textproduct: Seattle/Tacoma

SYNOPSIS

Multiple Pacific storms will impact western Washington this week and weekend for gusty winds, lowland rain and high elevation mountain snow. Large swells will reach the coast on Friday.

SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/

Our next Pacific frontal system is upon us with rain spreading inland this afternoon. The air mass is slightly unstable with a chance of thunderstorms across SW WA (mainly this afternoon and evening). Expect windy conditions along the coast and North interior with south winds gusting to 30-35 MPH.

Another deep low spins over the NE Pacific on Tuesday and Wednesday for another round of gusty winds, lowland rain and high elevation snow. Winds will be strongest along the coast and North Interior with south/southeast wind gusts to 40-50 MPH - Wind Advisories are in effect. Winds will stay gusty through Wednesday afternoon then ease Wednesday night. In addition, minor coastal flooding is possible around the time of high tide Wednesday morning for the San Juans and western Whatcom county. 33

LONG TERM /THURSDAY THROUGH MONDAY/

A trio of strong Pacific systems are poised to impact Western WA Friday through Sunday. The main impact will again be strong winds, especially over the coast where gusts may exceed 50 MPH. We may also see gusty winds to 30-40 MPH in the interior as well. These systems will also generate large swells that will reach the WA coast Friday with seas over 20 ft possible. Rainfall will be heavy at times along the coast and over the Olympics. This may bring the Skokomish River close to minor flood stage. We are also closely monitoring the storm tide predictions as well as a few locations may see minor coastal flooding on Saturday. The last system moves in on Sunday - more wind and rain - with the weather easing moving into Sunday night and Monday. 33

AVIATION

A frontal system will continue to move across the terminals, with widespread rain increasing. VFR ceilings will continue through the afternoon and evening, before decreasing to MVFR later this evening and overnight. Reduced visibilities have been observed with heavier pockets of rain down to to 3-5 mi. Pockets of IFR/LIFR are expected in the mountains. Overnight the ceilings are expected to lift up to low-end VFR, with an additional front passing through late Tuesday with more rain and lowering ceilings/visibilities back down to MVFR. The threat of thunder remains less than 20% with activity this evening/Tuesday. Winds will generally remain out of the southeast or southwest, with the strongest winds this evening/Tuesday morning, and again Tuesday evening. Gusts up to 20-30 kt with higher gusts to 35 kt along the coasts.

KSEA...Rain arriving this afternoon, with ceilings lowering to MVFR shortly after 00Z. Brief increase to VFR appears likely after 06Z before the next round of rain arrives Tuesday morning (after 15Z), then conditions will drop back down to MVFR. Heavier rain rates may drop visibilities down to 3-5 mi. Southeast to southwest winds with the strongest winds this evening, and Tuesday afternoon/evening (gusts up to 20-25 kt).

HPR

MARINE

A series of frontal systems will impact the waters through the week. Widespread rain will pass over the waters at times, with rates potentially becoming heavy enough to drop visibilities significantly for mariners. There is a 20% chance of thunder for portions of the coastal waters with the front moving through this evening, and again Tuesday afternoon into Wednesday.

Widespread gusty southerly winds will continue for much of the week across the majority of the waters. Winds with the front moving through Monday afternoon will remain in the 20 to 30 kt range for the coastal waters and west Strait of Juan de Fuca, and Puget Sound through the Northern Inland Waters (including the east Strait of Juan de Fuca and Admiralty Inlet). A stronger system on Tuesday into Wednesday will produce widespread and frequent gale force gusts for the coastal waters and east strait. Wind gusts will likely remain above 20 kt through Friday with another stronger system producing additional gale gusts for the coastal waters and east Strait of Juan de Fuca, with a similar system on Saturday into Sunday. Models have winds finally decreasing below 20 kt early next week.

Seas: 10-12 ft tonight through Tuesday, increasing to 17 to 19 ft late Tuesday into Thursday before decreasing to 10 to 14 ft Thursday. Models have a significant push up to 20 to 23 ft Friday into the weekend with seas decreasing on Monday back down to 10 to 14 ft.

HPR

HYDROLOGY

River flooding is not expected through Thursday. Atmospheric river hanging up over the Olympics Friday into Saturday. Current rainfall forecast for the South Slopes of the Olympics in the 3 to 4.5 inch range. Snow levels are not exceeding high, 5000 to 6500 feet, but add in the additional rainfall leading up to the event this amount of rain will bring a flooding threat to the Skokomish River at the end of the week.

River flooding not expected on the remainder of the rivers in the area Friday through Sunday. Felton

SEW WATCHES/WARNINGS/ADVISORIES

WA...Wind Advisory from 1 PM Tuesday 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.

PZ...Small Craft Advisory until 4 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 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-East Entrance U.S. Waters Strait Of Juan De Fuca.

Small Craft Advisory until 4 AM PST Tuesday for Puget Sound and Hood Canal.