textproduct: Seattle/Tacoma

SYNOPSIS

A frontal system will continue to bring widespread precipitation and breezy conditions to Western Washington today. Unsettled conditions are favored into next week. Light showers will linger early next week. Another system will arrive midweek, bringing widespread rain, mountain snow, and cooler temperatures to the region.

SHORT TERM /TODAY THROUGH TUESDAY/

Rain continues to move across Western Washington early this morning as a low pressure system moves southward offshore. Latest radar imagery shows pockets of moderate to heavy rainfall moving across the region. The bulk of the precipitation will fall over the coast and the Olympic Peninsula with 1.00-1.50 inches. Other locations will see amounts ranging 0.10-0.20 inches east of I-5 and 0.25-0.50 inches west of I-5. Southerly winds are expected to become breezy along the coast, San Juan Islands, and the Olympic Peninsula this morning and ease late tonight. Latest high-res guidance suggests wind gusts up to 35 mph. High temperatures in the low to mid 50s today.

Models have come to a better agreement on the projected path of the low. The center of the low will remain offshore today and move inland Monday morning near the Oregon/Washington border. This will result in light showers lingering into Monday. A weak shortwave will slide down from British Columbia on Tuesday for another chance of light precipitation.

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LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/

There is good agreement among models that a low pressure system will slide down from the British Columbia coast late Tuesday towards Western Washington, bringing another round of widespread precipitation through at least Thursday. Additionally, a colder air mass will accompany this system. Latest guidance suggests high temperatures will only peak into the upper 40s to low 50s and overnight temperatures will dip into the 30s, with upper 20s possible in the valleys by Thursday. Snow levels will also decrease below 3500 ft with this system, bringing light snow accumulations to the passes. Latest guidance suggests the passes may receive around 4 inches of snow, while the higher mountain peaks may see around 7 inches. Models start to struggle Saturday on the upper-level pattern. Some members have a weak ridge building behind the low pressure system, however the majority of members at this time favor an upper-level trough to remain over Western Washington.

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AVIATION

Southwest flow aloft will become southerly later today then southeasterly overnight as an upper low offshore moves onshore over northwest Oregon. Ceilings will be a mixed bag across the region today as bands of precipitation associated with the system offshore spread into the region. MVFR ceilings will be mostly confined to the coastal areas with primarily VFR for interior terminals. Ceilings may briefly drop to MVFR thresholds for interior areas mainly south of KSEA this morning.

KSEA...Mainly lower end VFR expected today with periods of light rain moving through the area into this afternoon. Precipitation should begin to decrease toward this evening. Surface winds E/NE 4 to 7 knots.

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MARINE

A gradually weakening surface low will shift southward over the offshore waters today before moving onshore over the northern Oregon coast on Monday morning. Small craft advisories remain in effect for a combination of wind and seas over the coastal waters into this evening. Small craft advisories also remain in effect for easterlies in the strait. Winds and seas will be ease and subside tonight as the low offshore further weakens and moves ashore over Oregon. Another front will reach the waters on Wednesday.

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SEW WATCHES/WARNINGS/ADVISORIES

WA...None. PZ...Small Craft Advisory until 5 PM PDT this afternoon for Grays Harbor Bar.

Small Craft Advisory until 11 PM PDT this evening for Central U.S. Waters Strait Of Juan De Fuca-Coastal Waters From Cape Flattery To James Island 10 To 60 Nm-Coastal Waters From Cape Flattery To James Island Out 10 Nm-Coastal Waters From James Island To Point Grenville 10 To 60 Nm- Coastal Waters From James Island To Point Grenville Out 10 Nm-Coastal Waters From Point Grenville To Cape Shoalwater 10 To 60 Nm-Coastal Waters From Point Grenville To Cape Shoalwater Out 10 Nm-West Entrance U.S. Waters Strait Of Juan De Fuca.

Gale Warning until 5 PM PDT this afternoon for East Entrance U.S. Waters Strait Of Juan De Fuca.

Small Craft Advisory until 5 PM PDT this afternoon for Northern Inland Waters Including The San Juan Islands.