textproduct: Portland

SYNOPSIS

Showery conditions expected to persist through Thursday afternoon. Heavy snow is expected in the Cascades with another 6 to 12 inches possible around pass levels. There is a 20-40% chance snow mixes in with rain overnight in the Willamette Valley. No accumulations or travel issues are expected given the warm ground conditions and lows in the mid 30s. Drying trend to end the week with potential for more mild temperatures early next week.

LONG TERM...Thursday Night through Wednesday

Dry weather returns on Friday as ensemble guidance is in agreement of an upper level ridge building over the Pacific Northwest. By the weekend, the majority of ensemble members are showing some light rain along the coast and southwest Washington as a weak shortwave moves in though will be non-impactful. Ensembles have come into better agreement with high pressure ridging. 500 mb heights shows good agreement within the ensembles regarding the consistency of the ridge. Ensembles are showing better agreement in the ridge building over the region early next week and supporting dry and mild conditions into the middle of the week. Could see a warm up into the upper 50s to low 60s by Tuesday areas west of the Cascades. -19/10

AVIATION

Moist, northwesterly flow aloft continues as an upper level trough moves across the region. Post frontal showers continue through Thursday. Expect a mix of MVFR and low-end VFR as multiple rounds of showers move through the area. There is a 15-25% chance for thunderstorms through 09z Thu along and west of the Coast Range south of Tillamook. Any heavy shower or thunderstorm may bring lightning, heavy rain, erratic outflow wind gusts, and/or small hail. Southwesterly winds persist for inland terminals, mainly less than 10 kts, except for westerly winds along the coast with gusts 20- 25 kt possible through 12z Thu. High pressure begins building over the region later Thursday with showers tapering off after 00-06z Fri.

KPDX AND APPROACHES...Showers continue through Thursday. Conditions a mix of MVFR and VFR, trending more VFR after around 09z Thu. Southwest winds around 5-10 kt through the TAF period. Chances for MVFR CIGs increase again after 16z Thu to around 50-60%. -DH/03

MARINE

As of 10 PM PST Wednesday, onshore westerly winds expected to continue through Thursday night, though as high pressure off the northern California coast begins building north overnight, winds will begin to decrease. Current buoy observations indicate winds remain breezy with gusts up to 30 kt, but over the next few hours, winds will decrease quickly to gusts around 20-25 kts by 5 AM PST Thursday. Winds are expected to remain here through most of Thursday, decreasing in the afternoon to gusts below 20 kts.

Seas at buoys 89, 29, and 50 were observed around 18-19 ft around 16 seconds as of 9 PM PST. Guidance remains consistent that significant wave heights are likely to continue rising over the next few hours, peaking around 20 to 24 ft tonight, with a period of around 16 seconds. Seas will likely subside slowly, eventually falling into the mid- teens by Thursday evening. The Hazardous Seas Warning remains in effect through 10 PM Thursday. Seas are not expected to fall below 10 ft until Friday afternoon. High pressure settles over the area on Friday while south to southeasterly winds develop across the waters. -DH/03

BEACH HAZARDS

High surf conditions are expected through Thursday afternoon as a long-period northwesterly swell arrives, bringing breakers up to 25 to 27 ft within the surf zone. A High Surf Advisory has been issued to cover this threat. Destructive waves may wash over beaches, jetties, and other structures unexpectedly. People can be swept off rocks and jetties and drown while observing high surf. Minor beach erosion may damage coastal properties and buildings. Higher than normal water run-up is expected on beaches and low-lying shoreline.

Although high surf conditions ease Thursday night into Friday, a high threat of sneaker waves will remain a threat for several days thereafter. Waves may run further up the beach than normal. These waves can easily catch people off guard. Never turn your back to the ocean. Razor clammers should use extra caution. -10/23

PQR WATCHES/WARNINGS/ADVISORIES

OR...High Surf Advisory until 4 PM PST Thursday for ORZ101>103.

Winter Storm Warning until 4 PM PST Thursday for ORZ126>128.

WA...High Surf Advisory until 4 PM PST Thursday for WAZ201.

Winter Storm Warning until 4 PM PST Thursday for WAZ211.

PZ...Hazardous Seas Warning until 4 PM PST Thursday for PZZ210.

Hazardous Seas Warning until 10 PM PST Thursday for PZZ251>253- 271>273.