SHORT TERM
Tonight through Sunday Night...Models and their ensembles are in good agreement that broad weak upper level troughing will linger over the Pacific Northwest for the remainder of the weekend. This will maintain periods of low clouds along the coast and lower Columbia River each morning before clouds retreat to near the coast in the afternoon. 850mb temperatures near 12-15C will keep inland temperatures in check with daytime high temperatures topping out in the low to mid 80s. LRAPA has issued an Air Quality Advisory through Saturday afternoon for eastern Lane County due to smoke pooling in the Cascade valleys. Breezy conditions will continue through the central Columbia River Gorge Saturday and Sunday afternoons and evenings with winds gusting up to 25-35 mph near Hood River.


LONG TERM
Monday through Friday...Models and their ensembles are in good agreement a shortwave trough will linger across the Pacific Northwest into early next week as another shortwave trough currently over the Gulf of Alaska drops southeastward into the Pacific Northwest over the next 48 hours and reinforces the existing shortwave trough. However, there still remain fairly significant differences in the amplitude of the shortwave trough that sets up over the Pacific Northwest. This results in a considerable amount of uncertainty in far south a front will push into the area and how much, if any, rain will fall across good portions of the forecast area. For example, the latest NBM suggests there is 65% chance that a tenth of an inch of rain falls in Astoria between Monday and Tuesday.
Those odds decrease as one moves south and east across our forecast area to 50% in Portland and a 30% chance for Eugene.

Unfortunately, for our wildfires burning in the Cascades, the odds of soaking 0.50" of rain is 30-40% across our north Oregon Cascades and is as low as 10% for our southern Lane County Cascades. The more concerning item is that the ensemble guidance is in strong agreement 500mb heights will climb above climatology, which will result in a warming trend during the middle to latter half of next week. The odds that temperatures climb back into the 90s for the Willamette Valley and Columbia River Gorge climbs back to at least 70-90% (highest odds south and east) by next Thursday and Friday.




AVIATION
Intermittent MVFR at the coast through the rest of Saturday night, with marine stratus occasionally drifting over terminals. Central/southern coastal terminals will likely clear to VFR by 20z Sat, but northern coast (KAST) sees 80% chance of MVFR or lower conditions remaining throughout the TAF period. Inland, VFR conditions expected through Saturday evening, though a VFR overcast deck may occur between now and 14-18z Sat at the north Willamette Valley. Only around a 20-30% chance of brief MVFR cigs near the northern Valley (KPDX, KTTD) between 12-20z Sat.
Northwest winds around 10 kt for most terminals, with gusts up to 20 kt possible Saturday afternoon and evening.

It should be noted that wildfires burning in the Central OR Cascades (east of KEUG) as well as within the Columbia River Gorge (east of KPDX and KTTD) could result in some slant range visibility issues at times as smoke/haze spreads east of the Cascades. However, predominately west to east flow should mitigate these impacts.

PDX AND APPROACHES...VFR conditions and clear skies throughout most of the period. 20-30% chance of MVFR cigs between 14-18z Saturday due to marine stratus building in from the coast, but this would be patchy and temporary if it does occur. NW sustained winds up to 12 kt possible Saturday afternoon and evening.




MARINE
A weak upper level trough will slowly meander eastward through the weekend. Small Craft Advisory has ended for all waters, and winds look to remain closer to 15 kt throughout the rest of the weekend and early next week. Seas will remain around 4 to 6 ft. Overall benign conditions through the weekend with a southerly wind shift expected late Sunday/early Monday.
-JH/JLiu




PQR WATCHES/WARNINGS/ADVISORIES

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