining just offshore, however most of these models have historically had a west bias in this region. Likewise, ensemble means like GDM or even HCCA can be misleading when some members move inland and dissipate. This results in the mean being computed solely from the surviving, and in this case farther west, members. The NHC forecast therefore remains within, but on the east side of the guidance envelope, and is best characterized as a hedge between the aforementioned possibilities. Key Messages: 1. Simon is expected to approach the west-central coast of Mexico as a major hurricane on Saturday. 2. Catastrophic wind and life-threatening storm surge impacts are likely along a portion of the west-central coast of Mexico, and a Hurricane warning is in effect from Punta San Telmo to Punta Mita. Preparations to protect life and property should be completed by late today. 3. Heavy rainfall associated with Simon will impact portions of southwestern Mexico through this weekend. This rainfall may produce life-threatening flooding and mudslides, especially in areas of steep terrain. 4. Swells will affect portions of the southwestern and west-central coast of Mexico through the weekend. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office. FORECAST POSITIONS AND MAX WINDS INIT 09/1500Z 16.0N 104.7W 85 KT 100 MPH 12H 10/0000Z 16.5N 104.8W 105 KT 120 MPH 24H 10/1200Z 17.2N 104.9W 125 KT 145 MPH 36H 11/0000Z 18.2N 105.0W 125 KT 145 MPH 48H 11/1200Z 19.4N 105.2W 115 KT 130 MPH 60H 12/0000Z 20.7N 105.4W 95 KT 110 MPH...INLAND 72H 12/1200Z 21.9N 105.6W 75 KT 85 MPH...OVER WATER 96H 13/1200Z 23.6N 106.2W 55 KT 65 MPH...INLAND 120H 14/1200Z 24.9N 106.9W 30 KT 35 MPH...POST-TROP/INLAND $$ Forecaster D. ZelinskyNHCN-442849  075 WTPZ45 KNHC 091447 TCDEP5 Hurricane Simon Discussion Number 9 NWS National Hurricane Center Miami FL EP202026 900 AM CST Fri Oct 09 2026 The intensity of Simon has been hard to diagnose this morning. The most recent TAFB Dvorak fix still supported an intensity of 80 kt at 1200 UTC, while all of the objective techniques from UW-CIMSS are lower. Since that time, a warm spot near the center of Simon's small CDO has recently appeared, which appears to be the early development of an eye. Based on the continued improvement in Simon's satellite appearance, the initial intensity has been increased to 85 kt for the advisory. Over the next 24 hours, continued rapid intensification is expected. The RI probabilistic guidance (both SHIPS and DTOPS) actually decreased this cycle, but the hurricane is located in a low-shear, high-moisture, and high-SST environment that is conducive for explosive deepening. Furthermore, recent microwave imagery, such as an AMSR3 pass just after 08Z suggests the hurricane has a small inner-core, which makes rapid changes in intensity more likely. Therefore, the NHC forecast is in line with the previous one, above most of the guidance and shows Simon becoming a major hurricane later today. Simon's forecast beyond that is extremely difficult, and this is a case where it is important to not focus on the details of NHC's deterministic forecast. Simon will turn northward this weekend, steered between a deep trough to its northwest and a ridge to the east. This track will take the center of Simon very near or over the Mexican states of Colima and Jalisco. If the center of Simon moves over land, it will quickly weaken and could even dissipate, drastically lessening the risk of hurricane-force-winds farther north in Mexico. However, if the core of Simon remains offshore, it will likely continue northward as a hurricane. A majority of the guidance this morning shows Simon remaining just offshore, however most of these models have historically had a west bias in this region. Likewise, ensemble means like GDM or even HCCA can be misleading when some members move inland and dissipate. This results in the mean being computed solely from the surviving, and in this case farther west, members. The NHC forecast therefore remains within, but on the east side of the guidance envelope, and is best characterized as a hedge between the aforementioned possibilities. Key Messages: 1. Simon is expected to approach the west-central coast of Mexico as a major hurricane on Saturday. 2. Catastrophic wind and life-threatening storm surge impacts are likely along a portion of the west-central coast of Mexico, and a Hurricane warning is in effect from Punta San Telmo to Punta Mita. Preparations to protect life and property should be completed by late today. 3. Heavy rainfall associated with Simon will impact portions of southwestern Mexico through this weekend. This rainfall may produce life-threatening flooding and mudslides, especially in areas of steep terrain. 4. Swells will affect portions of the southwestern and west-central coast of Mexico through the weekend. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office. FORECAST POSITIONS AND MAX WINDS INIT 09/1500Z 16.0N 104.7W 85 KT 100 MPH 12H 10/0000Z 16.5N 104.8W 105 KT 120 MPH 24H 10/1200Z 17.2N 104.9W 125 KT 145 MPH 36H 11/0000Z 18.2N 105.0W 125 KT 145 MPH 48H 11/1200Z 19.4N 105.2W 115 KT 130 MPH 60H 12/0000Z 20.7N 105.4W 95 KT 110 MPH...INLAND 72H 12/1200Z 21.9N 105.6W 75 KT 85 MPH...OVER WATER 96H 13/1200Z 23.6N 106.2W 55 KT 65 MPH...INLAND 120H 14/1200Z 24.9N 106.9W 30 KT 35 MPH...POST-TROP/INLAND $$ Forecaster D. Zelinsky  183 WTPZ45 KNHC 092046 TCDEP5 Hurricane Simon Discussion Number 10 NWS National Hurricane Center Miami FL EP202026 300 PM CST Fri Oct 09 2026 An intermittent warm spot in the CDO of Simon has been present since this morning, co-located with a small pinhole-like eye noted in visible imagery. The initial intensity of 90 kt is based primarily on the latest TAFB Dvorak fix, though this is very uncertain due to the very small size of Simon and intensity estimates range from around 65 kt (DMINT) to 97 KT (RCM-1 SAR). The SAR data this morning indicated the system has an RMW near 5 n mi, highlighting how small it is. Simon has continued to strengthen today, although at a slightly slower rate since this morning. Further rapid intensification is still anticipated but the exact timing of when the rate might pick up again is highly uncertain. Small hurricanes like Simon are particularly susceptible to large and rapid fluctuations in intensity. In the short term, no changes of note were made to the NHC intensity forecast, which remains at the high end of the guidance envelope. The main challenge with this forecast is how sensitive it is to the exact track Simon takes over the next 2 days and whether or not it moves inland over the Mexican states of Colima and Jalisco. A track slightly east of the NHC official forecast track will cause Simon to quickly dissipate and minimize the threat of wind impacts farther north in Mexico. However, a track just to the west would likely allow Simon to move much farther north as a hurricane. At this time, the difference between these track scenarios is less than the average error of NHC forecasts. Most of the deterministic global models shifted slightly east this cycle, but ensemble guidance indicates both scenarios are still plausible. The NHC track and intensity forecast therefore is largely unchanged and continues to show Simon tracking farther north than it might realistically make it to emphasize that risk. Key Messages: 1. Catastrophic wind and life-threatening storm surge impacts are likely along a portion of the west-central coast of Mexico, and a Hurricane warning is in effect from Punta San Telmo to Punta Mita. Preparations to protect life and property should be completed by late today. 2. Heavy rainfall associated with Simon will impact portions of southwestern Mexico through this weekend. This rainfall will produce life-threatening flooding and mudslides, especially in areas of steep terrain. 3. Swells will affect portions of the southwestern and west-central coast of Mexico through the weekend. