textproduct: Seattle/Tacoma

SYNOPSIS

Building marine stratus is present on satellite imagery early this morning with weak high pressure generally settling over the region. Flow aloft is zonal, with a low pressure system moving into northern California. The next system will arrive on Tuesday for lowland rain and mountain snow. More active conditions set up through the end of the week.

SHORT TERM /TODAY THROUGH WEDNESDAY/

Zonal flow aloft and building marine stratus along the coast will persist through the day today. Expect fog in areas from Olympia west to the coast and down through the Chehalis Valley this morning. More isolated for is possible in western Snohomish county. Once the fog dissipates this afternoon, the high pressure will skirt east, allowing the next system to move in on Tuesday into Wednesday.

The system arriving on Tuesday will bring about lowland rain and mountain snow, but generally for elevations above 5000ft. Breezy winds will materialize as the front moves through on Tuesday evening, with the windiest locations being along the north coast, and throughout Puget Sound. Snow levels will lower on Wednesday to about pass level in the Cascades but total amounts at this point seem to be well below criteria. Storm total snow from Tuesday through Thursday morning could yield another 5-7 inches for Stevens Pass and 1-4 across Snoqualmie Pass.

LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/

The active weather pattern persists into the later half of the week with additional systems arriving through Friday. More rain and mountain snow are in the forecast. Right now, the mountainous area that is likely to receive the most snow is the Mount Baker area, with limited amounts across the rest of the Cascade passes due to higher snow levels forecast at this time. Expect periods of rain and cooler conditions through the weekend.

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AVIATION

VFR with areas of IFR/LIFR in fog slowly expanding across western Washington early this morning. Conditions are favored to remain VFR east of the Puget Sound, with terminals elsewhere seeing potential for fog development this morning. Conditions will improve by the late morning with all terminals returning to VFR by the afternoon. Light southerly winds will persist through much of the TAF period, beginning to increase early Tuesday as the next system approaches.

KSEA...VFR early this morning with light NE winds slowly shifting southerly throughout the morning hours. Conditions are favored to remain VFR through the TAF period, with a slight chance (10% to 20% probability) of fog drifting over the terminal bringing brief MVFR/IFR conditions.

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MARINE

High pressure stationed offshore will weaken today, allowing easterly winds over area waters to turn southerly by this afternoon. Seas will hold at around 3 to 4 feet today. Areas of fog may reduce visibilities at times across the coastal waters today as high pressure persists.

The next frontal system will cross area waters Tuesday, bringing the next chance for Small Craft winds across the coastal waters, Strait of Juan de Fuca, and inner waters. Seas over the coastal waters will build to around 7 feet and steepen in conjunction with the stronger winds, becoming quite choppy.

Additional systems will cross the region through the middle of the week, maintaining chances for additional Small Craft Advisory winds through the Strait of Juan de Fuca, particularly on Wednesday and also into the weekend. Seas will build to around 8 to 11 feet late Wednesday into Thursday before easing to 7 to 8 feet on Friday. Seas are expected to build back to 9 to 11 feet by the weekend.

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HYDROLOGY

No river flooding is expected over the next 7 days.

SEW WATCHES/WARNINGS/ADVISORIES

WA...None. PZ...None.