textproduct: Seattle/Tacoma

SYNOPSIS

Mountain snow and spotty lowland rain showers will dwindle into Friday night. A trend towards drier conditions then emerges over the weekend and continue into the first half of next week before the next front arrives around midweek. Near average temperatures expected throughout the period.

UPDATE

Quiet morning across western Washington. A few showers remain across the north interior but otherwise low clouds and dry conditions are in place. No significant weather impacts are expected today. The current forecast is on track and no updates are planned. -Wolcott-

SHORT TERM /TODAY THROUGH SUNDAY/

The forecast has been a synonymous with a broken record the last few days. However, pattern progression will be met here in the short term - let's dive in. An upper-low well offshore will begin it's gentle track landward today. Accompanying it to the north is an upper-ridge stretching into the Bering Sea, beginning to position itself over the Gulf of Alaska. We'll remain under northwesterly flow aloft as light spotty shower activity continue today (snow for elevations above 3,000 ft). A weak convergence zone may also develop into the evening across the Puget Sound region but met with no impacts. Tonight, conditions are slated to dry out completely with low temperatures falling into the lower to upper 30s. NBM is showing a 50-70% chance of overnight lows dropping below 32 F throughout the Chehalis River valley along with a 30-40% chance for the Cascade foothills on Saturday morning.

The aforementioned low center becomes well ingested into the mean-flow later on Saturday into Sunday. Here, it'll loom just off the CA/OR coast with upper-level ridging over the Gulf of Alaska. Conditions will remain dry and trend that way into next week. High temperatures are to top out in the upper 40s to near 50 F with overnight lows cooling lower into the 30s each night.

LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/

Ensembles suggests the upper-level pattern will continue to progress in the long-term forecast. The aforementioned cut off low will track inland over N. California/S. Oregon on Sunday night - early Monday morning. An upper-ridge will gradually position over the PNW by early next week. Daytime highs are slated to remain around average with cool overnight lows in the lower to mid 30s. The next front looks to arrive around midweek with a chance of widespread lowland rain and mountain snow.

AVIATION

West to northwest flow aloft will continue today as the region remains on the periphery of a frontal system moving into British Columbia. A mixed bag of of VFR and MVFR ceilings this morning will lift to VFR most areas mid afternoon into the evening. Ceilings will deteriorate to low MVFR or occasional IFR areawide overnight before scattering out Saturday afternoon.

KSEA...MVFR ceilings will lift to VFR after 21Z this afternoon then lower back to low MVFR or tempo IFR 10Z-20Z Saturday. Low clouds are expected to scatter out Saturday afternoon. Surface winds S/SW 7 to 10 knots through this evening...then backing to N/NE overnight and rising to 8 to 12 knots Saturday afternoon.

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MARINE

Surface high pressure will build into the waters today, with onshore flow gradually easing through this afternoon. Small Craft Advisory wind gusts will continue at times for the central Strait of Juan de Fuca today, with isolated SCA gusts for the eastern Strait of Juan de Fuca. Winds will then transition more northerly or weak offshore over the weekend. The next frontal system looks to move into the waters Tuesday into Wednesday next week.

Seas will hover near 10 feet for the outer Coastal Waters through today, before subsiding back into the 4 to 7 foot range over the weekend through Tuesday. JD

HYDROLOGY

No river flooding is expected during the next seven days.

SEW WATCHES/WARNINGS/ADVISORIES

WA...None. PZ...Small Craft Advisory 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 James Island To Point Grenville 10 To 60 Nm-Coastal Waters From Point Grenville To Cape Shoalwater 10 To 60 Nm.