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office. FORECAST POSITIONS AND MAX WINDS INIT 09/2100Z 16.2N 104.7W 90 KT 105 MPH 12H 10/0600Z 16.6N 104.9W 110 KT 125 MPH 24H 10/1800Z 17.5N 105.0W 125 KT 145 MPH 36H 11/0600Z 18.6N 105.1W 115 KT 130 MPH 48H 11/1800Z 20.0N 105.3W 95 KT 110 MPH...INLAND 60H 12/0600Z 21.4N 105.5W 75 KT 85 MPH...OVER WATER 72H 12/1800Z 22.8N 105.8W 60 KT 70 MPH...INLAND 96H 13/1800Z 24.6N 106.4W 30 KT 35 MPH...POST-TROP/INLAND 120H 14/1800Z...DISSIPATED $$ Forecaster D. Zelinsky  485 WTPZ45 KNHC 100836 TCDEP5 Hurricane Simon Discussion Number 12 NWS National Hurricane Center Miami FL EP202026 300 AM CST Sat Oct 10 2026 The very small inner-core of Simon remains very impressive as the cyclone has continued to strengthen. The proxy-visible imagery has started to show that the tiny eye of the hurricane is clearing out. The most recent TAFB Dvorak fix was a T6.0/115 kt, while the objective raw T-number intensity estimates from UW-CIMSS have ranged from 120 to 132 kt. Based on a blend of the objective and subjective intensity estimates, the initial intensity has been increased to 120 kt for this advisory. The wind radii has been adjusted based on a recent ASCAT pass. The hurricane is expected to continue to rapidly strengthen over the next day or so, with a peak intensity of 135 kt forecast. Given the small size of the inner core, there is a higher than normal degree of uncertainty with the peak intensity. Therefore, it is possible that Simon could become stronger than what is forecast. Only a few changes were made for the current NHC forecast compared to the previous forecast. Simon's initial motion is estimated at 360/4 kt, northward. The hurricane is being steered by the southerly mid-level flow produced by high pressure over southern Mexico and a longwave mid-tropospheric trough to the west stretching south-southwestward from the southwest United States. There is still some uncertainty about the track for Simon, as most of the skilled model guidance including HCCA and GDMI forecast aids have been experiencing to the left of the track bias. The current NHC track forecast has the hurricane move inland over the Mexican states of Colima and Jalisco; however, it is possible that the cyclone could remain just offshore as it moves generally northward. Should Simon move inland, then it should dissipate quickly due to the mountainous terrain. However, if Simon were to stay offshore, then it would maintain hurricane intensity for a longer period of time. The current track forecast is similar to the previous one, with only a few small adjustments being made. Key Messages: 1. Catastrophic wind and life-threatening storm surge impacts are likely along a portion of the west-central coast of Mexico, and a Hurricane warning is in effect from Punta San Telmo to Punta Mita. Preparations to protect life and property should be completed today. 2. Heavy rainfall associated with Simon will impact portions of southwestern Mexico through this weekend. This rainfall will produce life-threatening flooding and mudslides, especially in areas of steep terrain. 3. Swells will affect portions of the southwestern and west-central coast of Mexico through the weekend. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office. FORECAST POSITIONS AND MAX WINDS INIT 10/0900Z 17.2N 104.6W 125 KT 145 MPH 12H 10/1800Z 17.8N 104.7W 135 KT 155 MPH 24H 11/0600Z 18.8N 104.9W 135 KT 155 MPH 36H 11/1800Z 20.0N 105.1W 120 KT 140 MPH...INLAND 48H 12/0600Z 21.7N 105.3W 70 KT 80 MPH...INLAND 60H 12/1800Z 23.1N 105.6W 30 KT 35 MPH...POST-TROP/INLAND 72H 13/0600Z...DISSIPATED $$ Forecaster Katz/Roberts  438 WTPZ45 KNHC 100857 TCDEP5 Hurricane Simon Discussion Number 12 NWS National Hurricane Center Miami FL EP202026 300 AM CST Sat Oct 10 2026 The very small inner-core of Simon remains very impressive as the cyclone has continued to strengthen. The proxy-visible imagery has started to show that the tiny eye of the hurricane is clearing out. The most recent TAFB Dvorak fix was a T6.0/115 kt, while the objective raw T-number intensity estimates from UW-CIMSS have ranged from 120 to 132 kt. Based on a blend of the objective and subjective intensity estimates, the initial intensity has been increased to 125 kt for this advisory. The wind radii has been adjusted based on a recent ASCAT pass. The hurricane is expected to continue to rapidly strengthen over the next day or so, with a peak intensity of 135 kt forecast. Given the small size of the inner core, there is a higher than normal degree of uncertainty with the peak intensity. Therefore, it is possible that Simon could become stronger than what is forecast. Only a few changes were made for the current NHC forecast compared to the previous forecast. Simon's initial motion is estimated at 360/4 kt, northward. The hurricane is being steered by the southerly mid-level flow produced by high pressure over southern Mexico and a longwave mid-tropospheric trough to the west stretching south-southwestward from the southwest United States. There is still some uncertainty about the track for Simon, as most of the skilled model guidance including HCCA and GDMI forecast aids have been experiencing to the left of the track bias. The current NHC track forecast has the hurricane move inland over the Mexican states of Colima and Jalisco; however, it is possible that the cyclone could remain just offshore as it moves generally northward. Should Simon move inland, then it should dissipate quickly due to the mountainous terrain. However, if Simon were to stay offshore, then it would maintain hurricane intensity for a longer period of time. The current track forecast is similar to the previous one, with only a few small adjustments being made. Key Messages: 1. Catastrophic wind and life-threatening storm surge impacts are likely along a portion of the west-central coast of Mexico, and a Hurricane warning is in effect from Punta San Telmo to Punta Mita. Preparations to protect life and property should be completed today. 2. Heavy rainfall associated with Simon will impact portions of southwestern Mexico through this weekend. This rainfall will produce life-threatening flooding and mudslides, especially in areas of steep terrain. 3. Swells will affect portions of the southwestern and west-central coast of Mexico through the weekend. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office. FORECAST POSITIONS AND MAX WINDS INIT 10/0900Z 17.2N 104.6W 125 KT 145 MPH 12H 10/1800Z 17.8N 104.7W 135 KT 155 MPH 24H 11/0600Z 18.8N 104.9W 135 KT 155 MPH 36H 11/1800Z 20.0N 105.1W 120 KT 140 MPH...INLAND 48H 12/0600Z 21.7N 105.3W 70 KT 80 MPH...INLAND 60H 12/1800Z 23.1N 105.6W 30 KT 35 MPH...POST-TROP/INLAND 72H 13/0600Z...DISSIPATED $$ Forecaster Katz/Roberts  181 WTPZ45 KNHC 110233 TCDEP5 Hurricane Simon Discussion Number 15 NWS National Hurricane Center Miami FL EP202026 900 PM CST Sat Oct 10 2026 The compact core of very dangerous Hurricane Simon is inching toward west-central Mexico. The northern eyewall is only about 30 n mi off the coast, and conditions are expected to quickly deteriorate later tonight. The major hurricane appears to be getting stronger and has a distinct and small eye, surrounded by symmetric and intense deep convection. The initial intensity is nudged up to 135 kt, near the upper end of the latest satellite estimates. The Air Force Hurricane Hunters are scheduled to investigate the system in a few hours, and the data they collect will be very helpful to better assess Simon's intensity and structure. Simon has been crawling northward, with the latest initial motion estimated to be 360/4 kt. A slightly faster northward or north-northwestward motion is expected later tonight, and the major hurricane will either make landfall or skirt the coast of west-central Mexico on Sunday. The models remain inconsistent in showing whether landfall will occur or not. Regardless, significant or catastrophic wind, surge, and rainfall appears likely over portions of west-central Mexico later tonight and Sunday. Fluctuations in strength are expected until the core of Simon reaches the coast. Rapid weakening is forecast once the system interacts with land, and it could weaken at a much faster pace if it moves to the east of the official track. Due to the complexity of how much land Simon will interacts with, the intensity forecast is of low confidence. Key Messages: 1. Catastrophic wind and life-threatening storm surge impacts are likely along a portion of the west-central coast of Mexico, and a Hurricane Warning is in effect from Punta San Telmo to El Roblito. Preparations to protect life and property should be rushed to completion. 