textproduct: Portland

SYNOPSIS

Warm and dry conditions continue through the upcoming week as temperatures gradually moderate towards August normals. 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 trend warmer towards the latter part of the upcoming week.

DISCUSSION...Tonight through Friday

Zonal flow aloft with west/northwest winds at the surface will help to support near to slightly warmer than normal daytime highs through the weekend and into at least the middle of next week. Towards Thursday, a majority of ensemble members are showing a weak trough dropping down out of British Columbia, which looks to bring relatively cooler temperatures into the region. However, said system looks to be dry with no precipitation expected. Looking towards the end of next week and into the following weekend, ensemble clusters indicate increasing probabilities for a steeper ridge developing offshore, which would allow for temperatures to warm again into the upper 80s to lower 90s potentially.

Through the forecast period expect winds from the west/northwest 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 approaching 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. It should be noted that 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. /42-DH

AVIATION...Through 06Z Mon

Satellite imagery as of late Saturday evening depicts marine stratus re-developing along the coast. High confidence for IFR/MVFR CIGs after 06-08z Sun for coastal terminals due to this stratus and lasting through 18-21z Sun. Between 21z Sun-03z Mon, there is about a 50-70% chance at any given hour for marine stratus to break out and briefly improve conditions along the coast to VFR. Low marine stratus returns Sunday evening. For Willamette Valley terminals, predominately VFR with clear skies through the TAF period. Northwesterly across all terminals, strongest in the afternoon with gusts up to 25 kt along the coast and up to 18-20 kt across the Valley.

KPDX AND APPROACHES...VFR through the TAF period with clear skies. 10-20% chance for stratus development in the far eastern Portland Metro at any given hour between 12-17z Sun. Northwesterly winds around 5 kt tonight, strengthening to 10-11 kt in the afternoon with gusts up to 19-20 kt. -10

MARINE

High pressure offshore will maintain northerly winds through the weekend and into next week. Surface pressure gradients have tightened 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 remains a 40% chance for small craft wind gusts today south of Cape Foulweather, then a 60-80% chance on Sunday. As a result, a Small Craft Advisory has been issued for the inner and outer waters south of Cape Foulweather from 12 PM Sunday to 2 AM Monday. Similar small craft conditions may reoccur Monday for the waters south of Cape Foulweather. Wind driven seas are expected to remain around 4 to 6 ft through the weekend and most of next week. ~12/DH

PQR WATCHES/WARNINGS/ADVISORIES

OR...None. WA...None. PZ...Small Craft Advisory from noon Sunday to 2 AM PDT Monday for PZZ253.

Small Craft Advisory from 3 PM Sunday to 2 AM PDT Monday for PZZ273.