textproduct: Seattle/Tacoma

SYNOPSIS

A warm front has introduced a very mild air mass to Western Washington with near record high temperatures expected today. A cold front will stall offshore into Thursday with mainly dry conditions for interior areas and light rain at times near the coast. A series of frontal systems will bring a return of widespread rain and occasionally windy conditions Friday into early next week.

SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/

Western Washington sits in the warm sector today with a warm front north into B.C. and a cold front stalled offshore. We are seeing very mild conditions with temperatures in the 60s and a few spots breaking daily highs by a degree or two. Meanwhile, it's still windy along the north coast and north interior but winds will be easing this afternoon - the Wind Advisory will expire at 4 PM today as planned.

The cold front remains stalled offshore on Thursday with another mild day planned for western WA. Forecast highs are in the lower 60s or around 5-10 degrees warmer than average. A few light showers may clip the coast, otherwise it'll be dry in the interior.

A deep, stacked, low pressure center will shift E/SE toward WA on Friday, slowly pushing a front inland. While most of the rain will be along the coast, the interior will also see light accumulations. A tight pressure gradient will lead to gusty winds along the coast with gusts to 35-45 MPH. It'll be gusty too across the Cascades, gaps, and foothills with east winds to 20-30 MPH. In addition, high tides and lower pressure may lead to minor coastal flooding Friday morning. The main area is the shoreline and beaches around the Salish Sea during the time of high tide. 33

LONG TERM /SATURDAY THROUGH WEDNESDAY/

Low pressure (from Friday) will shift inland Friday night into Saturday, with another strong Pacific frontal system right at its heels. Coastal flooding remains a concern on Saturday morning too. This second system will bring more lowland rain and gusty winds to the area Saturday/Saturday night. Highest winds will be along the coast with S/SE gusts to 40-50 MPH. It will be windy in the interior as well with winds 20-40 MPH. Troughing keeps the area wet through Sunday. Rain-wise, we're looking at another 1-2" along the coast this weekend with 0.50-1.00" in the interior. Additional rainfall in the Olympics will keep the Skokomish River running high with flooding possible. Moving forward, showers continue into Monday with weaker troughing overhead. A weak front heads to our south by midweek. 33

AVIATION

Generally VFR this afternoon with MVFR along the Pacific Coast as a stalled frontal system continues to spread rain showers over the western Olympic Peninsula. Gusty southerly winds will gradually ease throughout the afternoon and become fairly light across the interior overnight. This will likely generate areas of IFR fog and low clouds west and south of the Puget Sound early Thursday morning, staying west of KSEA/KBFI. Showers will continue off and on along the coast through Thursday afternoon ahead of a stronger frontal system moving inland late Thursday.

KSEA...VFR with varying amounts of high and mid level clouds today. Surface winds south to southeasterly 7 to 10 knots with occasional gusts to 20 kt this afternoon easing to 6 knots or less tonight. Fog is not expected to impact the terminal overnight, though patchy fog may form near the vicinity.

27/15

MARINE

Strong winds will continue to persist across the coastal waters and northern inland waters today as a cold front remains stalled offshore. This front will weaken as it slowly drifts onshore this evening, allowing winds to slowly ease this evening into early Thursday morning. As a result, Gale Warnings for the coastal waters and East Strait of Juan de Fuca, and Northern Inland Waters, and Small Craft Advisories for Admiralty Inlet will continue through this evening. Seas generally around 15 to 18 feet this afternoon will gradually ease to around 12 to 15 feet on Thursday, with severe bar conditions easing to rough into Thursday at Grays Harbor.

A pair of strong low pressure systems will move across the coastal waters late Thursday night into Friday, with the second moving through Saturday night into Sunday. Winds will begin to increase across the area waters by the afternoon Thursday. Gales will begin as early as Thursday afternoon, peaking overnight into early Friday morning. Guidance continues to indicate 50-70% chances for storm force gusts over the outer coastal waters, though higher end gale force winds continue to be more likely along the inner coastal waters. A Gale Watch remains in effect, likely to be upgraded with additional Small Craft Advisories elsewhere.

Seas once again will build over the coastal waters on Friday. With the low center tracking closer towards our area, that will send the largest waves farther south towards Oregon. That being said, very large seas are expected, with ensemble guidance continuing to show very high confidence in seas above 20 ft by Friday evening, with a 25-35% chance of seas above 25 ft through Saturday morning. Dominant periods will be long but have come down slightly, in the 14-16 second range. Seas look to briefly ease Saturday morning below 20 ft before another system will send another round of large, long period waves on Sunday with high confidence in seas above 20 ft with chances of seas exceeding 25 ft through early Monday.

With these systems, slight shifts in the low tracks will determine where the strongest wave generation/dynamic fetch regions will be. While it is looking more likely that the largest waves will be aimed towards Oregon and California from the Friday/Saturday system, the Sunday/Monday system favors a more northward track with the largest waves aimed towards the Washington coast. There is a 5-10% chance of waves exceeding 30 ft at the peak wave height Sunday night.

62/15

HYDROLOGY

The Skokomish River is receding and will fall below flood stage tonight. Heavy rainfall this weekend will bring renewed potential for flooding.

River flooding is not expected on the other rivers in the area in the next 7 days at this time.

SEW WATCHES/WARNINGS/ADVISORIES

WA...Wind Advisory until 4 PM PST this afternoon 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.

High Surf Advisory until 4 PM PST this afternoon for Grays Harbor County Coast-Northern Washington Coast.

PZ...Small Craft Advisory until 1 AM PST Friday for Grays Harbor Bar.

Small Craft Advisory until 4 PM PST Thursday for West Entrance U.S. Waters Strait Of Juan De Fuca.

Gale Warning until 10 PM PST this evening for East Entrance U.S. Waters Strait Of Juan De Fuca-Northern Inland Waters Including The San Juan Islands.

Small Craft Advisory until 10 PM PST this evening for Admiralty Inlet.

Gale Warning until 7 PM PST this evening 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.

Small Craft Advisory from 7 PM this evening to 4 PM 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.

Gale Watch from Thursday afternoon through late Thursday night 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.