2. Heavy rainfall associated with Simon will impact portions of southwestern Mexico through this weekend. This rainfall will produce life-threatening flooding and mudslides, especially in areas of steep terrain. 3. Swells will affect portions of the southwestern and west-central coast of Mexico over the next few days. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office. FORECAST POSITIONS AND MAX WINDS INIT 11/0300Z 18.2N 104.8W 135 KT 155 MPH 12H 11/1200Z 19.1N 105.0W 135 KT 155 MPH...NEAR THE COAST 24H 12/0000Z 20.1N 105.3W 100 KT 115 MPH...NEAR THE COAST 36H 12/1200Z 21.1N 105.5W 60 KT 70 MPH...NEAR THE COAST 48H 13/0000Z 22.0N 105.6W 35 KT 40 MPH...NEAR THE COAST 60H 13/1200Z 23.0N 105.9W 15 KT 15 MPH...POST-TROP/INLAND 72H 14/0000Z...DISSIPATED $$ Forecaster Cangialosi  866 WTPZ45 KNHC 112112 CCA TCDEP5 Hurricane Simon Discussion Number 18...Corrected NWS National Hurricane Center Miami FL EP202026 300 PM CST Sun Oct 11 2026 Corrected spelling of Sierra in first sentence. Simon is still a Category 4 hurricane, but appears to be feeling the effects of the nearby high terrain of the Sierra Madre Mountains as the inner core is brushing up against the Mexican coast. The eye remains observed on geostationary satellite imagery, but is more cloud filled than earlier with warmer surrounding cloud tops. While the 18 UTC subjective Dvorak fix was still at T6.5/125 kt, the objective intensity estimates have continued to fall, with values now in the 109-115 kt range. Therefore, the initial intensity is being lowered to 115 kt for this advisory. An earlier Synthetic Aperture Radar (SAR) RCM-1 pass was very useful to adjust the 34- 50- and 64-kt radii of Simon as the hurricanes wind field continues to shrink in size. Simon has stubbornly maintained a north-northwestward motion, roughly parallel to the coastline, estimated at 335/5 kt. It is now looking increasingly likely that Simon will avoid making a direct landfall in the short-term, though its eastern inner core will likely produce hurricane conditions as the storm continues to move north-northwestward from Playa Perula to Cabo Corrientes this afternoon and evening. The steering ridge centered over the Texas coast is likely to maintain this motion now for the next several days, though with some slowdown in the motion due to a weaker but competing ridge located to Simon's southwest. On Tuesday into Wednesday, a large short-wave trough is forecast to move across the southwestern United States and this feature should provide enough southwesterly environmental flow to turn the hurricane to the northeast, finally reaching the coast of Mexico in 60-72 h. Compared to this morning, the guidance has shifted westward and slower once again, and there remain some outlier solutions like the GFS that want to turn Simon southwestward beyond 48 h. However, the majority of the ensemble guidance (European-EPS, Google DeepMind) do show this slow recurving solution back into Mexico. The NHC track forecast is a little bit west and slower for the first 36-48 h, but then bends back to the previous forecast track thereafter, still showing Simon moving inland and dissipating in the day 3-4 period. This forecast still remains low confidence. Intensity wise, it is now looking more likely that Simon will not weaken as much as originally expected, now that it is only brushing up against the coast instead of part of its inner core moving inland. Still, the high topography in Jalisco should still have a negative effect, which has already been seen in Simon's wind field shrinking in size. The hurricane-regional models still show significant weakening over the next 12-24 h, even the ones that only skirt the coast of Mexico, and the NHC intensity forecast still shows a fast rate of weakening during that time. However, other environmental conditions remain very favorable, as shear stays under 10 kt, and sea-surface temperatures warm to 31-32 C as Simon passes north of Cabo Corrientes and enters waters that have been unaffected by recent tropical cyclones (Polo and Rachel). However, there will be a significant amount of nearby dry air and it remains to be seen how intact Simon's inner core will remain over the next 24 h of near land interaction. The latest NHC intensity forecast now shows Simon maintaining hurricane intensity, and this forecast could still be low if the inner core remains more robust than the hurricane regional models are forecasting. This forecast is now on the higher end of the intensity guidance aids, but is under the SHIPS guidance this cycle, and also remains low confidence. Key Messages: 1. Catastrophic wind and life-threatening storm surge impacts are likely along a portion of the west-central coast of Mexico, and a Hurricane Warning is in effect from Punta San Telmo to El Roblito. Residents should continue to shelter in a safe room to ride out the storm as the most significant hazards with Simon are now ongoing. 2. Simon is now expected to approach the coast of west Mexico later this week, where Hurricane conditions are now possible along the coast of El Roblito to Bahia Tempehuaya. A Hurricane Watch is now in effect for this region. 3. Heavy rainfall associated with Simon will impact portions of southwestern and west-central Mexico over the next few days. This rainfall will produce life-threatening flooding and mudslides, especially in areas of steep terrain. 4. Swells will affect portions of the southwestern and west-central coast of Mexico over the next few days. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office. FORECAST POSITIONS AND MAX WINDS INIT 11/2100Z 19.6N 105.8W 115 KT 130 MPH 12H 12/0600Z 20.2N 106.1W 90 KT 105 MPH 24H 12/1800Z 21.0N 106.6W 80 KT 90 MPH 36H 13/0600Z 21.6N 106.9W 75 KT 85 MPH 48H 13/1800Z 22.2N 107.1W 75 KT 85 MPH 60H 14/0600Z 22.8N 107.0W 75 KT 85 MPH 72H 14/1800Z 23.4N 106.6W 75 KT 85 MPH 96H 15/1800Z 24.0N 105.9W 30 KT 35 MPH...POST-TROP/INLAND 120H 16/1800Z...DISSIPATED $$ Forecaster Papin  419 WTPZ45 KNHC 120251 TCDEP5 Hurricane Simon Discussion Number 19 NWS National Hurricane Center Miami FL EP202026 800 PM MST Sun Oct 11 2026 Simon is showing signs of weakening this evening, likely due to its prolonged close proximity to the Mexican coastline and the associated negative affects of nearby mountainous terrain. Infrared satellite imagery indicates warming cloud tops within the convection in the northeastern quadrant, with mid-level dry air beginning to wrap around the western side of the cyclone. Recent objective Dvorak intensity estimates have decreased over the past several hours and range from 99-110 kt. Based on the deteriorating satellite presentation and the lower intensity estimates, the initial intensity is set at 105 kt for this advisory. The major hurricane is moving slowly north-northwestward, steered by a mid-level ridge centered over the south-central United States. Simon is forecast to track parallel to the coast of west-central Mexico over the next day or so. However, its continued close proximity to land will likely bring hurricane conditions to portions of the warning area, particularly near Cabo Corrientes, even though the core is forecast to remain just offshore. Around midweek, a strong upper-level low moving across the western United States is expected to induce a turn toward the north and then northeast. Although there remains some model spread, an increasing number of the hurricane regional models and consensus aids, including HCCA, bring Simon onshore around midweek. The latest NHC forecast is very similar to the previous advisory, showing Simon moving inland and dissipating in the day 3-4 period. Gradual weakening is expected due to the proximity to the mountainous terrain, which could further disrupt the hurricane's structure along its eastern side. A slight increase in wind shear and the entrainment of drier mid-level air should further contribute to the weakening trend. However, as Simon turns northward then northeastward around midweek, it is forecast to move over very warm waters of 31-32 C, which could limit further weakening before landfall. The latest NHC forecast has been nudged upward slightly beyond 12 h, with Simon expected to maintain hurricane strength through landfall. This forecast lies near the middle of the intensity guidance envelope. Rapid weakening is expected once Simon moves inland, and dissipation is forecast by 96 h. Key Messages: 1. Catastrophic wind and life-threatening storm surge impacts are likely along a portion of the west-central coast of Mexico, and a Hurricane Warning is in effect from Playa Perula to El Roblito. Residents should continue to shelter in a safe room to ride out the storm as the most significant hazards are ongoing. 