textproduct: Seattle/Tacoma

SYNOPSIS

A passing disturbance clips the northwestern part of the area, spreading a few showers and high clouds. Strong high pressure then 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.

UPDATE

Showers remain in progress this evening across the north interior. These will wrap up tonight as the disturbance passes. The remainder of the forecast below is on track with warmer weather and some fog/stratus next couple of mornings.

HPR

SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/

Strong high pressure building over the region for the next several days will usher in much warmer temperatures, well above seasonal normals. Expect the lowlands to reach well into the upper 50s to around 60s for afternoon temperatures each of the next few days. Some fog and low stratus likely develops each morning, so be alert for potentially restricted visibility during the early morning hours. Otherwise, dry conditions prevail through the short term period.

LONG TERM /FRIDAY THROUGH TUESDAY/

Ensemble guidance is in good agreement for a break in the warm and dry pattern starting around late Friday as the next disturbance begins to approach. Initially snow levels remain somewhat high and much of the precipitation will fall as rain, but snow levels lower to around 4000 ft by late in the weekend. This will bring a return of snow at times down to Stevens Pass. This will usher in a more active pattern through the start of next week marked by a return to near normal temperatures and more widespread precipitation chances. Will need to monitor another rise on the Skokomish River - see the HYDROLOGY section for more details. Otherwise, a more active and typical pattern is likely to emerge.

AVIATION

Light west to southwest flow aloft expected over Western Washington into Wednesday as an upper ridge axis builds over the interior West. The low level flow is weakly offshore. Varying amounts of high and mid level moisture will continue to filter across the area as a frontal system moves into the British Columbia coast late today. High level moisture will begin to thin early Wednesday and, coupled with weak surface flow with light south winds around or less than 5 kt, is likely to lead to expanded coverage of LIFR/IFR stratus and fog on Wednesday morning south of KPAE. The low clouds and fog may linger across the SW Interior of Western Washington much of the day.

KSEA...Varying amounts of high and mid level clouds will continue into tonight. As discussed above, the coupling of thinning high clouds and weak surface gradients lends moderate to high confidence in the return of fog and/or low clouds at the terminal again early Wednesday morning. Surface winds light and variable much of today trending more easterly tonight at 7 knots or less.

27/HPR

MARINE

Surface high pressure will remain centered over the interior with a broad trough of low pressure offshore producing varying degrees of offshore flow. 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.

Expect periods of night and morning dense fog over the next few days...especially portions of the interior waters.

27

HYDROLOGY

The Skokomish River has fallen below flood stage earlier today, and as a result, the warning has been cancelled. Mostly dry conditions continue through Friday, but another rise on the river is expected over the weekend. At this point, the forecast remains below flood stage for this next crest, but will need to continue to monitor the rainfall amounts and snow levels. Elsewhere, river flooding is not expected through the next seven days.

Cullen

SEW WATCHES/WARNINGS/ADVISORIES

WA...None. PZ...Small Craft Advisory until 4 PM PST Wednesday 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.