Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA
Issued by NWS Seattle/Tacoma, WA
818 FXUS66 KSEW 251622 AFDSEW Area Forecast Discussion National Weather Service Seattle WA 922 AM PDT Tue Jun 25 2024 .SYNOPSIS...High pressure aloft continues to build over the region, maintaining warmer and dry conditions through Tuesday. The next upper trough crosses the area Wednesday and Thursday bringing a return of showers and cooler temperatures. Expect a similar pattern late in the week with a brief warm up alternating with weak passing disturbances. && .SHORT TERM /TODAY THROUGH THURSDAY/...Mostly clear skies with high pressure building over the Pacific Northwest today. Temperature already off a mild start across the interior and expect afternoon temperatures to reach the upper 70s to around 80 in the interior, while coastal temperatures largely remain in the 60s a sea breeze arrives to halt the warm up. Remainder of previous short/long term sections remain unchanged and follow. Wednesday will be cooler and cloudier as the ridge pushes east and a trough moves in from the west. Temperatures on Wednesday will be in the 60s to lower 70s - close to average. We`ll also see showers with the trough and the coast may see 0.25" or so through the day. Post- frontal onshore flow increases Wednesday night with a convergence zone setting up over Snohomish and King counties. There is also a slight chance of thunderstorms in the North Cascades where instability is the greatest. The trough moves east of the Cascades on Thursday but we`re still under moderate onshore flow with more cool and wet weather (especially in the interior and Cascades). Temperatures will dip again with highs only in the 60s. 33 .LONG TERM /FRIDAY THROUGH MONDAY/...High pressure rebuilds over the region Friday and Saturday for a return of dry and mild weather (temps closer to average). West to SW flow returns Saturday night and Sunday with another trough over the West. There`s not as much moisture attached to this system (compared to Wednesday-Thursday) but we should still see measurable rain across most areas. Moving forward, we`re stuck in zonal, onshore flow, into early next week. There`s a chance of showers along the coast and in the mountains with near normal temperatures. 33 && .AVIATION...Flow aloft turning more south/southwesterly this morning as weak upper ridging builds over W WA. Satellite showing just a few mid to high level clouds streaming overhead along the northern coast and areas north of KPAE. Conditions primarily VFR across the area terminals this morning and expect these conditions to dominate throughout the rest of the day as high pressure builds over the region. N/NE surface winds generally around 5 to 10 knots, turning more northwesterly by this afternoon. KSEA...VFR conditions will continue throughout the remainder of the day. North winds 7 to 12 knots this morning will gradually ease into the afternoon and turn northwesterly, around 4 to 8 knots. Winds will then become light overnight and transition back to the S/SW between 12-14Z Tuesday. Maz/Borth && .MARINE...High pressure situated offshore will help influence lower pressure inland, with relative onshore flow throughout the next several days. Diurnal pushes through the Strait of Juan De Fuca are possible each of the days that could result in Small Craft Advisories at times, with general benign conditions over the coastal waters. A frontal system will push through the area waters on Wednesday, with elevated southerly winds, but latest guidance shows winds to be under any criteria thresholds for now. Coastal seas this morning have been hovering around 4 to 6 feet and generally will maintain this height through midweek and into the weekend. Maz && .SEW WATCHES/WARNINGS/ADVISORIES... WA...None. PZ...None. && $$