SHORT TERM
Now through Saturday night...Scattered showers will continue across NW Oregon and SW Washington through this evening as an upper level trough moves overhead.
Additional precipitation amounts through tomorrow (Thursday)
afternoon are forecast near or below 0.10 inch west of the Cascades, while the Cascades could see an additional 0.25 to 0.50 inch. Will note that there also remains a 20-30% of thunderstorms across the region through this evening as the atmosphere remains unstable from cooler air aloft. If clouds clear out late this afternoon, additional surface heating could enhance convection. Any passing thunderstorms will be accompanied with locally heavy rain, minimizing concerns for any new fire starts due to lightning.

Showers and thunderstorms diminish tonight as the trough shifts east of the Cascades, though northwest flow in the wake of the trough will keep chances for a few showers over the area into Thursday afternoon. Expect these showers to mostly favor the higher terrain due to orographic enhancement, but model QPF amounts are still limited to around 0.10 inch across most of the area. Expect a general clearing trend from west to east through the afternoon with highs inching back upwards into the low 70s for interior valleys. Temperatures will continue to gradually increase into the low to mid 70s on Friday as shortwave ridging moves overhead and brings an end to any lingering shower activity. -Alviz/CB

LONG TERM
Saturday through Tuesday...Medium range guidance has slightly sped up the arrival of the next trough into the region on Saturday, which will bring about another period of showery conditions and cooler temperatures this weekend into the early next week. The majority of ensemble members (80%) from WPC cluster analysis show the trough increasing in amplitude and dipping southward toward California. These members suggest below average 500 mb heights, likely keeping temperatures slightly below seasonal norms. However, with the trough extending further south, this could lead to lower shower coverage and precipitation amounts in our area. Forecast amounts look light, as 24 hr probabilities for 0.50 inch of rain or greater this weekend into early next week are around 15-30%.
-Alviz

AVIATION
An upper level trough dropping into Oregon today will shift east of the Cascades overnight bringing increasing northwesterly flow aloft along with scattered showers across the airspace. This resulting in generally VFR conditions with localized and temporary MVFR/IFR (15-30% probability across the airspace)
through at least 18Z Thursday, as showers slowly dissipate through the overnight hours. KONP will have a 30% probability of IFR/LIFR conditions developing around 12Z-14Z Thursday. Conditions expected to improve to widespread VFR for most areas by 20Z Thursday. The exception to this will be KAST as they will likely return to MVFR/IFR around 03Z Friday.

PDX APPROACHES...Generally VFR conditions with localized and temporary MVFR/IFR (15-30% probability) that will be associated with passing showers. Showers will slowly dissipate through out the overnight hours with conditions becoming predominately VFR around 18Z-20Z Thursday. /42

MARINE
Weak low pressure off the north Oregon coast will dissipate tonight as high pressure builds offshore. Westerly winds this afternoon shift to the northwest tonight, increasing to around 10-15 kt. Northerly winds continue across the coastal waters through Friday before a weak front approaches the northern waters late Friday and into the weekend. Given the relatively weak winds across the waters over the next week, expect seas to generally hover between 4 to 7 ft through early next week. /DH

PQR WATCHES/WARNINGS/ADVISORIES

OR...None.
WA...None.
PZ...None.