2. Simon is expected to approach the coast of western Mexico later this week, where hurricane conditions are possible. A Hurricane Watch is in effect from El Roblito to Bahia Tempehuaya. 3. Heavy rainfall associated with Simon will impact portions of southwestern and west-central Mexico over the next few days. This rainfall will produce life-threatening flooding and mudslides, especially in areas of steep terrain. 4. Swells will affect portions of the southwestern and west-central coast of Mexico over the next few days. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office. FORECAST POSITIONS AND MAX WINDS INIT 12/0300Z 19.8N 106.0W 105 KT 120 MPH 12H 12/1200Z 20.5N 106.3W 95 KT 110 MPH 24H 13/0000Z 21.2N 106.8W 85 KT 100 MPH 36H 13/1200Z 21.8N 107.1W 80 KT 90 MPH 48H 14/0000Z 22.4N 107.0W 80 KT 90 MPH 60H 14/1200Z 23.0N 106.7W 80 KT 90 MPH 72H 15/0000Z 23.4N 106.4W 65 KT 75 MPH...INLAND 96H16/0000Z 24.0N 105.7W 30 KT 35 MPH...POST-TROP/INLAND 120H 17/0000Z...DISSIPATED $$ Forecaster Adams/Cangialosi  784 WTPZ45 KNHC 120854 TCDEP5 Hurricane Simon Discussion Number 20 NWS National Hurricane Center Miami FL EP202026 200 AM MST Mon Oct 12 2026 Simon continues to show signs of weakening as the eye has become filled in, although infrared imagery shows that the central dense overcast has cooled since the previous advisory. There is a wide spread in intensity estimates, ranging from 73-127 kt. Since there has been an overall modest degradation to the cloud pattern, the current intensity is nudged downward to 100 kt. The initial wind radii were modified with the help of timely SAR pass. The cyclone is drifting off to the northwest as it is being steered by a distant mid-level ridge centered over the south-central United States. Simon is expected to continue moving slowly near the coast of Mexico for the next few days. However, there is still a higher than normal amount of uncertainty in the track, and some models show that Simon gets trapped in an area of light steering between the US ridge and one well southwest of Simon. Later, a trough from the northwest will approach the hurricane and force Simon to turn toward the northeast with increasing forward speed, though the timing of this turn is uncertain. The latest NHC forecast is just west of the previous advisory after considering some of the latest AI-based guidance. Weakening is expected to continue due to Simon's proximity to the mountainous terrain, as well as some easterly wind shear. However, the sea-surface temperatures that Simon will be moving across later this week are around 31-32 C, which could moderate the weakening trend, as well as the new track being slightly farther offshore. The current NHC intensity forecast is generally the same as the previous forecast with only a few adjustments. Simon is still expected to rapidly weakening once the cyclone makes landfall around 72 h. Key Messages: 1. Dangerous wind and storm surge impacts are likely along a portion of the west-central coast of Mexico, and a Hurricane Warning is in effect from Playa Perula to El Roblito. Residents should continue to shelter in a safe room to ride out the storm as the most significant hazards are ongoing. 2. Simon is expected to approach the coast of western Mexico later this week, where hurricane conditions are possible. A Hurricane Watch is in effect from El Roblito to Bahia Tempehuaya. 3. Heavy rainfall associated with Simon will impact portions of southwestern and west-central Mexico over the next few days. This rainfall will produce life-threatening flooding and mudslides, especially in areas of steep terrain. 4. Large swells will affect portions of the southwestern and west-central coasts of Mexico over the next few days. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office. FORECAST POSITIONS AND MAX WINDS INIT 12/0900Z 20.0N 106.3W 100 KT 115 MPH 12H 12/1800Z 20.6N 106.7W 90 KT 105 MPH 24H 13/0600Z 21.2N 107.1W 85 KT 100 MPH 36H 13/1800Z 21.8N 107.3W 80 KT 90 MPH 48H 14/0600Z 22.3N 107.2W 80 KT 90 MPH 60H 14/1800Z 22.9N 107.0W 80 KT 90 MPH 72H 15/0600Z 23.4N 106.6W 70 KT 80 MPH...INLAND 96H 16/0600Z 24.1N 105.8W 20 KT 25 MPH...POST-TROP/INLAND 120H 17/0600Z...DISSIPATED $$ Forecaster Katz/Blake  288 WTPZ45 KNHC 122053 TCDEP5 Hurricane Simon Discussion Number 22 NWS National Hurricane Center Miami FL EP202026 200 PM MST Mon Oct 12 2026 This afternoon, Simon is a small hurricane that is dealing with some easterly vertical wind shear. The inner-core continues to produce a lot of lightning but mostly in the eastern semicircle. The most recent microwave image was a 1718 UTC AWS pass that also showed this core asymmetry with the eyewall open on the northwest side on the 180 GHz channel. While the latest 18 UTC subjective Dvorak estimate remains at CI 5.5/102-kt, the objective intensity estimates from UW-CIMSS continue to gradually decrease. Thus, the initial intensity is being reduced to a somewhat uncertain 85 kt this advisory, which also matches the D-MINT mean estimate from the AWS microwave pass above. A helpful 1712 UTC Metop-C scatterometer pass was useful to help adjust Simon's radii and also to indicate its wind field has become quite small, with 34-kt winds only extending out about 40 n mi. Simon's track has thrown us a few curve balls over the past 24-36 h, and this afternoon is no exception as the hurricane made a brief westward jog, with the longer-term motion estimated at 290/3 kt. The track forecast remains problematic. Part of the slow motion Simon is exhibiting today is related to competing steering synoptic features, primarily a mid-level ridge centered near the Texas Coast versus another mid-level ridge located southwest of the hurricane. The influence of the northeastern ridge has been a little stronger, but steering diagnostics suggest that Simon may be soon reaching a bifurcation or COL point in the flow. This feature indicates the area where the net steering flow collapses and helps explain why both the deterministic and ensemble track guidance spread increases quite dramatically in 24 to 48 h. For example, the HAFS-A/B models, which earlier this morning were showing a faster northeastward turn back into Mexico, now show Simon stalling and executing a slow cyclonic loop in the waters between mainland Mexico and the southern tip of the Baja California Peninsula. The European ensemble spread suggests that these individual solutions are likely just different flavors of the overall distribution, which is spread out in a southwest to northeast fashion. While the overall track guidance continues to have large spread, there has been a northward and faster shift this cycle. This shift is a bit odd given the current storm motion, so the NHC track forecast is initially on the left side of the guidance over the first 12-24 h, but falls back closer to the middle of the guidance envelope, and attempts to blend the latest HFIP Corrected Consensus Approach (HCCA), Google Deepmind ensemble mean (GDMI), and their latest Weather Next model (WN3I). Ultimately the latest track forecast converges close to the prior one near landfall in Mexico in 72-96 h, but this remains a low confidence track forecast. The intensity forecast for Simon is also challenging. The current mid-level easterly shear affecting Simon's inner core structure has not been well anticipated by the model guidance. Small tropical cyclones like Simon are often more sensitive to negative environmental factors, and even 15-20 kt of easterly shear could be enough to disrupt the core structure, especially with nearby environmental dry air. The factors may result in additional weakening in the short-term. However, EC-SHIPS guidance shows the shear lowering below 5 kt in 24-48 h. Assuming Simon is able to maintain an inner core structure and take advantage of the more favorable conditions, restrengthening is still forecast, especially as the hurricane is expected to track over the warmest sea-surface temperatures in the Eastern Pacific basin (31-32 C). The intensity guidance shows more short-term weakening compared to the previous cycle, and the NHC intensity forecast is lower early on, but still shows restrengthening as Simon encounters those more favorable conditions, and ends up on the high end of the intensity guidance in 60-72 h. Small storms like Simon can also be prone to rapid changes in intensity, which continues to make this intensity forecast also more uncertain than usual. Rapid weakening is still anticipated when Simon eventually makes landfall in the latter part of this week between 72-96 h. Key Messages: 1. Hurricane conditions are likely on Las Islas Marias over the next day or so, where a Hurricane Warning remains in effect. 