Area Forecast Discussion
Issued by NWS Portland, OR
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Issued by NWS Portland, OR
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-- Discussion containing changed information from previous version are highlighted. --178 FXUS66 KPQR 101114 AFDPQR Area Forecast Discussion National Weather Service Portland OR 314 AM PST Mon Nov 10 2025 .SYNOPSIS...-- Changed Discussion --A weak shortwave trough will bring light showers and increased low to mid-level clouds to the region. Drier weather briefly returns on Tuesday as high pressure builds. A pattern change to cooler and wetter weather returns on Wednesday. Snow levels fall Thursday to Friday, returning chances for snow at the Cascade passes. Active weather continues into the weekend.-- End Changed Discussion --&& .SHORT TERM...-- Changed Discussion --Today through Tuesday night...Radar and satellite imagery as of early Monday morning depicts mid to high level clouds moving into northwest Oregon and southwest Washington as a weak front brushes the region. Prior to these clouds moving in, clear skies, calm winds, and a moist surface supported the development of dense fog in the southern Willamette Valley. Based on surface observations, dense fog is resulting in visibility of one quarter mile or less in this area. Therefore, a Dense Fog Advisory has been issued for the southern Willamette Valley including Eugene, Creswell, and Cottage Grove through 10 AM this morning. If commuting, make sure to slow down, use your low beam headlights, and leave plenty of distance ahead of you. Circling back to the weak front that`s moving in, some light showers have begun along the north OR and south WA coast, and hi-res guidance suggests that these showers will gradually spread inland this morning. Since this weak front is tracking mostly to the north of us, most of the rain is being directed toward western Washington and southern British Columbia. Chances for even receiving any measurable rain today (0.01" or more) is only 30-50% across the Willamette Valley and southwest WA lowlands based on the REFS. The wettest areas today would likely be along the south WA coast, and north OR/south WA Cascades and foothills where chances for receiving 0.10" of rain or more are around 20-40%. Easterly winds through the Columbia River Gorge have finally begun to weaken as the pressure gradient from Troutdale (KTTD) to The Dalles (KDLS) has eased to about -1 mb. Expect winds today to be out of the south/southwest around 5 mph or less, shifting more northwesterly this evening as weak surface high pressure builds. A shortwave ridge builds on Tuesday, briefly returning drier conditions. However, an active weather pattern is in store for the remainder of the week, which will maintain onshore flow with widespread precipitation and cooler temperatures (see long term discussion). -10-- End Changed Discussion --&& .LONG TERM...-- Changed Discussion --Wednesday through Sunday...A deep upper level trough over the NE Pacific will approach the Pacific Northwest late Tuesday night into early Wednesday morning. A cold front associated with this upper trough will push through the region and bring widespread rain across northwest Oregon and southwest Washington by Wednesday afternoon. There still remains uncertainty with the exact track and strength of the low, and thus precipitation amounts. For now, chances for 24 hour (4 PM Wednesday to 4 PM Thursday) rain totals to exceed 1 inch are around 15-30% across interior lowland valleys, and 50-70% along the coast and Coast Range. Once this cold front pushes through, it will bring much cooler air to the region on Thursday. Cooler air aloft will support a more unstable atmosphere and thus lead to potential convection. There is currently a 10-20% chance for thunderstorms on Thursday west of the Cascades, with the highest chances along the coast. Any passing thunderstorms could produce lightning, heavy downpours, gusty outflow winds, and small hail. The majority of ensemble guidance also suggest that 850 mb (5000 ft) temperatures will fall to around -1 to -4 deg C Thursday to Friday, which would result in snow levels falling to pass level in the Cascades. Current guidance suggests a 70-80% chance that 48-hour snow totals between 4 AM Thursday to 4 AM Saturday exceeds 6 inches at Santiam and Willamette Passes, while chances are lower around 40-50% at Highway 26 near Government Camp. Those traveling to the Cascades at the end of the week should be sure to monitor the forecast and check on road conditions via ODOT/WSDOT before heading out. Heading into Saturday, warmer air will be introduced as a warm front from another system approaches the Pacific Northwest. This will briefly bring snow levels up above pass-level and maintain wet weather through the weekend. -10-- End Changed Discussion --&& .AVIATION...-- Changed Discussion --BKN/SCT high clouds continue to spread across northwest Oregon as a weak front moves through the region. CIGs have fallen to IFR/MVFR along the coast with this front, and there is high confidence (>90% chance) that this trend will continue along the coast through 20-22z Mon. Ahead of the high cloud cover associated with the front, areas of fog/mist and low stratus have developed across parts of the central and southern Willamette Valley, bringing LIFR/IFR CIGs and VIS. This trend continues until around 12-13z Mon when the front makes its way into the Valley and brings more showers and mixing. This mixing will help dissipate any fog and improve VIS and CIGs to MVFR/low-end VFR thresholds. Guidance suggests a 60-80% chance for MVFR CIGs with the frontal passage between 12-18z Mon for the northern Valley, and 18z Mon-00z Tue for the central and southern Valley. After 00z Tue, conditions begin to trend more VFR for most terminals as the front exits the region, but coastal terminals maintain a 30-50% chance for IFR/MVFR CIGs. Easterly winds around 15 kt with gusts up to 20 kt continue through the Columbia River Gorge and eastern Portland Metro (KTTD) as of early Monday morning, however, pressure gradients between KTTD and KDLS are forecast to gradually ease throughout the morning. This will weaken easterly winds. Elsewhere, winds today are generally southerly to southwesterly around 5 kt or less, turning more northwesterly in the afternoon. KPDX AND APPROACHES...VFR conditions until 15-17z Mon when chances for MVFR CIGs increase to 50-70% with the frontal passage. After 20-21z Mon, expect conditions to improve to VFR as the front exits the region. Easterly winds less than 5 kt today, turning more northwesterly this afternoon/evening. -10-- End Changed Discussion --&& .MARINE...-- Changed Discussion --Winds as of early Monday morning are southerly to southwesterly around 5-10 kt as a weak front pushes through the waters. Expect winds to gradually shift westerly this morning as the front progresses inland. By this afternoon, weak high pressure will rebuild and winds turn northerly. Seas generally remain 7-9 ft at 11 seconds today. Benign marine conditions continue through Tuesday night with variable winds and gusts remaining around 10 kt or less. High confidence (>95% chance) that seas remain below 10 ft through early Wednesday morning. The next low pressure system in the NE Pacific will return breezy southerly winds and building seas Wednesday into Thursday, with high confidence for another period of conditions hazardous to small craft. As this system swings a front through the waters, we`ll likely (60-80% chance) see frequent southerly wind gusts exceeding 21 kt and a >90% chance that seas build above 10 ft by Wednesday night. There is also a 40-60% chance for isolated gale-force wind gusts greater than 34 kt Wednesday-Thursday, with the highest chances across the outer waters beyond 20-30 NM. Active weather continues into the end of the week with additional systems moving through the waters. -10-- End Changed Discussion --&& .PQR WATCHES/WARNINGS/ADVISORIES... OR...None. WA...None. PZ...None. && $$ www.weather.gov/portland Interact with us via social media: www.facebook.com/NWSPortland x.com/NWSPortland