textproduct: Seattle/Tacoma

SYNOPSIS

Upper level ridge exiting the area this morning. Upper level disturbance moving by to the north later this afternoon and evening inducing a marine push tonight. Upper level ridge building well offshore Tuesday with stationary upper level low off Northern California giving Western Washington dry northwesterly flow aloft through Friday. Upper level low moving out of the Gulf of Alaska reaching the area over the weekend.

SHORT TERM /TODAY THROUGH WEDNESDAY/

Satellite imagery shows just some high clouds over Western Washington early this morning as the upper level ridge over the area moves east. Temperatures at 3 am/109z were in the 40s and lower 50s.

Upper level ridge continuing to move east today with low level offshore flow turning onshore this morning. Stratus currently as far north as Newport will continue moving north but not reach the Washington coast. The transition to onshore flow will cool high temperatures along the coast into the mid and upper 50s. Marine air associated with the onshore flow not getting very far inland this afternoon keeping highs over the interior in the 60s and lower 70s.

Low level onshore flow continuing to increase tonight as upper level shortwave moves by to the north. Gale force westerly winds down the Strait of Juan de Fuca and breezy southwest winds over the Lower Chehalis Valley and Southern Puget Sound. Increasing clouds overnight with lows in the mid 30s to lower 40s.

Upper level ridge building well offshore Tuesday with upper level low remaining stationary off the Northern California coast giving Western Washington dry northwesterly flow aloft. Decreasing clouds with highs much cooler for the interior, mid to upper 50s. Highs along the coast in the mid 50s.

Little change in the pattern Tuesday night and Wednesday. Under mostly clear skies lows will be chilly Wednesday morning. The colder locations in the South Puget Sound and Southwest Interior will be near freezing. Lows in the mid 30s to near 40 for the remainder of the area. Highs Wednesday mid 50s to lower 60s. Felton

LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/

Models remaining in good agreement with the upper level ridge offshore and the upper level low off Northern California remaining in place into Friday. Dry northwesterly flow aloft continuing over the area. Slight warming trend with highs in the upper 50s to mid 60s. Lows in the 30s and lower 40s.

Models in much better agreement over the weekend. Cool upper level low dropping down out of the Gulf of Alaska moving over Western Washington with showers and cooler temperatures. Highs lowering into the 50s Saturday and lower to mid 50s Sunday. Cloud cover will keep lows in the upper 30s to mid 40s.

AVIATION

High pressure will be weakening and shifting today as a system passes to the north. Middle and high clouds will progress through the region this afternoon. Slight chances for showers will be confined more to the central and north Cascades this evening. Strong westerly winds are set to begin through the Strait of Juan de Fuca this afternoon, leading to some potentially gusty winds in areas from PAE north. Otherwise, surface winds will be WSW at 6-10 kts today, turning back to a northerly in the evening between 5-8 kts, around 00-03Z in Puget Sound. Clouds along the coast this morning could be somewhat lower with some visby restrictions possible, but likely not enough cover to constitute a true cig. Otherwise, VFR expected through the rest of the TAF period.

KSEA...Light northwesterly winds early this morning will transition more to a WSW wind by 12-13Z ahead of the passing frontal system. Surface wind speed will increase from 4-6 kts to 10-12 kts after 20Z. Post frontal north/northwesterly winds are expected after 02Z this evening. A mix of middle and high clouds are expected throughout the period, but with the lowest not dipping much below 10 kft. Confidence is low (less than 15%) in any precipitation reaching the terminal today.

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MARINE

Broad high pressure remains in place across the area today with a weak thermal trough build up along the west coast, keeping winds northerly. Winds will increase this afternoon as a front passes by to the north and stronger high pressure builds in behind it. Small Craft Advisory has been extended to the southern coastal zones as winds are expected as well as into Admiralty Inlet. Seas are also going to increase today, with 9-11 ft seas expected. The northernmost outer coastal zone could see seas up to 15 feet as it is closer to the path of the low pressure system. With the onshore gradients getting to plus 5-6 mb, have upgraded to a gale warning in the central and eastern Strait this afternoon. Winds of 25 to 35 kts are possible with the occasional gust to 40 kt possible. Winds will continue to turn down into the Puget Sound. Winds will slowly ease on Tuesday and remain relatively light through the rest of the week as high pressure remains in place over the northeast Pacific.

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HYDROLOGY

No river flooding the next 7 days.

SEW WATCHES/WARNINGS/ADVISORIES

WA...None. PZ...Small Craft Advisory from 2 PM this afternoon to 2 PM PDT Tuesday 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- West Entrance U.S. Waters Strait Of Juan De Fuca.

Gale Warning from 11 AM this morning to 5 AM PDT Tuesday for Central U.S. Waters Strait Of Juan De Fuca-East Entrance U.S. Waters Strait Of Juan De Fuca.

Small Craft Advisory from 5 PM this afternoon to 5 AM PDT Tuesday for Admiralty Inlet.