991 AXNT20 KNHC 231552 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1815 UTC Sun Aug 23 2026 Tropical Weather Discussion for North America, Central America Gulf of America, Caribbean Sea, northern sections of South America, and Atlantic Ocean to the African coast from the Equator to 31N. The following information is based on satellite imagery, weather observations, radar and meteorological analysis. Based on 1200 UTC surface analysis and satellite imagery through 1300 UTC. ...TROPICAL WAVES... An eastern Atlantic tropical wave has its axis along 33W south of 19N, moving quickly westward at 20 to 25 kt. Scattered moderate convection is noted from 04N to 09N between 31W and 39W, and from 11N to 13N between 34W and 36W. A central Atlantic tropical wave has its axis along 53W south of 20N, moving westward at around 20 kt. Scattered moderate convection is near the northern portion of the wave from 19N to 23N between 47W and 53W. This wave was seen nicely at the surface by recent ASCAT scatterometer data. An eastern Caribbean Sea tropical wave has its axis along 66W south of 20N along eastern Puerto Rico to north-central Venezuela, moving quickly westward at 20 to 25 kt. A small patch of scattered moderate convection is noted from 14N to 16N between 67W and 71W. A northwestern Caribbean tropical wave has its axis near 86W south of 21N from near the Yucatan Channel to central Honduras, moving westward at around 10 kt. Only isolated to widely scattered showers are near the wave axis. To the south over the far southwestern section of the Caribbean basin, scattered to numerous moderate to strong convection is noted just behind the wave and near the eastern extend of the eastern Pacific monsoon trough from 06N to 13N between 79W and 89W. ...MONSOON TROUGH/ITCZ... The monsoon trough axis enters the Atlantic through the coast of Africa near 16N16W and continues southwestward to 06N42W. The ITCZ extends from 06N42W to 07N51W, then resumes west of a tropical wave from 09N55W to the coast of Venezuela at 09N61W. Aside from the convection described in the section above, scattered moderate convection is noted from 13N to 17N between 19W and 24N approaching portions of the Cabo Verde Islands, and from 07N to 10N between 23W and 26W. This convection may be associated with or out ahead of the next tropical wave to emerge off the coast of Africa. ...GULF OF AMERICA... Relatively weak high pressure, anchored by a 1018 mb high center over the north-central Gulf at 27.5N90.5W, is generally allowing for anticyclonic light to gentle winds across the basin Slight seas are present throughout the basin per buoy observations. Scattered to numerous showers and thunderstorms remain are active over the Yucatan Peninsula and the southwestern Gulf offshore Veracruz, Mexico where a surface trough is present, and due to abundant upper moisture from the eastern Pacific which continues to advect eastward over southern Mexico. Isolated to widely scattered convection is also present near the coast of Florida just south of Apalachee Bay, and from offshore Tampa Bay west- southwestward about 300 nm, likely induced by a weak low-level trough. For the forecast, weak high pressure will remain centered over central Gulf through midweek, with the western Atlantic ridge building westward into the basin thereafter. This will maintain gentle to moderate winds and mainly slight seas through the week. A surface trough will generate fresh winds north and west of the Yucatan Peninsula in the early evenings through the period. The trough will push further offshore through the Bay of Campeche during the overnight hours. ...CARIBBEAN SEA... Please see the Tropical Waves section above for details on convection in the basin, mainly confined to the southwest portion. The pressure gradient associated to high pressure over the western Atlantic and relatively lower pressure in northern South America is sustaining fresh to locally strong trades primarily over the south-central Caribbean. Seas up to around 8 ft are with these trades. Moderate to fresh trades and moderate seas are elsewhere, except over the northwestern part of the Caribbean north of 20N, where light to gentle winds and slight to moderate seas are present. For the forecast, the pressure gradient between western Atlantic high pressure and low pressure in northern South America continue to maintain fresh to strong trades and resultant rough seas over the south-central Caribbean through the week. Elsewhere, mainly moderate to fresh trades and moderate seas will prevail, aside from light to gentle winds and slight seas in the NW part of the basin. Winds will occasionally increase through the week following passages of a series of relatively weak tropical waves that will quickly move west across the basin. ...ATLANTIC OCEAN... Low pressure of 1015 mb, Invest AL95, is centered near 28N60W. Some fresh to locally strong winds are found near this low, north of 28N between 55W and 60W. Scattered to numerous moderate isolated strong convection is present north of 23N between 49W and 62W. Elongated surface troughing extends from north of the area well offshore the Carolinas through 31N78W to near Fort Pierce, Florida. Some isolated to widely scattered showers and thunderstorms are seen on infrared satellite imagery from the northern Bahamas northward within 120-240 nm either side of the trough. To the east, a cold front extends from near the Iberian Peninsula southwestward through 31N16W to 29N26W to 1020 mb low pressure near 30N29W, then northwestward as a frontal trough. Limited convection is near these features. Rough seas are found north of the front. Across the remainder of the basin, high pressure weak ridging dominates with a 1020 high north of the area near 35N44W. Moderate to fresh trades are found from 10N to 22N north of the monsoon trough between the Cabo Verde ISlands and 42W, and in a belt from there to near the low pressure area, AL95. Winds are moderate or weaker across the remainder of the waters. Seas are slight north of 20N and west of 60W, and moderate across the remainder of the waters. For the forecast west of 55W, the low pressure of 1015 mb centered near 28N60W is forecast to drift northwest today, then accelerate northward and out of the basin Mon. There is a low chance of tropical development of this low over the next 48 hours. Otherwise, high pressure will maintain light to gentle winds N of 23N through the period. To the south, moderate to fresh trades will prevail, with locally strong winds