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 18Z Sun

Westerly flow aloft as high pressure weakens over the region. Currently widespread VFR across the airspace as of 21Z Sat. Inland terminals will stay VFR through the period, while coastal terminals will see a return of deteriorated conditions by 04-06Z Sun. Probabilistic guidance suggests chances around 50-80% for MVFR CIGs, 40-60% for IFR CIGs, and 20-30% for LIFR CIGs from 04Z to 18Z Sun.

Otherwise, northwesterly winds around 6-12 kt will continue this afternoon, then weaken after 06Z Sun. KONP and a few inland terminals may see gusts up to 20 kt during the aforementioned time. Expect similar wind conditions tomorrow.

KPDX AND APPROACHES...VFR conditions through period. Northwest winds around 5-10 kt with gusts up to 20 kt possible during the afternoon/evening. Winds will then decrease around 06Z Sun. ~12

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.