FXUS66 KPQR 291745 AFDPQR Area Forecast Discussion National Weather Service Portland OR 1045 AM PDT Sat Mar 29 2025 .UPDATED AVIATION DISCUSSION... && .SYNOPSIS...Active weather will continue today, with cool, near normal temperatures and persistent showers. Saturday night into Sunday a brief break in the precipitation as well as a slight warming trend is expected as a shortwave ridge quickly moves across the forecast area. By thee start of the upcoming week, a broad area of low pressure will bring a return of cooler temperatures, rain and Cascade snow by late Sunday night/Monday and these conditions look to persist through the upcoming week. && .DISCUSSION...Today through Friday...The trailing end of the low pressure system will finally be pushed out through this afternoon. The low will be replaced by a shortwave ridge which will quickly be replaced by another low pressure system by Sunday evening/Monday. What this means is that light showers will continue to dissipate through the afternoon, with dry and warmer weather is expected by tonight. Sunday will start off as slightly warmer and drier than the previous few days, but this will be short lived as the next major low will bring another round of cooler temperatures and widespread showers across the forecast area through all of next week. The system on Sunday night/Monday is a rather broad, vertically stacked low, with the surface low expected to be around 985 mb and centered around 45.75N/136.40W on Monday. This low will slowly weaken and travel southeastward through the upcoming week, with models showing landfall in-between Florence, OR and the OR/CA border. As this low moves southeastward, it will send multiple fronts across the region. This will result in south/southeasterly flow, that along with moderate warming and a moisture latent atmosphere will result in around a 10-20% probability for thunderstorms come Monday afternoon and continue through the late Monday evening. Cool and moist conditions will continue as the low continues to trudge southeastward and will bring widespread precipitation along with 850 mb temperatures dipping down towards -1C to -4C. This will result in a lowering of snow levels and the combination of lowering snow levels and precipitation could easily bring 6-11 inches of new snow to the Cascades. Current guidance is showing 6-11 inches or so, every 24 hours stating on Monday and continuing through Thursday for elevations above 2500-3000 ft. The current track of the low the focus of the snow will be more towards the Lane and Linn County Cascades. There is also a 10-20% probability of elevations above 5000 ft seeing snow accumulation around 10-12 inches for the same region. Overall, expect daytime highs to be near normal (50s and 60s) for the forecast area, with Sunday expected to be the warmest through the upcoming week. Saturday into Sunday evening will be dry, but precipitation returns by the start of next week. Also, cooler temperatures are on deck for the start of next week and that could bring Advisory level snowfall (6-11 inches) to the Oregon Cascades Monday through Thursday. Early ensemble guidance shows snow levels falling to around 2000-3500 ft, and mountain snow can be expected at times throughout next week. Currently evaluating potential for Winter Weather Advisory-level snow in the mountains with the initial front, particularly in the Lane County Cascades. We will continue to monitor model output as this is still 3 to 5 days out and could easily change. /42 && .AVIATION...Overall conditions remain primarily VFR through the TAF period. A weak shortwave ridge is expected to progress overhead this afternoon helping to dissipate any lingering showers over the interior lowlands and keep any additional activity more confined to the coast/coast range and Cascades the remainder of the day. Showers attempting to drift off the coast range may end up in the vicinity of KHIO however confidence is high showers/rain won't be a prevailing condition. The overall flow currently shifts more northerly late this afternoon and evening before turning easterly overnight. Winds generally remain less than 5-10 knots with KTTD the lone exception due to easterly winds through the Columbia Gorge increasing Sunday morning; gusts 20-25 knots locally. PDX AND APPROACHES...Mostly dry conditions with VFR CIGs/VIS continue through the day outside of a 15% change for a quick-hitting shower. Any nearby showers, especially before 19-20z could knock CIGS to high end MVFR. South to southwest winds less than 10 kts shifting northerly after 23z Sat to 02z Sunday, finally ending up easterly by 09-11z Sunday. -Schuldt && .MARINE...The surface trough pushed inland late Friday night, and winds and waves are weakening on the back side of this trough. Southwest winds will continue weakening through Saturday as weak high pressure moves over the waters. Winds turn offshore late Saturday into Sunday morning with locally breezy winds through coastal gaps. Winds then turn southerly by Sunday afternoon and increase through Sunday night as another frontal system approaches. There is about a 40-60% chance of low- end gale force wind gusts for Sunday night into Monday morning. More uncertainty into early next week as to where the surface low tracks, but confidence is high for at least Small Craft wind gusts over 21 kts. Seas have fallen to around 9 to 11 feet at 10 to 11 seconds, and will remain here through Saturday morning. A Small Craft Advisory is in effect through 11 AM Saturday. Seas should continue to subside through the weekend, falling to around 5 to 6 ft on Sunday. Seas will build again into the low teens late Sunday night into early next week in response to the approaching weather system and increasing southwesterly winds. -DH/HEC && .PQR WATCHES/WARNINGS/ADVISORIES... OR...None. WA...None. PZ...Small Craft Advisory until 11 AM PDT this morning for PZZ251>253-271>273. && $$ www.weather.gov/portland Interact with us via social media: www.facebook.com/NWSPortland x.com/NWSPortland