textproduct: Seattle/Tacoma

SYNOPSIS

Warm conditions will continue today before a cool- down on Tuesday. Dry conditions will prevail through the week, with a gradual warming trend peaking on Friday. Chances for light lowland rain and mountain snow increase into the weekend.

SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/

The current forecast remains on track with no planned updates. 33

Previous discussion...Unseasonably warm conditions will continue today across the Puget Sound and southward, with highs on track to reach the upper 60s to lower 70s. As the high pressure ridge continues to progress inland today, onshore flow will resume along the coast, where temperatures will be limited to the mid to upper 60s.

Onshore flow will continue to increase tonight as an upper level low progresses inland over western Canada. Breezy westerly winds will pick up tonight through the Strait of Juan de Fuca and along the Pacific Coast and northern Interior coastlines as a result. This system will also bring much cooler air into western Washington, with highs returning to near normal in the mid to upper 50s on Tuesday.

As a low pressure system stalls offshore of California, dry northwesterly flow will develop over the Pacific Northwest by Wednesday. With cooler overnight temperatures near freezing, frost may develop across portions of the region Wednesday morning that may impact sensitive crops and plants. Temperatures will quickly warm by the afternoon, with highs reaching the upper 50s to lower 60s under clear skies.

LONG TERM /THURSDAY THROUGH MONDAY/

The upper level pattern will remain fairly steady through Thursday, with northwest flow aloft and highs in the mid to upper 60s across the Interior. Forecast confidence decreases into Friday, with some models maintaining dry conditions across the Pacific Northwest while others bring a cutoff low inland across western Washington. Chances for rain will increase into the weekend, with a large spread in temperatures. Ensembles favor a more active pattern developing over the weekend, with cooler temperatures and light lowland rain and mountain snow.

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AVIATION

Westerly flow aloft becoming more northwesterly into Tuesday. Onshore flow present as the lower levels. Widespread VFR conditions in place with scattered high clouds overhead. There are isolated patches of MVFR conditions along the coast, but nothing impacting TAF sites. This VFR will persist into tonight, however convergence is expected to develop overnight which may impact the Puget Sound terminals. There is low confidence but low-end VFR to high-end MVFR cigs are possible for KSEA, KBFI and KPAE overnight into Tuesday morning with IFR to LIFR again possible for KHQM by Tuesday morning.

KSEA...Surface winds W/NW this evening before shifting more N/NW tonight. VFR this evening and early tonight but a 25% chance of MVFR cigs are possible into early Tuesday morning. If manifest, VFR cigs are likely to return in the usual 18-20Z window.

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MARINE

Onshore winds are increasing as a front passes by to the north and stronger high pressure builds in behind it. Small Craft Advisory remains for the coastal waters, West Strait, and Admiralty Inlet. A new SCA has been issued for the Northern Inland waters this evening into Tuesday morning. The Gale Warning remains for the Central/Eastern Strait. Seas are also going to increase tonight, with 9-11 ft waves expected. The northernmost outer coastal zone could see seas up to 15 feet late tonight as it is closer to the path of the low pressure system. Winds of 25 to 35 kts are possible with the occasional gust to 40 kt possible. Winds will slowly ease on Tuesday and remain relatively light through the rest of the week as high pressure remains in place over the northeast Pacific.

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HYDROLOGY

No river flooding is expected over the next 7 days.

SEW WATCHES/WARNINGS/ADVISORIES

WA...None. PZ...Small Craft Advisory until 2 PM PDT Tuesday 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-West Entrance U.S. Waters Strait Of Juan De Fuca.

Gale Warning until 5 AM PDT Tuesday for Central U.S. Waters Strait Of Juan De Fuca-East Entrance U.S. Waters Strait Of Juan De Fuca.

Small Craft Advisory until 9 AM PDT Tuesday for Northern Inland Waters Including The San Juan Islands.

Small Craft Advisory until 5 AM PDT Tuesday for Admiralty Inlet.