textproduct: Portland

SYNOPSIS

Warm and dry conditions continue today, but temperatures are expected to gradually moderate toward August norms by Sunday, continuing into early next week. Renewed onshore flow will keep smoke east of the Cascades, while precipitation chances remain very low through at least the middle of next week. Temperatures are likely to trend warmer again late next week.

DISCUSSION...Today through Friday

Broad high pressure over the region today will maintain warm and dry conditions with highs reaching the mid to upper 80s inland. A weak shortwave trough will bring a few high clouds across the area this morning while marine stratus likely remains at the coast, with afternoon sun expected. Another round of onshore flow will bring breezy northwest winds later this afternoon and evening.

While winds from the west/northwest generally remain around 15 mph or weaker across most areas, the breeziest locations will be along the Central Columbia River Gorge and portions of the Upper Hood River Valley where gap winds are forecast to gust up to 30-35 mph, with a 20-30% chance for gusts exceeding 40 mph. Combined with low relative humidity and dry fuels, these conditions would be favorable for rapid fire spread. NWS Pendleton has issued a Red Flag Warning for the Central Gorge and portions of Eastern Hood River County, in effect through 11 PM Saturday. Elsewhere across northwest Oregon and southwest Washington, higher relative humidity and weaker winds will not be favorable for rapid fire spread.

There is high confidence temperatures trend a few degrees cooler into the low to mid 80s Sunday through early next week as a more zonal flow pattern emerges. Majority of ensemble members show a weak trough approaching the Pacific Northwest middle of next week, however, it appears to be a dry trough with no precipitation chances expected. Ensemble clusters indicate increasing probabilities for a steeper ridge developing offshore late next week, which would allow for temperatures to warm again into the upper 80s to lower 90s potentially. DH/10

AVIATION...Through 12Z Sun

Southwest flow aloft becomes westerly today as high pressure weakens over the region. Marine stratus continues to develop along portions of the coast this morning with MVFR to LIFR CIGs. Guidance indicates stratus is likely to scatter out by 17-19z Saturday, with widespread VFR conditions expected through 06z Sunday. Inland terminals may see a few high clouds across the area today with VFR conditions persisting through the period. A stronger marine push this morning could allow stratus to push east through the Columbia River to around KKLS. Northwesterly winds increase again to 6-12 kt this afternoon. KONP may see gusts up to 20 kt after 18Z Sat as winds over the waters strengthen, decreasing by 04-06z Sun.

KPDX AND APPROACHES...VFR conditions through period. Mid to high level clouds likely after 12z Sat. Light northwest winds increase to around 9-12 kt after 21z Sat. /DH

MARINE

High pressure offshore will maintain northerly winds through the weekend and into next week. Winds will remain 20 kt or less through this morning. Surface pressure gradients will then tighten this afternoon, bringing increased chances for wind gusts up to 25 kt south of Cape Foulweather through the weekend and into early next week. Specifically, there is a 40% chance for small craft wind gusts today south of Cape Foulweather, then increased chances of 50-70% on Sunday. Wind driven seas are expected to remain around 4 to 6 ft through the next week. /DH

PQR WATCHES/WARNINGS/ADVISORIES

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