370 FXUS66 KPQR 162122 AFDPQRArea Forecast Discussion National Weather Service Portland OR 222 PM PDT Tue Sep 16 2025
.SYNOPSIS...Dry, offshore flow will continue to subside through the evening. Onshore flow returns tonight as a weak front brushes the coast. A broader trough moving into the region from the northeast Pacific will bring better rain chances towards the end of the week and into the weekend, especially near the coast and across southwest Washington.
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.SHORT TERM...Now through Thursday Night...Clear skies, dry conditions and offshore winds will persist through the early evening. A pattern change is on deck for tonight through Wednesday morning as a weak frontal passage will bring cool, moist onshore flow back into the region. Normally, a frontal passage will bring the potential for precipitation, but with the dry air over the region and the overall weakness of the front am not expecting any precipitation to reach the coast. However, cool and moist conditions will persist and result in daytime highs Wednesday in the upper 60s to low 70s along the coast and upper 70s to low 80s inland. Thursday looks to be a few degrees cooler with daytime highs in the the upper 60s to low 70s along the coast and upper 70s to low 80s inland. low to mid 60s along the coast and mid to upper 70s inland. As the weekend approaches, a better opportunity for much cooler temperatures and precipitation presents itself. /42
.LONG TERM...Friday through Monday...By Friday, ensemble guidance converges on a generally dry pattern under a narrow, shortwave ridge that will warm the CWA up again by a few degrees. Expect daytime highs the upper 70s to low 80s inland and upper 60s to low 70s along the coast. A larger-scale trough begins to dig southeastward from the Gulf of Alaska on Saturday and will bring an increasing potential for precipitation. As the aforementioned low moves eastward, it will drag a cold front across the region resulting in precipitation chances climbing across the forecast area through Saturday. NW Oregon will see PoPs increase to 20-40% with higher probabilities 50-70% for southwest Washington and near Astoria. Sunday and into Monday, temperatures will be in the 70s inland and low to mid 60s along the coast. /42~Hall
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.AVIATION...High pressure and low-level offshore flow will maintain clear skies across the region throughout the TAF period, except at the coast where LIFR/IFR cigs will most likely develop late tonight (80% chance at KONP and a 50-60% chance at KAST).
In addition, gusty east winds will continue today before gradually decreasing in strength this evening into tonight. Until then, expect wind gusts up to 25-30 kt at KTTD, 20 kt at KHIO and 20-25 kt at KPDX. Winds are generally light and variable from KSLE to KEUG. Note the strong east winds are also resulting in a plume of ash and dust blowing westward off Mt. St. Helens, however this is not expected to impact any of the terminals.
KPDX AND APPROACHES...Clear skies will continue throughout the TAF period. Gusty east winds up to 20-25 kt will continue today before gradually weakening this evening into tonight. -TK
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.MARINE...Southerly winds are expected tonight ahead of an incoming Pacific front that will decay over the coastal waters, resulting in minimal impacts. Winds become northerly on Wednesday while strengthening. Gusts up to 25 kt are very likely to occur (90% chance) late Wednesday through Thursday, with gusts up to 30 kt possible (50-70% chance). Seas will also build to around 10 ft during that time. Therefore, have issued a Small Craft Advisory for all marine zones for a combination of winds and seas, including the Columbia River Bar. -TK
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.PQR WATCHES/WARNINGS/ADVISORIES...
OR...None. WA...None. PZ...Small Craft Advisory from 3 PM Wednesday to 5 AM PDT Thursday for PZZ210.
Small Craft Advisory from 3 PM Wednesday to 5 PM PDT Thursday for PZZ251>253-271>273.
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NWS PQR Office Area Forecast Discussion