textproduct: Seattle/Tacoma

SYNOPSIS

Dry conditions through today as the upper ridge axis slides to the east. A frontal system moves through on Saturday for the return of lowland rain, breezy winds, and cooler conditions. A more active pattern at times expected into next week with cooler temperatures.

SHORT TERM /TODAY THROUGH SUNDAY/

Clear skies across much of Western Washington this morning, with some areas of fog from Whidbey Island northwards as well. Otherwise, mostly sunny conditions with a mix of high clouds at times today. Temperatures will reach the mid to upper 50s with mid 60s near the Cascade Valleys.

The upper ridge axis overhead continues to shift east on Saturday ahead of a frontal system that will move across the region. Lowland rain returns on Saturday, with snow levels ranging 5000 to 6000 feet with this front. In addition, locally breezy winds are expected, mainly along the coast, and from Whidbey Island northwards. HREF/REFS probabilities suggest south wind gusts ranging from 25 to 35 MPH gusts in these areas Saturday morning. Another system will then track into northern Oregon and southern Washington into Sunday, which may bring another round of rainfall for southern portions of Western Washington. Otherwise, snow levels do begin to lower by later Sunday, reaching 3500 to 4000 feet by Sunday night.

LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/

Weak troughing aloft will promote continued unsettled weather on Monday, however, precipitation amounts are forecast to be rather light on Monday for most areas. Western Washington returns to a bit more of a split flow pattern Tuesday and Wednesday, with the bulk of the energy from the trough over California. This lends to a more of a drier forecast late Tuesday into midweek, with temperatures a bit cooler in the upper 40s to low 50s. Ensembles suggest another frontal system may approach the area by Thursday with more SW flow aloft, although some uncertainty remains, and have kept with NBM POPs mainly peaking 40 to 50% on Thursday.

AVIATION

Southwest flow aloft will increase tonight as a frontal system approaches. VFR conditions will prevail into this afternoon with high and mid level moisture increasing from late this afternoon into tonight. Ceilings will lower to MVFR in rain along the coast around 12Z with said conditions spreading to interior areas 15Z-18Z Saturday morning. Gusty southeasterly surface winds will develop ahead of the front early Saturday along the coast and interior areas from around KPAE northward.

KSEA...VFR with increasing high and mid clouds late today. Ceilings will gradually lower overnight and are expected to become MVFR in rain 15Z-18Z Saturday through the remainder of the day. Surface winds S/SE 7 knots or less today into tonight...then increasing to 10 to 15 knots mid-morning Saturday with a few gusts in the 20 knot range.

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MARINE

High pressure at the surface and aloft will continue to weaken today and a frontal system will approach the offshore waters late tonight. The associated warm front will lift across the coastal waters overnight with a trailing cold front moving onshore Saturday evening. This system is expected to produce small craft advisory winds across all waters beginning along the coast tonight then spreading to much of the interior waters on Saturday. Gusts could be near gale force at the east entrance to the strait and across portions of the coastal waters. A surface trough will move into the Oregon coastal waters on Sunday, but is expected to have little impact for area waters. A weakening front arrives on Monday. A broad surface ridge then builds over the waters moving into midweek for relatively quiet conditions before a late week frontal system arrives.

Seas look to remain in the 8-11 ft range through at least Tuesday, except up to 12-14 ft early on Saturday as the front moves through. Seas may ease below 8 ft mid-week.

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HYDROLOGY

Heavier precipitation over the weekend and early next week will force rises on the Skokomish River in Mason County with the river close to minor flood stage. Flooding is not expected elsewhere over the next 7 days.

SEW WATCHES/WARNINGS/ADVISORIES

WA...None. PZ...Dense Fog Advisory until 10 AM PST this morning for Puget Sound and Hood Canal.

Small Craft Advisory until 4 AM PST Saturday 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.