textproduct: Seattle/Tacoma

SYNOPSIS

A front will move over Western Washington today. The front will lift north tonight ending up in British Columbia Wednesday. A cold front will stall offshore Wednesday into Thursday. What is left of the front moving through Thursday night. Additional weather systems will move through Friday through Sunday. An upper level trough will move over the area Sunday night and Monday.

SHORT TERM /TODAY THROUGH THURSDAY/

Satellite imagery shows cloudy skies over Western Washington early this morning. Doppler radar has rain out ahead of the next system reached the coast around 3 AM/11Z. Temperatures were in the mid 40s to lower 50s.

Juicy system moving into Western Washington today. IVT values in the 800-1000 kg/m/s range making for a rainy day across the area. Southwesterly winds aloft will create the usual rain shadow northeast of the Olympics but with the air mass so moist even that area will fill in with rain later today. In addition to the rain, winds will be increasing later this morning into the afternoon hours. Model 925 mb winds 40-50 knots along the coast and just slightly weaker over the Northwest Interior beginning around 21Z. These winds will mix down towards the surface at times. The wind advisory for the coastal beaches and Northwest Interior beginning at 1 PM will remain in effect for gusts as high as 50 mph. The combination of winds, waves and lower surface pressure around the time of high tides will produce some minor coastal flooding along the ocean beaches. Inundation of 1.5 to 2 feet above ground levels is possible between 10 AM and 3 PM. Highs today in the mid 50s to lower 60s.

Front hanging over Western Washington this evening before lifting north overnight with rain chances becoming confined to west of Puget Sound and the Northwest Interior by early Wednesday morning. Front still close enough to keep windy conditions going along the coast and in the Northwest Interior. With the cloud cover and southerly winds it is going to be a mild night with lows in the lower to mid 50s. Record high minimums are possible.

Little change in the pattern Wednesday with the front to the north and a cold front stalled offshore. Rain along the coast and over the Olympics continuing with cloudy skies over most of the remainder of the area. Breezy southerly winds continuing throughout the day warming daytime temperatures into the 60s. Record highs are also possible.

Cold front remaining stalled offshore Wednesday night but not far enough off the coast to keep rain away for the coastline. Winds easing Wednesday evening with surface gradients relaxing and winds aloft decreasing. Plenty of cloud cover over the area making for another mild night with lows near 50.

Stalled cold front becoming more north south oriented Thursday as an upper level trough behind the front digs south offshore. Front will still be close enough to give locations west of Puget Sound more rain. Mild temperatures continuing with highs in the upper 50s to mid 60s. Felton

LONG TERM /THURSDAY NIGHT THROUGH MONDAY/

Models in good agreement with the stalled front getting kicked inland Thursday night as the flow aloft consolidates over the Eastern Pacific. Earlier model solutions indicated more of an atmospheric river pattern with the river getting stuck over the area Friday and Saturday. Model solutions are still wet for the Friday through the weekend but instead of an atmospheric river the solutions now favor a pair of wet and windy frontal systems Friday and again Saturday night and Sunday. Upper level trough trailing the front for Sunday night and Monday. Snow levels remaining above pass levels until the upper level trough arrives Sunday night lowering the snow level down to the 3500 to 4000 foot range. Felton

AVIATION

Ceilings will continue to fill in and lower this morning as the next system moves in and brings the next round of rain which will persist through much of the day today. MVFR conditions are already being observed on the coast, and will spread to include the rest of the area by 15Z this morning. Some periods of localized IFR conditions cannot be ruled out. Ceilings look to gradually improve to low-end VFR from south to north this evening for the interior terminals as the rain begins to lift north and taper off. MVFR conditions look to remain along the coast. South/southeasterly winds will build this morning to around 10-15 kt and remain fairly steady through the period. Gusts up to 20-25 kt will be possible area-wide, with gusts increasing up to 35 kt along the coast and north interior locations tonight.

