textproduct: Seattle/Tacoma

SYNOPSIS

Upper level ridge over the area shifting east this morning. Splitting weather system arriving tonight into Wednesday morning. A series of systems will reach the area Wednesday night through Friday night. An upper level ridge will try to build Saturday before another system later in the weekend.

SHORT TERM /TODAY THROUGH THURSDAY/

Satellite imagery shows mostly cloudy skies over Western Washington early this morning. Breaks in the cloud cover has allowed some locations to drop into the upper 20s. Cross cascade gradient down to -6 mb at 2 am/10z. Locations with some exposure to the increasing easterly winds, like Paine Field in Everett, still have temperatures in the lower 40s.

Upper level ridge over the area early this morning will be east of the Cascades before noon. Approaching front not making much eastward progress with the parent low well to the north, a wave developing on the backside of the front and the jet aimed at Northern California/Southern Oregon. Clouds thickening later today but rain chances with the system not beginning until this afternoon west of Puget Sound. Highs near 50.

What is left of the front reaching the coast overnight. Cross cascade gradients peaking out near -9 mb giving the Cascade foothills some gusty, 30 to 35 mph, easterly winds tonight. Rain slowly spreading across the area. It will be a close call if Seattle can record another dry dry to add on to the current 14 day dry streak with rain predicted to begin around midnight. Snow levels around 4000 feet but the easterly winds in the passes will create a shallow layer of cold air near the surface bringing up the possibility of freezing rain in Snoqualmie and Stevens Pass. Lows upper 30s to mid 40s.

Front falling apart over Western Washington Wednesday morning. Flow aloft consolidating over the Eastern Pacific with another system moving quickly towards the area. Rain out ahead of this system reaching the area in the afternoon. Cross cascade gradient trending towards zero with easterly winds in the passes easing. This should erode the shallow layer of cold air in the passes by afternoon ending the freezing rain threat. Highs near 50.

Warm front moving through Western Washington Wednesday night with the trailing cold front arriving Thursday keeping the wet weather in the forecast. Gusty southeasterly winds over the Northwest Interior, 30 to 35 mph, especially Wednesday night. Snow levels rising to 5000 to 5500 feet by Thursday. Lows in the mid 40s and highs in the lower 50s.

LONG TERM /THURSDAY NIGHT THROUGH MONDAY/

Extended models in good agreement with another frontal system Thursday night and Friday. Operational solutions build a ridge over Western Washington Saturday with a front stalled offshore. This is a good pattern for a very warm day this time of year. The weakening front moves inland late in the weekend. ECMWF ensembles in pretty good agreement with the operational run with very few wet solutions. The GFS ensembles are not as excited about the ridge with about half of the solutions remaining wet. Will keep a slight chance or chance of rain in the forecast through most of the weekend with the highest pops Sunday night. Upper level trough moving through Monday keeping precipitation in the forecast. Snow levels remaining above the passes through the period. Highs in the lower to mid 50s with the potential for some lower 60s Saturday if the ridge solution wins out. Lows mostly in the lower to mid 40s. Felton

AVIATION

An upper level ridge has shift inland as an upper level trough approaches from the northeastern Pacific. Southwesterly flow aloft will become more southerly throughout the day as a result. Conditions at the area terminals are primarily VFR, with mid to high cloud cover streaming in ahead of a frontal system that will move into western Washington this evening.

Winds will then increase to 10-20 kt (with gusts to 25-30 kt possible) by this evening as the front approaches. Rain looks to arrive at the coastal terminals by late afternoon (00-03Z) and then push inland into the interior by this evening (03-06Z). Conditions generally look to remain VFR with the arrival of rain tonight, but look to gradually decrease to MVFR overnight into Wednesday morning.

KSEA...VFR conditions expected to persist at the terminal through the day. Light S/SE winds will increase to 10-15 kt by this evening as the front approaches. Gusts to 20-25 kt will be possible at times tonight as the front moves through. Rain will likely make it into the terminal between 03-06Z. MVFR conditions expected to develop at the terminal by Wednesday morning.

14/McMillian

MARINE

A frontal system will move across the area waters today, bringing southerly gales to the coastal waters throughout the day and to the eastern Strait of Juan de Fuca as it moves inland this evening. Small craft southeasterlies are likely along the western Strait of Juan de Fuca ahead of the front and are also likely along Admiralty Inlet and the Northern Inland Waters as the front moves inland tonight. Seas across the coastal waters will build from 3-6 ft this morning to 10-14 ft by tonight.

Another system will move across the area waters Wednesday into Thursday, which looks to bring another round of gales to the coastal waters and to the eastern Strait (where latest guidance indicates roughly a 50-70 percent chance of gales redeveloping). In addition to winds, seas will build across the coastal waters to 15-20 ft late Wednesday into Thursday.

The pattern will remain active over the weekend, with additional systems expected to move across the area waters. Seas will gradually subside on Friday, but look to remain elevated and range between 10-12 ft through the weekend.

14

HYDROLOGY

Multiple rounds of rain over the south slopes of the Olympics will cause the Skokomish River to rise beginning Wednesday. The river could reach flood stage as early as Thursday morning. More likely the river will reach flood stage later Thursday and remain over flood stage into Saturday. No river flooding expected on the remainder of the rivers. Felton

SEW WATCHES/WARNINGS/ADVISORIES

WA...None. PZ...Small Craft Advisory from 10 PM this evening to 4 PM PST Wednesday for Grays Harbor Bar.

Small Craft Advisory until 10 PM PST this evening for West Entrance U.S. Waters Strait Of Juan De Fuca.

Gale Warning from 7 PM this evening to 4 AM PST Wednesday for East Entrance U.S. Waters Strait Of Juan De Fuca.

Small Craft Advisory from 7 PM this evening to 4 AM PST Wednesday for Admiralty Inlet-Northern Inland Waters Including The San Juan Islands.

Small Craft Advisory until 1 PM PST this afternoon for Coastal Waters From Cape Flattery To James Island Out 10 Nm- Coastal Waters From James Island To Point Grenville Out 10 Nm-Coastal Waters From Point Grenville To Cape Shoalwater Out 10 Nm.

Gale Warning until 10 PM PST this evening for Coastal Waters From Cape Flattery To James Island Out 10 Nm-Coastal Waters From James Island To Point Grenville Out 10 Nm- Coastal Waters From Point Grenville To Cape Shoalwater Out 10 Nm.

Gale Warning until 10 PM PST this evening for Coastal Waters From Cape Flattery To James Island 10 To 60 Nm-Coastal Waters From James Island To Point Grenville 10 To 60 Nm- Coastal Waters From Point Grenville To Cape Shoalwater 10 To 60 Nm.