textproduct: Seattle/Tacoma

SYNOPSIS

A frontal system will produce another round of precipitation overnight into Thanksgiving Day. The weather pattern will trend drier and eventually cooler Friday into early next week.

SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/

Current forecast is on track with an area of low pressure and associated frontal system spreading rain across the area overnight into most of Thanksgiving Day. The surface low and front will weaken considerably by the time they move onshore tomorrow evening. Nonetheless, it'll be a soggy day tomorrow with precip decreasing by Friday morning as the system shifts eastward. Previous discussion follows with an update to the aviation portion. 27

Latest radar imagery shows shower activity pulsing up from the south and starting to approach our area. Rain will start for most of the area starting later this afternoon and evening as a frontal system spins offshore. High temperatures this afternoon staying in the low to mid 50s across the region, with overnight lows in the low to mid 40s.

Widespread steady rain will continue overnight and into Thursday as this low takes its time offshore. It looks like Thanksgiving day will have showers on and off throughout the day, with most of the area seeing precipitation - which could be locally heavy at times (areas in the Olympics and Cascades). Along with widespread precipitation, winds will be breezy at times, especially for areas along the coast and for portions of the interior. Rain and wind both took to taper overnight Thursday into Friday, with a drying trend looking to start up over western Washington.

LONG TERM /SATURDAY THROUGH WEDNESDAY/

Upper level ridging over the eastern Pacific looks to dry out conditions throughout the day on Friday and heading into the weekend. Some of the ensembles are hinting on a few weak impulses on Saturday that could spark some light showers across the area, but it is looking rather weak if it does materializes. Otherwise, conditions look to be mainly dry for the weekend, along with overnight temperatures getting cooler. Overnight temperatures on Saturday look to get down to the upper 30s, even mid 30s early Sunday morning. Areas near the water likely will be cooler overnight, and especially if cloud cover clears up, could anticipate temperatures dropping a bit more.

The upper ridge starts to shift eastward on Monday which leaves room for a weak frontal system to potentially cross over western Washington for another round of light rain. Ensembles are still trying to key in on this feature, but for now will leave mention of showers each day through Wednesday.

Mazurkiewicz

AVIATION

Westerly flow aloft will back to southwesterly overnight as an upper trough and frontal system offshore approach the area. A mixed bag of ceilings this evening is expected to solidify into mostly MVFR overnight as precipitation increases. MVFR in light rain will persist throughout Thanksgiving Day.

KSEA...Ceilings will lower overnight and become MVFR through most of Thursday in light rain at times. Surface winds N/NE 5 to 8 knots will shift to a more easterly direction Thursday AM. 27

MARINE

A bit of lull in the winds during the day today in between systems, but it's worth noting that seas over the coastal waters remain quite choppy with a dominant period around 7-9 second. Conditions continue to hold just short of advisory criteria, however. Another strong front will bring another round of advisory strength winds Thursday, along with seas building significantly into the 15-17 ft range (particularly the outer and southern coastal waters). At this point gales should remain over the offshore waters and the current SCA covers the coastal zones well, but occasional gusts to 35 kt can't be ruled out beyond about 35 NM from shore. Late in the week, high pressure begins to rebuild over the coastal waters into the weekend. Will need to monitor the strength of any northeast flow developing, but at this point strong Fraser outflow isn't particularly likely.

HYDROLOGY

Another frontal system will bring a round of rain to the region. Snow levels will remain above 5000 feet through Thursday evening, leaving the majority of the precipitation falling as rain. However, with expected rainfall amounts holding steady and topping out mostly in the 2 to 2.5 inch range with this system, confidence is increasing that we will not see any river flooding impacts. As a result, the flood potential outlook has been expired for Mason County.

SEW WATCHES/WARNINGS/ADVISORIES

WA...None. PZ...Small Craft Advisory from 4 AM to 4 PM PST Thursday for Central U.S. Waters Strait Of Juan De Fuca-West Entrance U.S. Waters Strait Of Juan De Fuca.

Small Craft Advisory from 1 AM Thursday to 4 AM PST Friday 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.