2. Simon is expected to approach the coast of western Mexico later this week, where hurricane conditions are possible. A Hurricane Watch is in effect from Cabo Corrientes to Bahia Tempehuaya. 3. Heavy rainfall associated with Simon will impact portions of west-central Mexico over the next few days. This rainfall will produce life-threatening flooding and mudslides, especially in areas of steep terrain. 4. Large swells will affect portions of the southwestern and west-central coasts of Mexico over the next few days. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office. FORECAST POSITIONS AND MAX WINDS INIT 12/2100Z 20.2N 106.8W 85 KT 100 MPH 12H 13/0600Z 20.5N 107.0W 75 KT 85 MPH 24H 13/1800Z 20.9N 107.5W 65 KT 75 MPH 36H 14/0600Z 21.2N 107.7W 70 KT 80 MPH 48H 14/1800Z 21.5N 107.7W 75 KT 85 MPH 60H 15/0600Z 22.2N 107.4W 80 KT 90 MPH 72H 15/1800Z 23.0N 107.0W 85 KT 100 MPH 96H 16/1800Z 24.2N 106.6W 30 KT 35 MPH...POST-TROP/INLAND 120H 17/1800Z...DISSIPATED $$ Forecaster Papin  446 WTPZ45 KNHC 130255 TCDEP5 Hurricane Simon Discussion Number 23 NWS National Hurricane Center Miami FL EP202026 800 PM MST Mon Oct 12 2026 Simon's convection has degraded quite a bit since the last advisory. Given how much of this weakening has been concentrated across the eastern half of the storm, it is possible that Simon has been ingesting dry, high terrain air into its center. Regardless of the physical mechanism, however, both subjective and objective Dvorak intensity estimates have picked up on this weakening trend, as the TAFB Dvorak classification rates Simon at 5.0/90 kt and UW-CIMSS estimates range from 51 to 72 kt. As a result of these data, Simon's initial intensity has been lowered to 85 kt. The storm motion remains very slow at 305/3 kt. Simon is riding the western flank of a high pressure ridge centered over the southeastern US, with high pressure building to the storm's west as well in the wake of a deep trough currently enveloping the Intermountain West. Simon is battling a multitude of features influencing its motion as a result, and track guidance continues to exhibit a wide spread of solutions. Thus, confidence in the track forecast remains low. The global models, however, do seem to agree that the high anchored over the southeastern US will remain for at least the next 48 hours, so the current forecast thinking is that Simon will not make a turn toward land in the meantime. What becomes of that high once the aforementioned trough moves eastward across the US is what will ultimately determine Simon's path. Looking at the global models, the GFS depicts the trough doing little to erode the southeastern high, leaving Simon to become caught in a col as it is wedged between two high pressure systems, thus causing it to become nearly stationary over the next couple of days. The ECMWF, however, seems to suggest that the trough will dig deep enough to cause a turn to the northeast toward land over the next 48 hours. More skilled guidance like the HCCA and GDMI, however, seem to favor a due northwest track, likely stemming from the southeastern US high remaining fixed in place and the high to the west not building enough to affect Simon's motion. The latest NHC track forecast favors this solution, while still depicting a turn to the northeast after a couple of days should this Pacific high strengthen enough to nudge Simon off its current trajectory. Should Simon continue to move northwestward, as is currently forecast, gradual re-strengthening should follow. The environment just off the coast of west-central Mexico continues to be defined by low vertical wind shear, anomalously warm SSTs, and ample mid-level moisture. Should the storm become nearly stationary as some models suggest, however, re-intensification could be inhibited by Simon churning up cooler waters from deep below the sea surface. It should be noted that the current consensus across the guidance does not favor a period of rapid intensification, so the latest NHC intensity forecast continues to reflect a more gradual upward trend in strength, before dropping off sharply once Simon makes its forecasted approach to land. With confidence lacking in the track forecast, however, Simon's intensity forecast confidence is only low to moderate. Key Messages: 1. Hurricane conditions are likely on Las Islas Marias over the next day or so, where a Hurricane Warning remains in effect. 2. Simon could approach the coast of western Mexico later this week, where hurricane conditions are possible. 3. Heavy rainfall associated with Simon will impact portions of west-central Mexico over the next few days. This rainfall will produce life-threatening flooding and mudslides, especially in areas of steep terrain. 4. Large swells will affect portions of the southwestern and west-central coasts of Mexico over the next several days. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office. FORECAST POSITIONS AND MAX WINDS INIT 13/0300Z 20.4N 107.0W 85 KT 100 MPH 12H 13/1200Z 20.7N 107.3W 75 KT 85 MPH 24H 14/0000Z 21.0N 107.7W 70 KT 80 MPH 36H 14/1200Z 21.3N 108.0W 70 KT 80 MPH 48H 15/0000Z 21.8N 108.0W 75 KT 85 MPH 60H 15/1200Z 22.5N 107.9W 80 KT 90 MPH 72H 16/0000Z 23.2N 107.8W 85 KT 100 MPH 96H 17/0000Z 24.0N 107.6W 85 KT 100 MPH 120H 18/0000Z 24.8N 107.3W 30 KT 35 MPH...POST-TROP/INLAND $$ Forecaster Evans/Cangialosi  960 WTPZ45 KNHC 140236 TCDEP5 Hurricane Simon Discussion Number 27 NWS National Hurricane Center Miami FL EP202026 800 PM MST Tue Oct 13 2026 After holding steady for the past 18-24 hours, Simon is re-intensifying. The eye of the hurricane has become distinct, and deep convection is more intense and symmetric around the eye. The initial intensity has been increased to 95 kt near a Dvorak classification from TAFB. Although Simon's peak winds appear to have increased significantly, the hurricane remains tiny. The hurricane- and tropical-storm-force winds are estimated to only extend up to 10 and 30 n mi from the center, respectively. The compact hurricane is drifting westward off the coast of west-central Mexico. The steering currents are expected to remain very weak for the next couple of days, and most of the models show Simon drifting southwestward during that time. By the end of the week and over the weekend, the model solutions diverge significantly, and the differences appear to be due to the location and depth of Simon and a mid- to upper-level trough over the western U.S. The new forecast shows a slower motion from days 3 to 5, in better agreement with the latest models. Some additional strengthening is possible tonight, and Simon could become a major hurricane again. However, slow weakening seems likely after that time due to an increase in vertical wind shear, intrusions of dry air, and possibly ocean upwelling. The NHC intensity forecast is raised from the previous one in the short term, but is similar to the prior forecast beyond a couple of days. Simon has been a very challenging storm to forecast, and confidence for this cycle remains low given the weak steering, proximity to land, very small size, and significant model spread. Key Messages: 1. Simon could be near Las Islas Marias on Thursday, where a Hurricane Watch remains in effect. Interests in west-central Mexico and Baja California Sur should continue to closely monitor the latest updates. Additional watches or warnings could be required over the next day or two. 2. Large swells will likely affect portions of the coast of west-central Mexico and Baja California Sur over the next several days. These swells could cause life-threatening surf and rip current conditions. FORECAST POSITIONS AND MAX WINDS INIT 14/0300Z 20.1N 