textproduct: Portland

SYNOPSIS

A warming and drying trend is underway across southwest Washington and northwest Oregon as high pressure gradually builds inland. Temperatures will climb through the weekend and into early next week, with inland highs reaching the upper 80s to low 90s by Monday and Tuesday. Dry weather is expected to persist through at least the middle of next week.

LONG TERM...Monday through Wednesday

Ensemble guidance remains in strong agreement that the ridge will reach its greatest amplitude early next week, supporting the warmest temperatures of the forecast period. While NBM temperature spread has narrowed a degree or two over the past several forecast cycles, confidence that many inland locations will experience highs around 90 degrees Monday through Wednesday has shifted later. While confidence for reaching 90 degrees on Monday has decreased, the potential for 90 degrees remains for Monday through Wednesday. As a result of these changes, there is now higher confidence that Tuesday and Wednesday will be the days of peak heat next week.

Current probabilistic guidance indicates a 30-50% chance of reaching 90 degrees across much of the interior lowlands on Monday afternoon, then a 45-65% chance on Tuesday and Wednesday afternoon. Additionally, there is a 15-30% chance of temperatures reaching 95 degrees on Tuesday and Wednesday, highest across the traditionally warmer valleys. While these temperatures are typical for mid to late July, several consecutive warm afternoons combined with limited overnight cooling will result in pockets of Moderate HeatRisk, particularly for those without adequate cooling or prolonged outdoor exposure.

Little change in the overall pattern is expected through midweek as the ridge remains the dominant weather feature. As a result, dry conditions are forecast to continue with no meaningful precipitation expected across southwest Washington and northwest Oregon. ~12

AVIATION

Southwesterly flow aloft continues today as a low pressure system drifts northward towards British Columbia. As of 11Z Fri, mostly VFR conditions with a few terminals under high- end MVFR CIGs. Expect the marine stratus within the airspace this morning to remain high-end MVFR to low-end VFR until 18-20Z Fri, then trend clear and widespread VFR. Inland terminals will remain VFR through the rest of the TAF period. As for coastal terminals, expect a return to MVFR CIGS by 03-06Z Sat as marine stratus pushes back into the airspace. Current guidance suggests a 30-40% chance of MVFR and 10-20% chance of IFR CIGs at coastal terminals after 03Z Sat. Otherwise, expect north to northwesterly winds around 5-10 kt at all terminals through the period.

Lastly, smoke aloft is moving north into NW OR and SW WA from a wildfire in southwest OR burning to the north of KMFR. This may produce a broken smoke layer around 15-25 kft at times, especially over the Cascades.

KPDX AND APPROACHES...Expect VFR conditions through the period, with a 20-30% chance of MVFR CIGs from now until 17Z Fri. Expect VFR conditions and clear skies thereafter. Northwesterly winds around 3-8 kt expected through the TAF period. ~12

MARINE

Benign conditions for winds and seas with a typical summertime pattern expected today and early Saturday. Northerly winds around 10-15 kt are expected each afternoon/evening with gusts up to approximately 20 kt. Saturday afternoon through Sunday, northerly wind gusts will increase up to 25 kt for the waters south of Cape Falcon. Seas around 4 to 6 ft at 8 seconds will continue through Saturday afternoon, then become steeper and increase slightly to 6 to 9 ft on Sunday, bringing hazardous conditions for small craft.

A Small Craft Advisory remains in effect for the Columbia River Bar for a strong ebb current and choppy seas this morning from 4 AM to 10 AM. Additionally, a Small Craft has been issued for the waters south of Cape Foulweather OR late Saturday morning through early Sunday morning. ~12/23

PQR WATCHES/WARNINGS/ADVISORIES

OR...None. WA...None. PZ...Small Craft Advisory until 10 AM PDT this morning for PZZ210.

Small Craft Advisory from 11 AM Saturday to 5 AM PDT Sunday for PZZ253.

Small Craft Advisory from 5 PM Saturday to 5 AM PDT Sunday for PZZ273.