pulsing at times offshore Hispaniola and into the Windward Passage. The northern portion of a tropical wave will move across the waters S of about 23N and E of the Bahamas early next week freshening the trades. By Wed, the northern portion of another tropical wave may move across the SE portion of the area, increasing the trades over those waters. $$ Lewitsky  004 AXPZ20 KNHC 231553 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Sun Aug 23 2026 Tropical Weather Discussion for the eastern Pacific Ocean from 03.4S to 30N, east of 120W including the Gulf of California, and from the Equator to 30N, between 120W and 140W. The following information is based on satellite imagery, weather observations, radar, and meteorological analysis. Based on 1200 UTC surface analysis and satellite imagery through 1500 UTC. ...SPECIAL FEATURES... Tropical Storm Iselle forms today well offshore of Mexico. It is centered near 15.3N 114.2W at 23/1500 UTC, moving west-northwest at 10 kt. Estimated minimum central pressure is 1003 mb. Maximum sustained wind speed is 40 kt with gusts to 50 kt. Numerous moderate to strong convection is noted within 180 nm W semicircle and 90 nm E semicircle of center. A northwestward motion is expected through Monday, followed by a gradual turn back toward the west- northwest on Tuesday. Some strengthening is forecast during the next couple of days, and Iselle could become a hurricane late Monday or early Tuesday. The outer periphery of Iselle will bring strong winds and rough seas to the Revillagigedo Islands today. Tropical storm conditions are possible today, and storm conditions are expected tonight. Please read the latest HIGH SEAS FORECAST issued by the National Hurricane Center at website - https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml and the latest Iselle NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. Central East Pacific (EP91): Disorganized showers and thunderstorms are persisting with a broad area of low pressure located well to the south-southwest of the southern tip of the Baja California Peninsula. Environmental conditions could support the development of a short-lived tropical depression during the next day or two before it interacts or merges with T.S. Iselle. This system has a medium chance for tropical cyclone formation through 48 hrs, and also through 7 days. Please refer to the latest NHC Tropical Weather Outlook at website: https://www.nhc.noaa.gov/text/MIATWOEP.shtml for more details on these systems. ...TROPICAL WAVES... A tropical wave is along 86W/87W from 04N to 20N moving westward at 15 kt. A cluster of moderate to isolated strong convection is noted from 10N to 12N between 80W and 85W. this convective activity is affecting southern Nicaragua and northern Costa Rica. A tropical wave is along 100W N of 04N to near Acapulco, Mexico, moving westward at 15 kt. Scattered moderate to isolated strong convection is observed from 10N to 16N between 96W and 105W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 09N84W to 07N100W to 15N110W to 10N123W to beyond 06N140W. Aside from the convection related to the tropical waves, Invest area EP91 and T.S. Iselle described above, scattered moderate to isolated strong convection can be found from 06N to 13N between 90W and 97W, and from 03N to 10N W of 130W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section for more information about recently upgraded T.S. Iselle and Invest area EP91. A ridge continues to dominate the offshore forecast waters of Baja California Norte supporting gentle to moderate NW winds and moderate seas. Winds and seas associated with the outer periphery of T.S. Iselle are reaching the Revillagigedo Islands. gentle to moderate Se to S winds are occurring in the Gulf of california with slight to moderate seas. The highest seas are near the entrance to the Gulf. Fresh to strong N gap winds are across the Gulf of Tehuantepec region and downwind to about 14N. Seas are up to 8 ft with these winds. For the forecast, Tropical Storm Iselle will move to 16.5N 115.6W this evening, 17.9N 117.2W Mon morning, strengthen to a hurricane near 19.3N 118.7W Mon evening, 20.5N 120.3W Tue morning, weaken to a tropical storm near 21.4N 121.9W Tue evening, and 22.0N 123.6W Wed morning. Iselle will change little in intensity as it moves to near 23.0N 127.2W early Thu. Fresh northerly gap winds will continue to pulse to strong speeds over the Gulf of Tehuantepec during the overnight into the early morning hours through the next several days, with seas occasionally building to 8 ft. A ridge will continue to dominate the offshore forecast waters of Baja California Norte today, supporting mainly gentle to moderate winds. Southerly wind flow will become fresh to locally strong over the north and central parts of the Gulf of California today. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Fresh to strong NE to E gap winds continue across the Papagayo region and downwind to near 91W, where seas are 6 to 8 ft. Moderate or weaker winds are found elsewhere, with moderate seas in S swell. For the forecast, high pressure will persist over the eastern Gulf of America and northwestern Caribbean into early next week, leading to fresh NE to E gap winds pulsing to strong speeds over the Papagayo region each evening and night. Moderate to fresh winds extending well downwind of Papagayo will impact the outer waters offshore of El Salvador and Guatemala through the middle of the week. South of the monsoon trough, gentle to locally moderate winds will persist through Wed night. Mainly moderate seas will prevail away from the Gulf of Papagayo through the forecast period. ...REMAINDER OF THE AREA... Please see the Special Features section for more information about recently upgraded T.S. Iselle and the Invest area EP91. High pressure of 1024 mb located near 42N133W extends a ridge southeastward into the northern forecast waters to offshore of Baja California Norte, supporting moderate to locally fresh NE to E winds from 10N to 26N W of 130W. Moderate or weaker winds and moderate seas in mixed swell prevail elsewhere. For the forecast, Another area of low pressure is expected to develop well south of the southern tip of the Baja California Peninsula during the middle portion of this week. Some slow development is expected thereafter, and a tropical depression could form by the end of the week while the system moves generally west-northwestward. This system has a medium chance for tropical cyclone formation through 7 days. $$ GR