107.6W 95 KT 110 MPH 12H 14/1200Z 20.1N 107.8W 105 KT 120 MPH 24H 15/0000Z 19.6N 108.2W 95 KT 110 MPH 36H 15/1200Z 18.9N 108.5W 85 KT 100 MPH 48H 16/0000Z 19.7N 108.1W 75 KT 85 MPH 60H 16/1200Z 21.0N 108.0W 65 KT 75 MPH 72H 17/0000Z 22.3N 108.8W 55 KT 65 MPH 96H 18/0000Z 24.1N 109.7W 40 KT 45 MPH 120H 19/0000Z 27.2N 110.9W 30 KT 35 MPH...POST-TROP/REMNT LOW $$ Forecaster Cangialosi  647 WTPZ45 KNHC 140846 TCDEP5 Hurricane Simon Discussion Number 28 NWS National Hurricane Center Miami FL EP202026 200 AM MST Wed Oct 14 2026 Proxy-visible and infrared satellite images of Simon show the tiny eye of the hurricane has filled during the past few hours. There has also been a warming of the inner core cloud tops, and the central dense overcast has become less symmetric. These changes could be the result of some northerly shear affecting Simon as diagnosed by UW-CIMSS. There is no recent passive microwave data available to assess the internal structure of Simon, but recent scatterometer data and distant radar data from Los Cabos indicate that the hurricane remains very small. The initial intensity is lowered slightly to 90 kt, in best agreement with the latest Dvorak CI number (5.0) from TAFB and an earlier 88-kt D-MINT estimate. The hurricane is moving slowly southwestward (230/3 kt). In the near term, Simon is expected to remain within very weak steering currents. Thus, it is likely to meander well offshore of west-central Mexico during the next couple of days, with the model consensus generally favoring a slow southwestward or southward motion through Thursday. From there, the future track will depend on the vertical depth of Simon and its interaction with an upper-level trough over the western United States. This feature should cause Simon to turn northward at some point, but there is large spread among the track models as to when and where this turn occurs. There has been a substantial westward shift in the long-range track guidance, with almost all models now bringing Simon near or west of the Baja California Peninsula at 72-120 h. The NHC forecast has been adjusted in the direction of the latest multi-model consensus to reflect this trend, but future adjustments will likely be required. Simon's small size makes it susceptible to intensity fluctuations based on the state of its compact inner core and small changes in the environmental conditions. The hurricane is forecast to drift over very warm waters in a fairly weak shear environment during the next day or two. However, the mid-level environmental humidity is only around 50 percent, and even slightly stronger shear than forecast could disrupt the core and induce some weakening. The official NHC forecast shows little net change in the next 24-36 h, recognizing that some of the hurricane regional models show another round of strengthening could occur during this period. There is higher confidence that the aforementioned trough will impart stronger vertical wind shear over Simon by Friday, which should induce a steady weakening trend through the weekend. Simon continues to be a challenging storm to forecast, and confidence remains lower than normal given the weak steering, proximity to land, very small size, and significant model spread. Key Messages: 1. Simon could be near Las Islas Marias on Thursday, where a Hurricane Watch remains in effect. Interests in west-central Mexico and Baja California Sur should continue to closely monitor the latest updates. Additional watches or warnings could be required over the next day or two. 2. Large swells will likely affect portions of the coast of west-central Mexico and Baja California Sur over the next several days. These swells could cause life-threatening surf and rip current conditions. FORECAST POSITIONS AND MAX WINDS INIT 14/0900Z 19.8N 107.9W 90 KT 105 MPH 12H 14/1800Z 19.6N 108.0W 95 KT 110 MPH 24H 15/0600Z 19.4N 108.1W 90 KT 105 MPH 36H 15/1800Z 19.2N 108.3W 90 KT 105 MPH 48H 16/0600Z 19.6N 108.5W 80 KT 90 MPH 60H 16/1800Z 20.9N 109.1W 65 KT 75 MPH 72H 17/0600Z 22.4N 109.8W 50 KT 60 MPH 96H 18/0600Z 24.6N 111.1W 35 KT 40 MPH...POST-TROP/INLAND 120H 19/0600Z 27.1N 113.0W25 KT 30 MPH...POST-TROP/INLAND $$ Forecaster Reinhart  272 WTPZ45 KNHC 141449 TCDEP5 Hurricane Simon Discussion Number 29 NWS National Hurricane Center Miami FL EP202026 800 AM MST Wed Oct 14 2026 First-light visible imagery indicates that Simon has continued to lose organization during the last several hours. The low-level center is now located near the northern edge of the convective overcast due to the effects of northerly shear. However, there is still no microwave imagery of the storm to better diagnose the internal structure. The satellite intensity estimates have trended down, and based on this the initial intensity is reduced to a possibly generous 80 kt. The hurricane continues drifting southwest or 230/2 kt. For the next day or two, Simon is likely to continue drifting southwestward in an area of light steering currents, with the center remaining well offshore. After that time, the track forecast becomes less confident. While all of the global models agree that a mid- to upper-level trough should form west of Baja California after 48 h, there is poor agreement on the track forecasts for Simon during this time. The GFS and the regional hurricane models forecast that Simon will continue moving southward or southwestward through 72 h, followed by a slow movement toward the northwest. The remainder of the guidance favors a northwestward or north-northwestward turn between 36-48 h, with that motion continuing through the end of the forecast period. The new track forecast follows the latter scenario in anticipation that the center will try to follow convective bursts displaced to the north by southerly shear. The new forecast track is again adjusted west of the previous track, but it lies to the east of the HCCA corrected consensus and the Google DeepMind ensemble mean. Simon's small size makes it susceptible to intensity fluctuations based on the state of its compact inner core and small changes in the environmental conditions. The current northerly shear is forecast to diminish during the next 12-24 h, which may allow some modest re-intensification. By 36 h, increasing southerly to southwesterly upper-level flow between the trough to the northwest and Tropical Storm Trudy to the southeast should cause significant shear and aid in the entrainment of dry air. This should cause steady weakening, with Simon expected to weaken to a tropical storm as it approaches Baja California Sur. The system is likely to decay to a remnant low by 120 h as the shear and dry air cause the convection to dissipate. Simon continues to be a challenging storm to forecast, and confidence remains lower than normal given the weak steering, proximity to land, very small size, and significant model spread. Key Messages: 1. While Simon is no longer expected to bring hurricane conditions to Las Islas Marias, interests in west-central Mexico and Baja California Sur should continue to closely monitor the latest updates. Watches or warnings could be required for portions of Baja California Sur over the next day or two. 2. Large swells will likely affect portions of the coast of west-central Mexico and Baja California Sur over the next several days. These swells could cause life-threatening surf and rip current conditions. FORECAST POSITIONS AND MAX WINDS INIT 14/1500Z 19.7N 108.1W 80 KT 90 MPH 12H 15/0000Z 19.5N 108.3W 85 KT 100 MPH 24H 15/1200Z 19.3N 108.3W 85 KT 100 MPH 36H 16/0000Z 19.2N 108.3W 80 KT 90 MPH 48H 16/1200Z 19.9N 108.7W 75 KT 85 MPH 60H 17/0000Z 21.2N 109.7W 65 KT 75 MPH 72H 17/1200Z 22.6N 110.6W 50 KT 60 MPH 96H 18/1200Z 24.5N 112.2W 35 KT 40 MPH 120H 19/1200Z 26.9N 113.6W 25 KT 30 MPH...POST-TROP/REMNT LOW $$ Forecaster Beven  229 WTPZ45 KNHC 142055 TCDEP5 Hurricane Simon Discussion Number 30 NWS National Hurricane Center Miami FL EP202026 200 PM MST Wed Oct 14 2026 Simon is showing how small tropical cyclones can undergo rapid weakening as well as rapid intensification. A synthetic aperture radar (SAR) overpass near 13Z showed winds in the eyewall of 65-75 kt, suggesting that the intensity in the previous advisory was too high. An Air Force Reserve Hurricane Hunter aircraft has just reported that the storm is now weaker, with no hurricane-force winds