Area Forecast Discussion
Issued by NWS Portland, OR
Issued by NWS Portland, OR
089 FXUS66 KPQR 040452 AFDPQR Area Forecast Discussion National Weather Service Portland OR 952 PM PDT Tue Jun 3 2025 .UPDATED AVIATION DISCUSSION... && .SYNOPSIS...This week, the Pacific Northwest (PacNW) will be under a northwest flow pattern, caught between a ridge of high pressure over the northeast Pacific and a trough over the Great Basin. Expect mostly dry weather and slightly above normal temperatures. As we head toward the weekend, temperatures will climb, with Sunday likely bringing the warmest conditions of the year so far. && .DISCUSSION...Now through Sunday...High pressure continues throughout the next few days, allowing for increasingly warm temperatures from Thursday onwards. Before then, cooler air being brought in from the northwest allows temperatures to stay relatively seasonable, bottoming out on Wednesday. On Wednesday afternoon, high temperatures will be right around 70 in the Willamette Valley and closer to the low 60s at the coast. On Thursday, ridging begins to fully start building in, and inland temperatures show a 60-80% chance of exceeding 80 degrees. From Thursday onwards, each afternoon climbs in temperature as upper air temps increase. Current models have temperatures peaking on Sunday afternoon, whenthere is a 50-80% chance of temperatures in the Willamette Valley exceeding 90 degrees. Temperatures in the Portland metro area will be a few degrees warmer than the rest of the Willamette Valley due to urban heat island effect. That said, there remains some degree of uncertainty regarding Sunday`s temperatures. A cooler scenario (NBM 10th percentile) shows inland temps in the mid to upper 80s, in the case that winds remain northwesterly during that time. In a warmer scenario (NBM 90th percentile), where winds shift northeasterly, bringing in inland warm air, temperatures push up to 100 degrees in the Willamette Valley, closer to 75-80 at the coast. In any case, there continues to be potential for a significant heat event with Major Heat Risk over this coming weekend. Throughout this period, winds peak in the afternoon with gusts up to 15-20 mph at times. /JLiu && .AVIATION...Broken marine stratus over the coastal waters has quickly evolved into a solid low overcast deck this evening bringing a mix of MVFR to IFR CIGs to coastal terminals. This marine layer will then deepen the rest of tonight, promoting patchy light drizzle along the north coast by 08-10z Wed. This is also when MVFR cigs should lower to mainly IFR at the coast, and roughly when MVFR cigs should develop over all inland terminals. Given a very weak weather disturbance moving overhead can`t rule out occasional drizzle/mist at Portland/Vancouver area terminals Wednesday morning as well - lower chances central and southern Willamette Valley. Low clouds will then remain in place through 20-23z Wed before scattering out and lifting thereafter, although confidence in the exact timing of the MVFR to VFR switch is low at this time as some guidance pushes this transition later into the afternoon (after 00z Thur). PDX AND APPROACHES...Clear skies will give way to low clouds with MVFR cigs by 08-09z Wed after which point expect occasional mist/drizzle through the morning hours. This cloud deck should gradually clear in the afternoon hours with higher confidence in VFR CIGs/VIS after 23z Wed-02z Thur. Winds generally stay less than 5-10 knots. -Schuldt && .MARINE...Not much change as a summer time pattern has settled in with high pressure persisting offshore through the week, resulting in persistent northerly winds. Northerly winds will be strongest during the afternoon and evening hours each day this week, especially over the central and southern waters where small craft advisory level wind gusts up to 25 kt are likely to occur each day from Tuesday through Sunday. The general sea state will continued to be dominated by northerly wind waves and a fresh northwesterly swell through Sunday with significant wave heights around 6 to 8 ft and a dominant wave period around 8 to 9 seconds. Expect seas to remain steep and choppy during the afternoon and evening hours when winds are strongest. -TK && .PQR WATCHES/WARNINGS/ADVISORIES... OR...None. WA...None. PZ...Small Craft Advisory until midnight PDT tonight for PZZ272-273. && $$ www.weather.gov/portland Interact with us via social media: www.facebook.com/NWSPortland x.com/NWSPortland