textproduct: Seattle/Tacoma

SYNOPSIS

Strong high pressure builds over the region this week, bringing unseasonably warm and dry conditions to western Washington along with morning fog. A return to cooler and wet conditions occurs over the weekend.

SHORT TERM /TODAY THROUGH FRIDAY/

Strong high pressure remains in control for dry and mild weather through the end of the week. Mid and high clouds are streaming overhead but we will see decreasing clouds this afternoon with conditions becoming clear. With the mild air mass in place, max temperatures will track above average with highs in the 50s to lower 60s through Friday. Overnight lows will be a few degrees cooler with 30s around the south sound. 33

LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/

Wet and cooler weather returns over the weekend as the flow aloft turns to more zonal. Snow levels will lower Sunday night and Monday, around 3000 ft, with accumulating snowfall expected in the mountains and passes. Precipitation, heavy at times in the Olympics, will keep the Skokomish River in Mason County running high with minor flooding possible. More lowland rain and mountain snow moving through early next week due to a trough. 33

AVIATION

An upper ridge remains centered over the Great Basin today with broad troughing offshore producing light southwest flow aloft over Western Washington. Low level offshore flow continues. High level moisture filtering through the ridge is expected to thin today with continuing VFR conditions most areas into this afternoon. With clearing skies today, greater coverage of LIFR fog and low clouds is expected tonight for interior areas from central Puget Sound area southward into the Chehalis Valley. Most areas are expected to clear Thursday afternoon, though low clouds may linger much of the day across the Southwest Interior.

KSEA...VFR today with thinning high clouds. NBM only shows 20% probability of LIFR conditions Thursday AM, but the realistic probability is more in the 60% to 70% range between 11Z and 18Z. VFR expected again Thursday afternoon. Surface winds light and variable today becoming N/NE 7 to 10 knots on Thursday morning.

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MARINE

SCA remains in effect for the coastal waters - primarily due to seas through at least Thursday. Surface high pressure will remain centered over the interior with a broad trough of low pressure offshore producing varying degrees of offshore flow across area waters. East winds may approach small craft advisory levels at the west entrance to the strait and adjacent coastal waters on Thursday. Active conditions well offshore will continue to produce hazardous seas over the coastal waters this week. A series of frontal systems will begin to reach area waters this weekend into next week with the next best chance of more widespread wind related headlines.

Dense fog will be a possibility over the inland waters through next couple of mornings.

McMillian

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...Small Craft Advisory until 4 PM PST Thursday for Grays Harbor Bar.

Small Craft Advisory until 4 AM PST Thursday 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.