present so far at 700 mb. The central pressure is near 989 mb based on a dropsonde with a surface pressure of 993 mb and surface winds of 41 kt. The initial intensity is reduced to 65 kt based mainly on the central pressure, and it is likely that this is generous. The aircraft reported a 16-nm wide eye open to the southwest and a larger radius of maximum wind than shown by the earlier SAR data. The hurricane continues drifting southwest or 235/3 kt. For the next day or so, Simon should continue drifting southwestward or southward in an area of light steering currents, with the center remaining well offshore. After that time, there remains some spread in the track guidance models. While all of the global models agree that a mid- to upper-level trough should form west of Baja California near and after 48 h, there remains disagreement on how this will affect Simon's track. The HAFS models keep the cyclone moving southward through 72 h, while the GFS model does not show any northward turn until 48 h. The remainder of the guidance forecasts a turn toward the northwest or north-northwest around 36 h, with that motion continuing through the end of the forecast period. The new track forecast follows the latter scenario in anticipation that the center will try to follow convective bursts displaced to the north by southerly shear. Overall, the track guidance envelope has shifted westward since the previous advisory, and so has the track forecast. Simon is currently experiencing light to moderate northerly shear and dry air entrainment, and this combination has at least temporarily disrupted the eyewall convection. The shear is likely to subside during the next 6-18 h, and based on this the intensity forecast keeps the cyclone as a minimal hurricane. After 36 h, increasing southerly and southwesterly upper-level winds between the trough to the northwest and Tropical Storm Trudy to the southeast should cause significant shear over Simon. The intensity forecast shows steady weakening during this time, and there is a possibility that Simon could weaken faster and dissipate sooner than currently forecast. Key Messages: 1. Interests in Baja California Sur should continue to closely monitor the latest updates. Watches or warnings could be required for portions of Baja California Sur over the next day or two. 2. Large swells will likely affect portions of the coast of west-central Mexico and Baja California Sur over the next several days. These swells could cause life-threatening surf and rip current conditions. FORECAST POSITIONS AND MAX WINDS INIT 14/2100Z 19.3N 108.3W 65 KT 75 MPH 12H 15/0600Z 19.2N 108.5W 65 KT 75 MPH 24H 15/1800Z 19.1N 108.4W 65 KT 75 MPH 36H 16/0600Z 19.5N 108.6W 65 KT 75 MPH 48H 16/1800Z 20.3N 109.5W 60 KT 70 MPH 60H 17/0600Z 21.5N 110.5W 55 KT 65 MPH 72H 17/1800Z 22.8N 111.5W 45 KT 50 MPH 96H 18/1800Z 24.9N 113.2W 30 KT 35 MPH 120H 19/1800Z 26.7N 114.2W 25 KT 30 MPH...POST-TROP/REMNT LOW $$ Forecaster Beven  103 WTPZ45 KNHC 150232 TCDEP5 Tropical Storm Simon Discussion Number 31 NWS National Hurricane Center Miami FL EP202026 800 PM MST Wed Oct 14 2026 Simon remains a tiny storm. The earlier Air Force Hurricane Hunter data along with an ASCAT-C pass indicate that the tropical- storm-force wind field is very small, only extending up to 30 n mi from the center. The last pass of the aircraft through the center suggested that Simon has fallen below hurricane strength, and the pressure has risen to about 991 mb. The initial intensity is estimated to be around 55 kt based on a combination of the aircraft data and various satellite fixes. Satellite images show that Simon is producing a concentrated area of deep convection over the center that has been increasing in coverage over the past few hours. The compact storm is moving southwestward at about 4 kt. The models suggest that Simon will move even slower or possibly stall over the next day or so as it remains caught in weak steering currents. However, a turn to the northwest seems likely on Friday when the system moves on the east side of a deep-layer cut off low. The NHC track forecast has been nudged to the left of the previous one, toward the latest HCCA and GDMI guidance. Simon has weakened at a rapid rate of about 40 kt over the past 24 hours. This highlights how challenging it is to predict intensity changes in very compact systems like this one. The environmental conditions appear generally favorable for the next 12 to 24 hours, so little change in strength is predicted in the short term. However, after that time, a notable increase in southwesterly vertical wind shear and intrusion of dry air should cause the system to decay. This forecast is quite a bit lower than the previous one given the lower initial intensity and trending toward the middle of the guidance envelope. In fact, it would not be surprising if Simon weakens faster than shown here. Key Messages: 1. Interests in Baja California Sur should continue to closely monitor the latest updates as Simon is expected to pass near or west of that area this weekend. 2. Large swells will likely affect portions of the coast of west-central Mexico and Baja California Sur over the next few days. These swells could cause life-threatening surf and rip current conditions. FORECAST POSITIONS AND MAX WINDS INIT 15/0300Z 19.1N 108.6W 55 KT 65 MPH 12H 15/1200Z 19.0N 108.5W 55 KT 65 MPH 24H 16/0000Z 19.1N 108.6W 50 KT 60 MPH 36H 16/1200Z 19.7N 109.1W 45 KT 50 MPH 48H 17/0000Z 20.8N 110.3W 40 KT 45 MPH 60H 17/1200Z 21.7N 111.2W 35 KT 40 MPH 72H 18/0000Z 22.8N 112.3W 30 KT 35 MPH 96H 19/0000Z 24.6N 113.6W 25 KT 30 MPH...POST-TROP/REMNT LOW 120H 20/0000Z 26.6N 114.8W 20 KT 25 MPH...POST-TROP/REMNT LOW $$ Forecaster Cangialosi  116 WTPZ45 KNHC 151443 TCDEP5 Tropical Storm Simon Discussion Number 33 NWS National Hurricane Center Miami FL EP202026 800 AM MST Thu Oct 15 2026 First light visible imagery, along with GPM and AMSR-3 microwave data, show that the convective organization of Simon has changed a bit, with the main convection now in a band to the west of the center. The various subjective and objective satellite intensity estimates are in the 40-55 kt range and have not changed much during the past 6 h. Based on this, the initial intensity remains a possibly generous 50 kt. The microwave overpasses suggest the center of Simon is a little to the east of the previous advisory position, and it appears that the cyclone may be making a small loop in its track. Little motion is expected for the next 12 h or so as Simon remains embedded in an area of weak steering currents. After that time, a mid- to upper-level low is forecast to form near or west of the northern Baja California Peninsula while a weak mid-level ridge develops over northern and central Mexico. This should cause Simon to move northwestward near, but west of, the coast of Baja California Sur, and this motion is expected to continue until the system dissipates. The current track guidance is in better agreement in both direction and speed that it was 24 h ago, and the new forecast track lies near the center of the guidance envelope. The new forecast is a little to the east of the previous forecast through 60 h based mainly on the initial position, and after that it is close to the previous forecast. Given the new track forecast and the small size of Simon, wind watches are not needed for Baja California Sur at this time. The shear over Simon has decreased since yesterday, and it should remain light for the next 12-18 h. However, the storm is embedded is a dry air mass, so it likely will not be able to take advantage of the decreased shear. After 18 h, southerly and southwesterly upper-level winds are forecast to increase between the trough to the northwest of Simon and Hurricane Trudy to the southeast. This will result in strong shear over Simon that should cause the cyclone to weaken. The intensity forecast shows the system becoming a remnant low pressure area by 72 h and dissipating completely by 120 h, and global model guidance suggests these events could happen earlier than currently forecast. Key Messages: 1. Interests in Baja California Sur should continue to closely monitor the latest updates as Simon is expected to pass near or west of that area this weekend. 