Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA
Issued by NWS Seattle/Tacoma, WA
448 FXUS66 KSEW 252200 AFDSEW Area Forecast Discussion National Weather Service Seattle WA 300 PM PDT Tue Jun 25 2024 .SYNOPSIS...High pressure remains in place with dry and warm conditions today. A shift in the pattern will bring the next upper trough to the Pacific Northwest, bringing cooler temperatures, breezy winds, and the return of precipitation. The cycle then repeats with dry and warmer conditions Friday ahead of the next disturbance that reaches the area over the weekend. && .SHORT TERM /TONIGHT THROUGH FRIDAY/...Warm and dry conditions across the area this afternoon as high pressure remains in placed over Western Washington. Temperatures are mostly in the 70s for the interior away from the water, with some pockets of cooler temperatures closer to the coast. Nevertheless, a change is in store as a look to the west will reveal leading clouds ahead of the next disturbance moving closer to the coastline. We`ll see this next upper trough slide through the region with an associated cold front sweep through the region. This will bring widespread cloud cover and showers through the day. Amounts near the coast and in the mountains may reach between a quarter of an inch and one half inch. Expect breezy winds to develop across the region this is front as well, followed by increasing post-frontal flow that will likely induce at Puget Sound Convergence zone by Wednesday evening.There is also a potential for isolated thunderstorms in the Cascades, with the highest chance in the North Cascades. The trough continues eastward into Thursday, but with continued onshore low-level flow expect plenty of lingering clouds and temperatures remaining below normal. High pressure rebuilds again Friday in between disturbances for a decrease in clouds and a return closer to normal temperatures. Some lingering showers in the mountains may persist, though. .LONG TERM /SATURDAY THROUGH TUESDAY/...The next disturbance clips the region by late Saturday or Sunday, providing another focus for precipitation though much less than what is expected Wednesday. Ensemble guidance in the extended continues to favor a rather unremarkable pattern with largely zonal flow with some chances (20-30%) on either side suggesting weak ridging or a few passing weak troughs through the region. On the whole, expect this to maintain temperatures generally somewhat close to normal and at least some showers chances at times for the early portion of next week. && .AVIATION...An upper level ridge will shift to the east tonight as an upper level trough approaches the Pacific Northwest. This will maintain S/SW flow aloft through the TAF period. Satellite this afternoon shows mostly clear skies across the interior, with increasing mid to high level clouds moving over the coast and areas north of KPAE. Conditions are VFR across the area terminals this afternoon and will remain so through the evening hours. Ceilings will gradually lower overnight into early Wednesday morning as a surface front approaches western WA. Expect ceilings to lower towards MVFR on the coast Wednesday morning as rain starts to move into the region. Surface winds generally persisting out of the N/NW at around 5-10 knots through tonight, easing overnight. Winds will transition to the S/SW early Wednesday, most likely between 12-15Z and increase to 10-15 kt. Gusts to 20-25 kt will be possible through the day Wednesday. KSEA...VFR conditions will continue through tonight. N/NW surface winds 7-12 kt will ease during the overnight period and transition to S/SW between 12-15Z. Winds will increase to 10-15 kt Wednesday morning, gusting to 20-25kt at times through the afternoon. Light rain looks to make its way into the terminal between 15-18Z and could briefly bring ceilings down to MVFR at times in showers. 14 && .MARINE...High pressure will weaken over the coastal waters as a frontal system approaches the region. The front will move across the area waters on Wednesday, bringing breezy southerly winds to the Puget Sound waters. Latest probabilistic guidance shows a 70-90 percent chance of gusts exceeding 22 kt starting late Wednesday morning. Westerly winds will also increase along the central and eastern Strait of Juan de Fuca as well on Wednesday, generally persisting at 20-30 kt. Breezy winds will persist through the afternoon hours before gradually subsiding in the evening. High pressure will then briefly build back over the coastal waters Thursday into Friday before additional frontal systems move across the area waters over the weekend. Seas across the coastal waters this afternoon have been hovering around 3 to 5 feet and will continue to persist within this range over the next several days, before increasing towards 4-6 feet again over the weekend. 14 && .SEW WATCHES/WARNINGS/ADVISORIES... WA...None. PZ...Small Craft Advisory from 5 AM to 11 PM PDT Wednesday for Central U.S. Waters Strait Of Juan De Fuca-East Entrance U.S. Waters Strait Of Juan De Fuca. Small Craft Advisory from 8 AM to 9 PM PDT Wednesday for Admiralty Inlet-Puget Sound and Hood Canal. && $$