KSEA...VFR conditions early this morning, through deteriorating to MVFR btwn 15-17Z this morning as rain moves through the terminal. Low chances for IFR conditions (around 20%) through 21z. Ceilings look to gradually raise this evening as rain tapers off, with VFR conditions expected after around 03Z tonight. Winds remain S/SE 8- 12kt with gusts up to 20 kt possible at times this afternoon and into tonight.

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MARINE

Winds will continue to increase over the area waters through this morning and afternoon, peaking this evening and persisting through the overnight hours tonight into early Wednesday. Winds will reach up to gale force across the coastal waters and the East Strait of Juan de Fuca, with Small Craft Advisories from Admiralty Inlet through the Northern Inland Waters as well. Winds will start to very slowly ease throughout the day Wednesday, with winds finally easing below advisory thresholds area-wide by Wednesday evening as the stalled front offshore causing these winds falls apart.

Seas around 9 to 10 ft will rise this morning to 16 to 19 ft this afternoon and evening both due to the stronger winds and another westerly swell group arriving. Seas will remain high through Wednesday morning before slowly easing throughout the day Thursday, through remaining above 11-13 ft.

The next stronger low pressure system begins to move into the coastal waters and increase the area winds late Thursday night into Friday. Winds look to peak Friday morning, with guidance still showing 60-75% chances for storm force wind gusts over the coastal waters. Winds look to ease slightly Friday night before another wave brings another round of strong winds on Saturday (40-55% chc of storm force gusts) and into Saturday night. Winds look to finally ease below thresholds late Sunday as the low broadens and weakens as it moves onshore.

Guidance has shifted the largest waves slightly farther south towards southern Washington and Oregon, but remains very confident (60-80%) in seas building above 20 ft on Friday, with GEFS and ECMWF probabilities showing 25-35% chances of seas above 25 ft. Slight shifts in the low tracks will determine where the dynamic fetch effects will be maximized from these systems, with seas nearing or exceeding 30 ft still not out of the equation, especially towards the southern portions of the waters.

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HYDROLOGY

A flood watch has been issued for Mason county for the possibility of the Skokomish River flooding with this next round of rain. The buffer from the dry October is gone with the river only dropping to around a foot and a half below flood stage after this recent rain event. As mentioned earlier this is a juicy system moving into the area today. Model 850 mb winds 40 to 50 knots out of the southwest creating good orographics over the south slopes of the Olympics. Snow levels will also be high, around 9000 feet. Forecasted rain amounts for the 24 hours between 4 AM today and 4 AM Wednesday along the south slopes 2.5 to 4 inches. With the elevated snow levels and the river running high already there is a good chance the Skokomish river will reach flood stage this evening or in the early morning hours Wednesday. Another round of rainfall with the system Friday could also push the Skokomish back above flood stage.

River flooding not expected on the other rivers in the area in the next 7 days. Felton

SEW WATCHES/WARNINGS/ADVISORIES

WA...Wind Advisory from 1 PM this afternoon to 7 PM PST Wednesday for Grays Harbor County Coast-Island County-Lowlands of Western Skagit and Northwestern Snohomish Counties- Lowlands of Western Whatcom County-Northern Washington Coast-San Juan County.

Flood Watch from this evening through Wednesday evening for Foothills of the Western and Southern Olympic Peninsula- Middle Chehalis River Valley-Olympia and Southern Puget Sound-Olympics-Southern Hood Canal-Willapa and Black Hills.

Coastal Flood Advisory from 10 AM this morning to 3 PM PST this afternoon for Grays Harbor County Coast-Northern Washington Coast.

High Surf Advisory from 10 AM this morning to 10 AM PST Wednesday for Grays Harbor County Coast-Northern Washington Coast.

PZ...Small Craft Advisory until 7 PM PST Wednesday for Admiralty Inlet-Grays Harbor Bar-Northern Inland Waters Including The San Juan Islands-West Entrance U.S. Waters Strait Of Juan De Fuca.

Gale Warning until 7 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-East Entrance U.S. Waters Strait Of Juan De Fuca.

Small Craft Advisory until 4 AM PST early this morning for Puget Sound and Hood Canal.