2. Large swells will likely affect portions of the coast of west-central Mexico and Baja California Sur over the next couple of days. These swells could cause life-threatening surf and rip current conditions. FORECAST POSITIONS AND MAX WINDS INIT 15/1500Z 19.2N 108.1W 50 KT 60 MPH 12H 16/0000Z 19.5N 108.1W 45 KT 50 MPH 24H 16/1200Z 20.2N 108.8W 45 KT 50 MPH 36H 17/0000Z 21.1N 110.0W 40 KT 45 MPH 48H 17/1200Z 21.9N 111.3W 35 KT 40 MPH 60H 18/0000Z 22.9N 112.6W 30 KT 35 MPH 72H 18/1200Z 24.0N 113.6W 25 KT 30 MPH...POST-TROP/REMNT LOW 96H 19/1200Z 26.8N 114.4W 20 KT 25 MPH...POST-TROP/REMNT LOW 120H 20/1200Z...DISSIPATED $$ Forecaster Beven  795 WTPZ45 KNHC 152043 TCDEP5 Tropical Storm Simon Discussion Number 34 NWS National Hurricane Center Miami FL EP202026 200 PM MST Thu Oct 15 2026 Simon continues to produce an area of deep convection, though this activity has lacked a ton of organization today, and appears to still be displaced to the west of the center of circulation. A RCM-2 synthetic aperture radar (SAR) pass that became available after the prior advisory indicated that most of this convective activity was also occurring outside of its radius of maximum winds, and has done little to aid the small circulation. In fact, the peak winds retrieved from the SAR was only 47 kt. This information, combined with a Metop-B scatterometer pass that had a peak wind of 39 kt is justification to bring Simon's intensity down to 45 kt this advisory, and this may still be generous. Simon has been drifting rather aimlessly today, and my best guess at an estimated motion is 320/1 kt. It has been a tough few days trying to forecast Simon's track, but the model guidance this cycle is finally coming into better agreement showing that as Simon becomes a more vertically shallow cyclone, it will primarily be steered by the low-level flow. To that end, a weak low-level trough is forecast to drop equatorward to the west of Simon as a strong pressure gradient develops over northern Mexico as surface ridging builds in behind a frontal boundary. This flow should help to finally draw Simon back to the northwest with a speed up in its forward motion. The latest NHC track forecast is shifted once again a little further west but also faster, following the latest trends in the reliable HFIP Corrected Consensus Approach (HCCA) and Google DeepMind ensemble mean (GDMI). While the shear over Simon is currently low, it has not taken advantage of these more favorable conditions, likely due to the proximity of dry air preventing the convection from organizing. The vertical wind shear is soon expected to increase significantly out of the southwest as a deep-layer trough located over the southwestern United States cuts off and retrogrades back westward. Simon has already been sensitive to less than pristine conditions, and this increase in shear will likely be the storm's demise. The latest NHC forecast now shows gradual weakening continuing over the next 24-36 h, with Simon becoming a remnant low in 48 h, and fully dissipating in 72 h. If the latest ECMWF forecast is correct, this could occur sooner than forecasted here. FORECAST POSITIONS AND MAX WINDS INIT 15/2100Z 19.3N 108.2W 45 KT 50 MPH 12H 16/0600Z 19.8N 108.7W 40 KT 45 MPH 24H 16/1800Z 20.8N 110.0W 35 KT 40 MPH 36H 17/0600Z 22.0N 111.9W 30 KT 35 MPH 48H 17/1800Z 23.1N 113.6W 25 KT 30 MPH...POST-TROP/REMNT LOW 60H 18/0600Z 24.5N 115.0W 20 KT 25 MPH...POST-TROP/REMNT LOW 72H 18/1800Z...DISSIPATED $$ Forecaster Papin  407 WTPZ45 KNHC 160240 TCDEP5 Tropical Storm Simon Discussion Number 35 NWS National Hurricane Center Miami FL EP202026 800 PM MST Thu Oct 15 2026 Simon is gradually weakening. The compact storm is producing a limited area of convection that has been losing organization over the past several hours. The initial intensity is lowered to 40 kt, which is based on a blend of the latest satellite estimates and in general agreement with the earlier ASCAT pass. Simon remains tiny, with its associated tropical-storm-force winds only extending up to 40 n mi from the center. The storm continues to meander in weak steering currents. However, the models have finally come into fair agreement that a general northwestward motion should begin later tonight or tomorrow, and continue through the weekend when the system moves in the flow between a low-level trough to its west and a ridge to its east. This motion should bring the weak and shallow system to the west of the Baja California Peninsula over the weekend. Increasing southwesterly vertical wind shear and intrusions of dry air should cause Simon to continue to weaken over the next few days. Based on the model guidance and the hostile environmental conditions, Simon is now expected to become a remnant low in about 36 hours and dissipate in two or three days. FORECAST POSITIONS AND MAX WINDS INIT 16/0300Z 19.5N 108.5W 40 KT 45 MPH 12H 16/1200Z 20.1N 109.1W 35 KT 40 MPH 24H 17/0000Z 21.2N 110.7W 30 KT 35 MPH 36H 17/1200Z 22.1N 112.4W 25 KT 30 MPH...POST-TROP/REMNT LOW 48H 18/0000Z 23.2N 114.0W 20 KT 25 MPH...POST-TROP/REMNT LOW 60H 18/1200Z...DISSIPATED $$ Forecaster Cangialosi  829 WTPZ45 KNHC 161457 TCDEP5 Tropical Storm Simon Discussion Number 37 NWS National Hurricane Center Miami FL EP202026 800 AM MST Fri Oct 16 2026 Southwesterly vertical wind shear and dry mid-level air are taking a toll on Simon this morning. An earlier AMSR-3 microwave pass indicated that the mid-level center was displaced to the northeast of the low-level center, a trend also reflected in bursts of deep convection to the north and east of the center over the past several hours. The pass also suggested that the low-level center was slightly farther north than previously estimated, and the initial position was adjusted accordingly. The latest TAFB Dvorak intensity estimate was 2.0/30 kt. However, convective organization has changed little, so the intensity is maintained at 35 kt for this advisory. Simon is moving northwestward at 315/8 kt. Given the storm's shallow nature, its motion is being steered by the low- and mid-level flow, characterized by troughing to the west and a mid-level ridge to the northeast. This general motion is expected to continue over the next 24-36 h, bringing Simon parallel to the coast of Baja California Sur. Following the northward adjustment of the initial position, the latest NHC track forecast has been shifted slightly to the right of the previous forecast and lies near the corrected consensus (HCCA) track. Despite moving over very warm waters (28-30 C), significant southwesterly wind shear and increasingly dry mid-level air are expected to support continued weakening. In fact, simulated satellite imagery from the ECMWF and GFS suggest that Simon may struggle to maintain organized deep convection by late tonight. The official forecast calls for Simon to become a post-tropical remnant low within 24 h, though this transition may occur sooner. Dissipation is expected by 48 h. FORECAST POSITIONS AND MAX WINDS INIT 16/1500Z 20.6N 109.5W 35 KT 40 MPH 12H 17/0000Z 21.6N 110.9W 30 KT 35 MPH 24H 17/1200Z 22.7N 112.7W 25 KT 30 MPH...POST-TROP/REMNT LOW 36H 18/0000Z 24.0N 114.6W 25 KT 30 MPH...POST-TROP/REMNT LOW 48H 18/1200Z...DISSIPATED $$ Forecaster Adams  884 WTPZ45 KNHC 162035 TCDEP5 Remnants Of Simon Discussion Number 38 NWS National Hurricane Center Miami FL EP202026 200 PM MST Fri Oct 16 2026 Convection associated with Simon has rapidly diminished today. A recent scatterometer pass indicated that Simon no longer has a well-defined low-level center, and as a result, no longer meets the criteria for classification as a tropical cyclone. Therefore, this will be the final NHC advisory on Simon. The initial intensity is estimated at 30 kt. The remnants are expected to move northwestward today, steered by the low- and mid-level flow between a trough to the west and a mid-level ridge to the northeast. This motion should keep the remnants moving parallel to the coast of Baja California Sur. Dissipation is expected by late tonight or early tomorrow morning. For additional information on the remnants of Simon please see High Seas Forecasts issued by the National Weather Service, under AWIPS header NFDHSFEPI, WMO header FZPN01 KWBC, and on the web at ocean.weather.gov/shtml/NFDHSFEPI.php FORECAST POSITIONS AND MAX WINDS INIT 16/2100Z 21.5N 110.3W 30 KT 35 MPH...REMNANTS OF SIMON 12H 17/0600Z...DISSIPATED $$ Forecaster Adams