textproduct: Seattle/Tacoma

SYNOPSIS

Weak high pressure continues to bring dry conditions over the region today. A system entering on Tuesday will bring lowland rain, high elevation mountain snow, and gusty winds over the area. Unsettled weather continues on Wednesday with showers lingering. Conditions will dry out and warm up heading into the end of the week.

SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/

Recent satellite imagery shows an abundance of high level clouds streaming into western Washington ahead of a system offshore. Weak high pressure this afternoon will keep conditions dry and calm, with high temps in the mid 50s.

A moist frontal system will enter the area Tuesday morning, bringing lowland rain, high elevation mountain snow, and breezy winds. The main threat will continue to be gusty south winds slated to arrive Tuesday morning and afternoon. The areas that will see the strongest wind gusts will be areas primarily along the coast, along with locations in the North Interior (Whidbey Island, San Juans, western Whatcom County). Probabilities of gusts over 45 mph per the HREF. A Wind Advisory has also been issued for these locations. Elsewhere, widespread breezy winds can be expected up to 40 mph at times through the interior.

Snow levels generally around 3000 feet early Tuesday will rise upwards to 6000 feet in the Cascades, limiting snow to the higher elevations. Onshore flow continues into Wednesday with post frontal showers across the area. Snow levels will lower to 2500 feet with some accumulations in the passes. Latest guidance depicts a convergence zone developing early Wednesday evening that could locally enhance snow amounts in the Cascades, especially at Stevens Pass. With the air mass being slightly unstable, an isolated thunderstorm or two can be possible Wednesday afternoon but confidence is low.

LONG TERM /THURSDAY THROUGH MONDAY/

Conditions begin to dry out Thursday with some lingering shower activity in the mountains. High pressure will shift inland starting on Friday for slightly warmer conditions across much of the area. High temperatures over the weekend look to range in the upper 50s into lower 60s for much of the interior. A trough will approach on Monday with a chance of rain and cooler temperatures.

Mazurkiewicz

AVIATION

Southwesterly flow aloft with VFR conditions through much of tonight. High ceilings will gradually lower through the evening to 4- 5 kt ft by around 13Z as a warm front moves into the area from the southwest. Expect MVFR ceilings along the coast with light rain by midmorning and midday for many interior locations. Light northerly low level winds will persist overnight then becoming southerly Tuesday morning - and strengthening mid day becoming gusty with widespread gusts 25 to 30 kt.

KSEA...VFR conditions with high clouds through the evening. Ceilings will lower, with a 30% chance of MVFR conditions by 15Z and an 80% chance by late morning. Light north-northeasterly winds will become southerly early Tuesday morning 6-8kt then 10-12kt gust 25kt by midday.

MARINE

Relatively light winds with seas 7 to 9 ft this afternoon and evening. An approaching system will move into the area early Tuesday, with the surface low tracking towards the northern point of Vancouver - followed by the cold front Tuesday evening. Winds will increase across area waters Tuesday morning, peaking first across the coastal waters Tuesday afternoon ahead of the frontal passage, then subsequently through the interior waters later Tuesday evening. Gale force winds will be likely across the coastal waters, as well as through the Puget Sound, Admiralty Inlet, East Entrance to the Strait of Juan de Fuca and the Northern Interior Waters. Seas will rise on Tuesday, peaking around 15-18 ft. Seas up to and exceeding 20 ft remain possible across the northwest outer waters. Winds will likely remain a bit elevated for much of Wednesday as strong onshore flow continues behind the system. More benign conditions Thursday through the end of the week as high pressure looks to redevelop across the area. Seas will slowly subside becoming 6-8 ft Thursday through the rest of the week.

HYDROLOGY

Flows on the Cedar River at Renton remain high, just below Minor Flood Stage due to dam operations. Small rises are expected with Tuesday's wetter system however additional flooding is not expected. 33/Mazurkiewicz

SEW WATCHES/WARNINGS/ADVISORIES

WA...Wind Advisory from 11 AM to 6 PM PDT Tuesday for Island County- Lowlands of Western Skagit and Northwestern Snohomish Counties-Lowlands of Western Whatcom County-Port Townsend Area-San Juan County.

Wind Advisory from 9 AM Tuesday to 3 PM PDT Wednesday for Grays Harbor County Coast-Northern Washington Coast.

PZ...Gale Watch from Tuesday morning through Tuesday afternoon for Admiralty Inlet-East Entrance U.S. Waters Strait Of Juan De Fuca.

Gale Watch from Tuesday morning through Tuesday evening for Puget Sound and Hood Canal.

Gale Watch from late tonight through Tuesday 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.