138 FXUS66 KPQR 110447 AFDPQR Area Forecast Discussion...Updated Aviation National Weather Service Portland OR 947 PM PDT Thu Apr 10 2025 .SYNOPSIS...A cool weather pattern will maintain itself across the area through Saturday before the pendulum swings back to warm and dry Sunday through at least early next week. && .SHORT TERM...Through Saturday Night...A loop of radar and satellite imagery this afternoon shows a front moving west to east across northwest Oregon and southwest Washington. Rainfall amounts with the front have generally been less than a quarter of an inch so far. High resolution models and observations support that the bulk of the rain will shift east of the region by 6-8pm. The main impact from this front will be a return to cooler temperatures Friday and Saturday with valley high temperatures struggling to reach 60F. A reinforcing shortwave trough will clip the region Friday night. While there is a decent chance (20-50%) that some lower elevations get cold enough for frost Friday night, uncertainty surrounding the extent of cloud cover makes confidence low in picking out which areas will experience temperatures drop into the low to mid 30s at this point. We may need Frost Advisories for some zones, but confidence is not there yet. Ensembles agree shortwave ridging will begin to build into the region Saturday night. This should lead to clearing skies and decreasing winds across the region. This will set the stage for colder overnight low temperatures across the region with a 50-70% chance for temperatures to drop into at least the mid 30s away from the coast and inner Portland metro. Larger areas of frost appear much more likely as a result. Meanwhile, the upper Hood River Valley appears to have a very high chance (90%+) of experiencing freezing temperatures Saturday night so went ahead and issue a Freeze Watch to cover this hazard. /Neuman .LONG TERM...Sunday through Wednesday...Ensembles are in good agreement shortwave ridging will bring a warming trend Sunday into Monday. While Willamette Valley locations stand a 50:50 chance of hitting 70F Sunday, confidence is considerably higher for 70s to materialize on Monday with the probability of them occurring at 90% or higher at most sites in the Willamette Valley per the NBM. Uncertainty in the extended forecast does begin to grow towards Tuesday and Wednesday next week, but is still relatively limited. Most of the global ensemble members suggest ridging temporarily flattening and then returning with above average heights remaining over the region through the middle of next week. While temperatures appear most likely to cool Monday through Wednesday due to the flattening ridge, temperatures should still remain above average. With that said, there is ~10% of the global ensemble membership that bring a deeper shortwave trough into the northern Pacific Northwest that would result in a return to a cooler and wetter weather pattern. Given well more than majority of ensemble members suggest dry weather and mild temperatures continuing, kept the NBM forecast as is in the extended which keeps temperatures well above average and keeps mentionable (15% or higher) rain chances limited to our far northern zones where the aforementioned shortwave trough is most likely to clip. /Neuman && .AVIATION...Inland terminals currently experiencing VFR ceilings with an overcast deck around 5000 ft, while coastal terminals currently see MVFR cigs. Coastal terminals remain mixed VFR/MVFR cigs through around 15-18z Friday, though terminals further north (KAST) may see ceilings leaning more towards VFR. Inland, generally VFR conditions expected throughout the period, though a brief period overnight of 40-50% chance of low clouds developing in the Willamette Valley, particularly in the central/southern Valley. This could produce MVFR ceilings between 10-19z Friday. Winds currently fairly weak and variable under 5 kts throughout the area, but will begin picking up around 18z Fri out of the north. Gusts to 20-25 kts expected at that time. PDX AND APPROACHES...VFR conditions through the period, with a broken deck gradually rising from around 4000-5000 ft to 8000-1000 ft by the end of the TAF period. Winds currently weak and variable around 5 kts, increasing to 10 kts around 18z and shifting northerly at that time. /JLiu && .MARINE...A cold front that pushed across the waters is moving inland. The earlier Gale Force winds have subsided with Small Craft Advisory level wind gusts to 25 kt currently occurring across the waters. There is a good agreement among the weather models winds will continue to decrease through the evening hours as surface high pressure builds towards the waters. Seas have climbed quickly to near 10 ft across the waters with dominant periods of 6-7 seconds. While the decrease in winds will allow seas to subside, seas will remain particularly steep through the evening hours so will maintain a Small Craft Advisory to cover this hazard. A trailing westerly swell will push seas back up to near 10 ft Friday, particularly across the northern waters. A much weaker front will drop southeastward across the waters Friday night, but the odds for wind gusts climbing up towards 21-25 kt is less than 10%. There is high confidence high pressure will build over the Pacific Northwest and thermally induced lower pressure will develop over California and the southern Oregon coast late in the weekend. This will lead to a Summer-like wind pattern with building northerly winds across the waters during this time. Winds will generally be strongest off the central coast of Oregon and weakest off the south Washington coast during this time. Expect winds to peak across the inner waters during the late afternoon and evening hours, and gusty northerly winds to persist across the outer waters during the overnight hours. High pressure looks to gradually weaken next week, but there are few signals among the weather models of any major fronts crossing the waters that would produce Gale Force or higher winds. && .PQR WATCHES/WARNINGS/ADVISORIES... OR...Freeze Watch from late Saturday night through Sunday morning for ORZ121. WA...None. PZ...Small Craft Advisory until 3 AM PDT Friday for PZZ210-251>253- 271>273. && $$ www.weather.gov/portland Interact with us via social media: www.facebook.com/NWSPortland x.com/NWSPortland