textproduct: Portland

SYNOPSIS

Cool onshore flow and persistent cloud cover will maintain below average temperatures over the area through Thursday with little change in the overall weather pattern. Conditions will be mainly dry aside from a few stray sprinkles, mainly over higher terrain. A gradual warming trend develops Friday into the holiday weekend with inland valleys likely warming above 80 degrees by the 4th of July (70-90% chance).

DISCUSSION...Monday afternoon through Sunday night

Visible satellite imagery Monday afternoon shows mostly cloudy skies across NW OR and SW WA. Temperature observations at 2 PM are only in the low to mid 60s across the interior lowlands and 50s to low 60s elsewhere under the cloud cover. This is due to longwave situated over the Western US bringing cooler and moist air from the north into the PacNW. Model ensemble guidance continues to suggest this pattern will continue through Thursday, allowing cool onshore flow to persist with extensive cloud cover each day during the morning and early to mid afternoon hours. This will keep temperatures cooler than average for this time of year with high temperatures ranging from the mid 60s to lower 70s each day, coolest at the coast. The latest forecast is trending mainly dry each day aside from a few stray sprinkles from time to time, mainly over higher terrain.

Conditions will begin trending warmer Friday into the upcoming holiday weekend as weak upper level ridging develops. Although there is still a large degree of total model spread for temperatures, confidence has increased highs will warm to at least 80 degrees for inland valleys by the 4th of July Saturday (70-90% chance per the latest NBM guidance). Probabilities for highs of 80 degrees or warmer are similar on July 5th as well. Chances for highs of 90 degrees or warmer are under 10% on Saturday, increasing Sunday to 10-25%. That being said, chances for highs at or above 95 degrees are only 0-5%, suggesting the warmest possible scenario would be somewhere in the lower 90s. In addition, overnight lows are expected to be in the 50s, which will offer excellent relief for those without access to air conditioning regardless of whether or not temperatures end up in the 80s or lower 90s. -23/03

AVIATION

Widespread cloud cover continues with the majority of the airspace fluctuating between VFR and MVFR conditions through the TAF period. Starting around 08Z Tuesday, coastal locations will have a 5-15% chance for IFR conditions to develop, with KONP having a higher chance. Inland locations will generally be VFR with CIGs between FL030 to FL050, with occasional periods of MVFR at any given time and location. Around 18Z-20Z Tuesday, conditions are expected to improve to predominately VFR conditions. Generally west/northwest winds less than 10 kt.

KPDX AND APPROACHES...Widespread cloud cover is resulting in VFR conditions between FL030 to FL050, with occasional periods of MVFR at any given time through the TAF period. Generally west/northwest winds less than 10 kt. /42

MARINE

Northwest winds around 10 to 20 kt with steep seas near 7 to 9 ft at 9 to 10 seconds driven mainly by a northwest swell continue today through early Wednesday. These northwest winds will increase significant wave heights towards 8 to 11 ft Tuesday morning. Seas will be highest over the outer waters, mainly north of Cape Falcon, with a 10-20% chance significant wave heights will peak slightly over 11 ft. Winds and seas will ease significantly Wednesday afternoon and evening, with benign conditions expected Thursday and Friday.

Given steep seas and wind gusts upwards of 20 kt, a Small Craft Advisory is in effect for both the inner and outer waters through Tuesday night. Rough bar conditions are also expected within the main channel of the Columbia River Bar late Monday morning through late Tuesday morning with steep seas around 7 to 10 ft at 9 seconds and northwest winds around 10 to 15 kt. There is also a Small Craft Advisory on Tuesday morning for a strong ebb current and seas near 10 ft at the Columbia River Bar. ~12/23

PQR WATCHES/WARNINGS/ADVISORIES

OR...None. WA...None. PZ...Small Craft Advisory until 11 AM PDT Tuesday for PZZ210.

Small Craft Advisory until 11 AM PDT Wednesday for PZZ251- 271>273.

Small Craft Advisory until 2 AM PDT Wednesday for PZZ252-253.