Marine Weather and Tide Forecast for Mercer Island, WA

SYNOPSIS
A cooler showery pattern will run into Tuesday, with a return to drier and warmer weather Wednesday and Thursday.
Precipitation chances return to the forecast by Friday into the weekend.

SHORT TERM /TONIGHT THROUGH THURSDAY/
An weak frontal system will move into western Washington this evening, bringing light rain and through Tuesday morning. The system continues to look very weak with high resolution ensembles like the HRRR showing all by a few lingering weak showers over the Cascades done by midday Tuesday. Highs will trend slight warmer Tuesday rising into the upper 50s to low 60s.

Upper level ridging returns to the region Wednesday, beginning a warming trend. Temperatures will climb into the mid to upper 60s, setting the stage for a warmer day still on Thursday.

LONG TERM /FRIDAY THROUGH MONDAY/
Thursday continues to look like the warmest day of the week with highs expected to climb into the upper 70s for much of Puget Sound and surrounding Cascade Valleys. NBM ensemble data showing some interior locations south of Puget having 60 to 90% chance of temperatures greater than 80 degrees. Even the coastal locations will get into the act with highs into the upper 60s. Temperatures look to moderate somewhat into the upper 60s and low 70s on Friday with increased onshore flow and an approaching frontal system which will bring another bout of cooler and showery Spring weather to the region Friday into Saturday.

AVIATION
A passing frontal system will continue to move through the region overnight through early Tuesday. Ceilings remain a mixed bag this evening with areas of VFR ahead of the front but MVFR and local IFR as you move west toward the coast and the steadier rain. Expect predominantly lower MVFR to IFR conditions in rain through most of the overnight and early Tuesday time period.
Lower ceilings then likely lift and begin to scatter later Tuesday.
On Tuesday, stronger westerlies through the Strait of Juan de Fuca bring gusts across KCLM and KNUW. This will bring a shift to northerly winds through the Puget Sound terminals during the day Tuesday.

KSEA...Ceilings likely fluctuate between lower VFR and MVFR this evening with leading rain as the frontal system continues to approach. Ceilings lower to around 015 after 09z through the overnight period, with rain tapering and slight improvement possible after 18z. More significant lifting in ceilings back to VFR expected after 21z, around the time of a wind shift to northerlies at around 8 kt.

MARINE
A frontal system will continue to work its way through the coastal waters this afternoon and tonight. The cold front will move through early tomorrow morning, quickly being replaced by high pressure during the day on Tuesday. Winds will ease Wednesday into Thursday. The next frontal system arrives Friday night into Saturday which looks to increase winds and may prompt another round of headlines during this time.

A push of westerlies down the Strait of Juan de Fuca is expected behind the front during the day Tuesday into Tuesday night, for which a small craft advisory is in effect.

Seas around 4 to 5 ft will increase tonight to around 6 to 8 ft by early Tuesday. Seas ease again Wednesday and Thursday back to 3 to 5 ft. Seas look to rise a bit with the next system Friday into Saturday but look to remain below 10 ft through the weekend.

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HYDROLOGY
No river flooding is expected over the next 7 days.

SEW WATCHES/WARNINGS/ADVISORIES
WA...None.
PZ...Small Craft Advisory from 8 AM Tuesday to 5 AM PDT Wednesday for Central U.S. Waters Strait Of Juan De Fuca-East Entrance U.S. Waters Strait Of Juan De Fuca.