Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA

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243 FXUS66 KSEW 242131 AFDSEW Area Forecast Discussion National Weather Service Seattle WA 231 PM PDT Wed Jul 24 2024 .SYNOPSIS...
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Upper level trough over Western Washington through Thursday with a chance of showers north part. A weaker trough will take its place over the weekend into the first part of next week. Temperatures will be close to normal.
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&& .SHORT TERM /TONIGHT THROUGH SATURDAY/...
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An upper level low and onshore flow will give western WA generally mild weather over the next few days. Temperatures are in the 60s (coast) and 70s interior or close to late July normals. We will see a few showers as the trough moves overhead tonight and Thursday, with showers mainly over the coast and mountains. The North Cascades have the best shot at seeing wetting rains. Thursday will be a few notches cooler although still seasonably mild. A weak trough will remain over western WA Friday and Saturday as the upper low shifts NE toward northern Alberta/Saskatchewan. Temperatures will continue to track close to normal through the period. .LONG TERM /SUNDAY THROUGH WEDNESDAY/...Troughing remains over the region on Sunday for a repeat of mild, late July weather. We may tap into some moisture over the Pacific early next week (Mon- Tuesday night) for a chance of showers. There`s a 70% chance of seeing measurable precipitation through the period in the lowlands. The mountains have a 60-70% chance of seeing wetting rains (0.25" or more). Temperatures nudge upwards Wednesday afternoon with broad ridging over the Rockies. Around half of the ensemble runs have interior lowland temperatures in the lower 80s again. 33
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&& .AVIATION...
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West/southwest flow aloft with a large upper level trough over the region. In the low levels, southwesterly winds will transition to becoming northwesterly tonight as onshore flow increases behind a weak front currently moving through the area. Winds persist overnight, returning beck to southwesterly early tomorrow morning. Winds remain southwesterly tomorrow but gradually turning back to northerly tomorrow evening. Most locations are VFR this afternoon with a scattered mid-level cloud deck, with MVFR conditions on the coast associated with what is left of the front. Expecting increasing cloud cover tonight across the region. Increasing convergence overnight may allow for MVFR ceilings over Snohomish and Skagit counties. Low-end VFR ceilings are expected elsewhere. Skies will clear out and lift throughout the day tomorrow, with a return to VFR conditions everywhere tomorrow. KSEA...Mostly clear skies with increasing mid and high level clouds this afternoon. Ceilings developing and lowering overnight, through expected to remain above MVFR. VFR conditions return Thursday morning with gradual clearing. West/southwest winds turning northerly this evening before returning to southwesterly overnight. Winds will again gradually turn from southwesterly to northwesterly over the course of tomorrow, with speeds generally remaining in the 5 to 10 kt range. LH
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&& .MARINE...
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Surface high pressure will remain offshore over the eastern Pacific Ocean with low pressure inland, maintaining northwesterly onshore flow. A weak front currently over the coastal waters is rapidly dissipating as it moves onshore. The next frontal system may approach the region by the beginning of next week. Winds will continue to increase tonight through the Strait of Juan de Fuca. Widespread gusts to gale force, with sustained winds near or just below gale force. The Gale Warning remains in effect for the Central and Eastern Strait of Juan de Fuca, with a Small Craft Advisory as well for Admiralty Inlet. Additional westerly pushes down the Strait will continue through this weekend and into next week. Some may require additional headlines but none look to be as strong as tonight at this time. Seas remain 3 to 6 ft into next week. LH
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&& .FIRE WEATHER...
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We`re continuing to see benign fire weather conditions for the next several days. Stout onshore flow off the Pacific will keep concerns to a minimum. Isolated pockets of critical RH values are possible in the Cascade zones of 658 and 659 but, decent overnight recoveries are expected. 20-40% chance of showers overnight Wednesday into Thursday morning for the Northern Interior with little to no chance of wetting rain. The next threat for precipitation is favored to arrive Monday-Tuesday of next week with a better chance of wetting rain as widespread precipitation looks to be at play in what`s climatologically the driest time of the year. McMillian
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&& .SEW WATCHES/WARNINGS/ADVISORIES...
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WA...None. PZ...Gale Warning until 5 AM PDT Thursday for Central U.S. Waters Strait Of Juan De Fuca-East Entrance U.S. Waters Strait Of Juan De Fuca. Small Craft Advisory from 6 PM this evening to 5 AM PDT Thursday for Admiralty Inlet.
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