textproduct: Seattle/Tacoma

SYNOPSIS

An upper level low will continue to spin multiple fronts through early week. These fronts will bring several rounds of lowland rain, mountain snow and gusty winds. Active weather continues through midweek, with a potential drying trend by the end of the week.

SHORT TERM /TODAY THROUGH TUESDAY/

A surface low continues to remain offshore this morning with multiple fronts crossing over western Washington this morning. Widespread rain showers will continue over the lowlands with mountain snow continuing as well as snow levels sit in the 3000 to 4000 foot range. Breezy winds along the coast, the Cascade foothills, and Whidbey Island will start to slowly taper off later this morning into the afternoon. A Winter Weather Advisory remains in effect for the Cascades of northern King County including Stevens Pass, along with the Cascades of Whatcom County which includes Mt. Baker. Expected accumulations around 5 to 10 inches through Monday morning. As snow levels range from 3000 to 4000 feet, can't rule out some light accumulations also at Snoqualmie Pass during this time. Lowland rain and mountain snow will continue throughout Monday with temperatures in the upper 40s and lower 50s.

Rain coverage will decrease on Tuesday, with some lingering showers around the area, more notably in the southern half of the area.

LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/

Weak disturbances will push through the region throughout the rest of the week, with some light shower activity expected each day. Ensemble guidance has trended drier than the previous days, with temperatures staying around average, in the upper 40s and lower 40s. Uncertainty continues to exist in the pattern into the weekend, but we may be shifting into drier weather.

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AVIATION

Southerly flow aloft will become more southwesterly today as a broad upper trough remains situated offshore. Easterly flow continues near the surface early this morning and will weaken by midday. Latest radar shows the next round of rain making its way inland across the Olympic Peninsula this morning, though conditions at the area terminals remain primarily VFR. Expect precipitation coverage to increase across the area throughout the morning as a frontal system moves onshore. Conditions may briefly drop down to MVFR in heavier shower activity, though will most likely remain VFR through much of the day. Conditions then look to gradually lower to MVFR across the region later tonight. Surface winds will shift to the south/southeast and could be gusty in vicinity of the front, with the strongest winds expected for terminals along the Pacific Coast and across the North Interior.

KSEA...VFR conditions early this morning. Periods of rain will continue throughout the day, with increasing precipitation coverage expected at the terminal between 13-15Z. Conditions may briefly drop to MVFR in any heavier shower activity, though look to remain mostly VFR through much of the day before dropping to MVFR late tonight. Easterly surface winds persisting between 8-14 kt this morning will become more S/SE by late morning. Gusts to 20-25 kt will be possible at times.

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MARINE

Low pressure systems rotating around the northeastern Pacific will push a strong frontal system through the area waters today. This will continue to bring gales to the coastal waters and the Strait of Juan de Fuca and small craft southerlies to the remainder of the interior waters today. Seas have been building across the coastal waters early this morning in response to the strong winds, with latest buoy observations showing seas hovering between 12-18 ft. The dominant wave group will be out of the south, with the outer coastal waters likely approaching 20-25 ft later this morning. Winds will then ease by this evening.

A weaker frontal system will then move across the area waters on Monday and will be followed by high pressure building back over the coastal waters in its wake. The high pressure system will then remain situated over the coastal waters into the second half of the week. Seas will gradually subside towards 6-8 ft through the day on Monday and further subside towards 5-7 ft by Tuesday.

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HYDROLOGY

The threat for flooding on the Skokomish remains but the timing has shifted dramatically. Due to periods of sustained rainfall (moderate at times) Skokomish river is approaching minor flooding on Monday but briefly. With the thin mountain snowpack and existence of low elevation snow, rain on snow could produce enough snow melt getting added to the otherwise unimpressive forecast precipitation amounts to result in flooding. Widespread flooding is not expected due to lower snow levels but rises on other area rivers is expected.

SEW WATCHES/WARNINGS/ADVISORIES

WA...Wind Advisory from 7 AM this morning to 3 PM PST this afternoon for San Juan County.

Winter Weather Advisory from 10 PM this evening to 10 AM PST Monday for Cascades of Snohomish and Northern King Counties-Cascades of Whatcom and Skagit Counties.

Wind Advisory until 10 AM PST this morning for Foothills and Valleys of Central King County-Foothills and Valleys of Pierce and Southern King Counties-Foothills and Valleys of Snohomish and Northern King Counties-Grays Harbor County Coast-Northern Washington Coast.

PZ...Small Craft Advisory until 10 PM PST this evening for Grays Harbor Bar.

Gale Warning until 4 PM PST this afternoon 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-East Entrance U.S. Waters Strait Of Juan De Fuca-West Entrance U.S. Waters Strait Of Juan De Fuca.

Small Craft Advisory from 4 PM this afternoon to 4 AM PST Monday for East Entrance U.S. Waters Strait Of Juan De Fuca.

Small Craft Advisory from 4 AM early this morning to 4 AM PST Monday for Admiralty Inlet-Northern Inland Waters Including The San Juan Islands.

Small Craft Advisory from 4 AM early this morning to 10 PM PST this evening for Puget Sound and Hood Canal.

Small Craft Advisory from 4 PM this afternoon to 4 PM PST Monday for 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.