437 FXUS66 KPQR 092127 AAA AFDPQR Area Forecast Discussion National Weather Service Portland OR 227 PM PDT Mon Jun 9 2025 .SYNOPSIS...High pressure aloft will begin to weaken today, but not before supporting one final day of hazardous heat across inland areas while the coast begins to cool. Increasing onshore flow will see a cooling trend continue through the workweek. && .SHORT TERM...Now through Tuesday Night...Ridge axis has already passed east of the area, and one more day or potentially hazardous heat is expected the rest of this afternoon. Temperatures as of 2pm Monday are around 90 degrees for most of the Willamette Valley, with high temperatures this afternoon expected to settle around the mid 90s. The hottest temperatures are again likely from the Portland/Vancouver Metro east through the Columbia River Gorge to Hood River. The Heat Advisory currently in place continues through 10pm tonight as a result. Those sensitive to heat, and especially those without effective cooling and/or adequate hydration, may feel impacts from this level of heat. Those seeking relief in area lakes and rivers should also be aware that water temperatures are still very cold and hypothermia can occur despite the hot air temperatures. The coast sees cooler temperatures today, with an expected high between 65-70 degrees. Overnight temperatures tonight will be significantly cooler than last night as the ridge breaks down, with inland low temperatures in the mid 50s expected. Heading into Tuesday, increasing onshore flow and the ridge moving out of the area allows for a slightly cooler conditions during daytime hours. The Willamette Valley only sees a 0-10% chance of high temperatures exceeding 90 Tuesday afternoon, with expected values in the mid-80s. The coast looks even cooler, with a high around 60 degrees. The trend of cooling temperatures continues through the rest of the workweek as onshore northwesterly flow continues, bringing cooler air into the region. /JLiu .LONG TERM...Wednesday through Sunday...Ensemble guidance remains in good agreement that upper-level ridging will be replaced by weak troughing in the Pacific Northwest through the latter half of the week. Increased onshore flow will continue to see temperatures cool toward seasonal norms, with increasing confidence in highs in the 70s along I-5 & I-84 by Friday and Saturday while coastal areas see highs in the 50s to 60s. There is growing consensus that a closed upper low will track to the southeast from south-central Alaska toward the Haida Gwaii, while repeated shortwave impulses on its southern flank may bring chances for rainfall to the region by Friday or the weekend. At this lead time, global ensemble members suggest only very light potential rainfall amounts with any disturbance that does affect the region. -Picard && .AVIATION...Strong high pressure continues to support clear skies and VFR conditions across most of the region through the TAF period. Guidance depicts stratus redeveloping at the coastal terminals 03-06z Tue, bringing IFR conditions back to KAST and KONP through around 18z Tue. Another day of highs in the mid 90s could result in lower air density conditions at the inland terminals this afternoon. Winds will generally be out of the northwest between 5-10 kt at most sites but will gust as high as 20 kt at KONP through 03z Tue. PDX AND APPROACHES...VFR under clear skies through the period. Northwest winds around 8 kt, diminishing below 5 kt after 03z Tue. /CB && .MARINE...Little change in the forecast as surface high pressure centered well offshore maintains a northerly wind regime through the end of the week. Current observations show winds gusting to 20-25 kt over the coastal waters, with seas running 8-9 ft due to a combination of short period wind waves and building northwest swell. These conditions will maintain Small Craft Advisories through Tuesday and possibly beyond as combined seas generally remain in the 7-9 ft range for the next several days. /CB && .CLIMATE... Daily record high temperatures Monday, June 9: Portland:95 (1955) Hillsboro:95 (1955) McMinnville:95 (1924) Salem:96 (1955) Eugene: 91 (2015) Astoria:87 (1924) Tuesday, June 10: Portland:90 (1982) Hillsboro:91 (1932) McMinnville:91 (1909) Salem:93 (1940) Eugene: 90 (1940) Astoria:83 (1889) && .PQR WATCHES/WARNINGS/ADVISORIES... OR...Heat Advisory until 10 PM PDT this evening for ORZ108>125. WA...Heat Advisory until 10 PM PDT this evening for WAZ204>210. PZ...Small Craft Advisory until 6 PM PDT Tuesday for PZZ251>253- 271>273. && $$ www.weather.gov/portland Interact with us via social media: www.facebook.com/NWSPortland x.com/NWSPortland