textproduct: Portland

SYNOPSIS

A bit more of a dynamic weather pattern over the next several days as high pressure gives way to a longwave trough over the area. Rain chances increase for Wednesday night into Thursday with a slight chance (10-20%) for thunderstorms into Thursday morning. Rain accumulation will generally be orographically driven. Drying occurs starting Friday through the weekend as temperatures heat up once again. Moderate HeatRisk forecast for urban areas on Sunday and Monday.

LONG TERM...Friday through Tuesday

Conditions will begin to settle on Friday, though expect temperatures to remain seasonable or just slightly above normal. Once challenge on Friday is what ends up happening with the low aloft. Some models suggest that the low will stay more northerly, while others want to keep it further south. The overall Grand Ensemble shows the low center tracking p and over Vancouver Island on Friday which will allow for drier and warmer air to move in. This will set the stage for the weekend as conditions become increasingly hotter and drier. In this pattern, marine stratus is likely, especially along the coast though it could transition down the Columbia River into the interior lowlands. If cloud cover becomes pervasive, it will have an impact on high temperatures and minimum humidity.

As we move into the weekend, high pressure builds once again which will cause temperatures to rise. This ridge amplifies through Monday which will bring even warmer temperatures. Looking at Moderate HeatRisk for urban areas around the greater Portland-Vancouver metro area, the Columbia River Gorge, and the Upper Hood River Valley on both Sunday and Monday. There is around a 10% chance of highs hitting 100 degrees or more on both Monday and Tuesday and that is mainly within the inland valleys. Note that one trend that has been observed is that the highest temperature forecasts have been pushed off one day at a time as models come in. Therefore, the exact dates may be a bit more up in the air as we near - especially as the ridge remains anchored in place.-27

AVIATION

VFR conditions under mostly clear skies expected to continue for all inland locations through the remainder of the TAF period. Coastal locations will maintain VFR until around 03Z-05Z Wednesday. Afterwards, expect IFR/LIFR conditions to manifest as shallow, marine stratus develops. There is a 45-65% chance for IFR conditions and a 25-45% chance for LIFR conditions. These lowered flight conditions along the coast, are expected to persist through around 15Z-17Z Wednesday with conditions expected to improve towards VFR around that time.

North/northwest winds to 5-10 kt inland and 7-12 kt at the coast around 18Z-20Z Tuesday. Coastal terminals may see gusts up to 20 kt. Light northerly winds return around 03Z-06Z Wednesday across the airspace.

KPDX AND APPROACHES...VFR under mostly clear skies. North/northwesterly winds around 5-8 kt, expected to become light and northerly around 03Z Wednesday. -42

MARINE

Benign conditions with a typical summertime pattern expected to persist through the week. Northerly winds 10-15 kt expected with intermittent afternoon gusts up to 20 kt each day. Seas 4-6 feet at 8-10 seconds.

A Small Craft Advisory is in effect from 3AM to 9AM Wednesday morning for the Columbia River Bar for rough seas due to a very strong ebb current leading to seas of 6 to 7 ft. -42

PQR WATCHES/WARNINGS/ADVISORIES

OR...None. WA...None. PZ...Small Craft Advisory from 3 AM to 9 AM PDT Wednesday for PZZ210.