FXUS66 KPQR 240444 AAA AFDPQR Area Forecast Discussion...UPDATED National Weather Service Portland OR 944 PM PDT Sun Aug 23 2026 Updated Aviation Discussion .SYNOPSIS...Upper level ridging and low-level offshore flow develops Monday, continuing into Tuesday, bringing warmer and sunnier conditions with high temperatures in the mid 80s to lower 90s across the interior lowlands, warmest on Monday. Wildfire smoke will also begin to increase over the Columbia River Gorge, Upper Hood River Valley, and the greater Portland/Vancouver metro area Monday morning and then linger through Tuesday; however smoke is not expected to be dense for most locations. Onshore flow arrives by Wednesday and continues thereafter, which will clear any lingering smoke out of the area and bring relatively cooler temperatures through the end of the week and into the weekend. && .DISCUSSION...Tonight through Saturday Night...Water vapor satellite imagery reveals the upper level shortwave trough lifting across NE Washington into Canada this afternoon. Heights aloft will continue to increase through tonight allowing for clearing skies. As a ridge of high pressure builds aloft over the region, a surface thermal trough develops along the coast extending into western WA early Monday morning. This will allow for light offshore flow to develops, especially over the western slopes of the Cascades with east winds increasing through the Columbia River Gorge later Monday morning. Winds are not expected to be very strong, but gusts up to 25-30 mph will certainly be possible through the western gorge. Temperatures at 850 mb are also expected to rapidly rise to around 20C by Monday evening. Downsloping winds and afternoon mixing will therefore allow for surface temperatures to warm into the upper 80s to lower 90s across much of the inland lowlands, as well as through Cascade valleys, while temperatures at the coast will likely warm into the 70s before winds shift as sea-breezes occur early in the afternoon. This offshore flow will also cause wildfire smoke to begin to filter back down into the valleys, including into the Portland/Vancouver Metro area, Columbia River Gorge and Upper Hood River Valley. However, smoke is not expected to be dense for most locations. By Monday evening, the surface thermal trough is expected to shift east into the Willamette Valley, and potentially to the Cascade crest, allowing for onshore flow to return across much of the area. Lingering low pressure in the valley will likely allow for very light offshore flow to return over the Cascade foothills Monday night into early Tuesday. This will likely maintain elevated overnight temperatures in the lower to mid-60s where the easterly winds persist. A moderate risk of heat related illnesses will therefore exist Monday into Tuesday. Wildfire smoke is also likely to linger into Tuesday as well for northern portions of the forecast area. Early Tuesday, a shortwave trough will lift just offshore, skirting the coast, as a deeper upper level low in the Gulf of Alaska drops south. This should cause a southerly wind reversal to occur along the Oregon coast and into the Willamette Valley. Heights aloft still remain high with the axis of the upper level ridge over the Intermountain West, but 850 mb temps cool to around 16-17C. Still expecting Tuesday temperatures to warm into the mid to upper 80s (about 4-8 degrees above normal). By Tuesday evening, surface high pressure building along the coast will bring a strong marine push of westerly winds. Any lingering wildfire smoke should shift back east of the Cascades by Wednesday. Models and their ensembles are showing fairly good agreement that the upper level trough over the NE Pacific gradually pushes east over the Pacific NW Wednesday through Thursday, with troughing likely persisting over the region through the end of the week and into the weekend. There is high confidence that temperatures trend cooler to near or slightly below average. Confidence is low regarding precipitation, if any will occur later this week. But, if any rain does fall, it would most likely be very light. Best chances would be drizzle along the coast with a weak frontal passage Thursday morning; and again on Saturday, but PoP remains around 15% or less. /DH && .AVIATION...06Z TAFs...Generally VFR conditions under mostly clear skies across the airspace through around 15Z Monday. Coastal locations could see some MVFR to LIFR conditions developing along the coast from 08Z-18Z Monday, with higher probabilities of IFR/LIFR conditions impacting KONP. Could also see some MVFR conditions developing between KSLE and KEUG through the same time, but there is only a 10-25% chance of this occurring. Any lowered flight conditions should develop into VFR around 16Z-18Z Monday. North/northeast winds through the TAF period. Expect breezy winds gusting around of 20 kt at KONP. Around 18-20Z Monday, easterly winds around 8-11 kt are expected to develop at KTTD and KPDX as offshore winds develop through the Columbia River Gorge. The north/northeast winds will also push some wildfire smoke/haze into the Willamette Valley. Smoke/haze will have the potential reduce vertical and slantwise visibilities at times. In addition, temperatures are expected to warm into the lower 90s Monday afternoon at the inland TAF sites, so be aware of high density altitude which may reduce aircraft performance. KPDX AND APPROACHES...Generally VFR flight conditions through the TAF period. North/northeast winds through the TAF period with more easterly winds developing around 18-20Z Monday. Expect 8-11 kt to develop near and east of the terminal as easterly winds develop through the Columbia River Gorge. Smoke/haze will have the potential reduce vertical and slantwise visibilities at times. In addition, temperatures are expected to warm into the lower 90s Monday afternoon at the inland TAF sites, so be aware of high density altitude which may reduce aircraft performance. /42 && .MARINE...Northerly winds will gradually increase Sunday afternoon and evening as high pressure strengthens over the northeast Pacific. Gusty winds will develop over the waters, increasing from south to north from Florence to Cape Shoalwater. Wind gusts up to 25 kt are expected to develop Sunday evening over the southern and central waters, and over the northern waters Sunday night. These wind speeds will then persist through Monday afternoon/early evening before decreasing Monday night. Small Craft Advisories remain in effect from 5 PM Sunday to 5 PM Monday for the coastal waters from Florence north to Cape Falcon and from 11 PM Sunday to 8 PM Monday for the coastal waters north of Cape Falcon to Cape Shoalwater. Gusty north winds up to 25 kt are also expected for the Columbia River Bar starting at 8 AM Monday, which also has a Small Craft Advisory in effect. A southerly wind reversal arrives early Tuesday morning over the inner waters with gusts up to 15-20 kt expected by Tuesday afternoon. This will also bring increasing chances for marine fog beginning early Tuesday morning, especially over the inner waters. Visibilities may fall below 1 SM at times as the southerly winds develop and upwelling occurs. Aside from the increasing winds and potential marine fog, significant wave heights look to remain relatively low at around 3 to 5 ft through Friday. -23 && .PQR WATCHES/WARNINGS/ADVISORIES... OR...None. WA...None. PZ...Small Craft Advisory from 8 AM to 8 PM PDT Monday for PZZ210. Small Craft Advisory until 8 PM PDT Monday for PZZ251-271. Small Craft Advisory until 5 PM PDT Monday for PZZ252-253-272- 273. && $$ www.weather.gov/portland Interact with us via social media: www.facebook.com/NWSPortland x.com/NWSPortland