Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA
Issued by NWS Seattle/Tacoma, WA
194 FXUS66 KSEW 061544 AFDSEW Area Forecast Discussion National Weather Service Seattle WA 844 AM PDT Thu Jun 6 2024 .SYNOPSIS...Upper level ridge over Western Washington through Friday will shift into Eastern Washington Saturday. Weak upper level troughs will move through Sunday and Tuesday with an upper level ridge in between the troughs Monday. && .UPDATE...Pleasant morning across western Washington, with some thin high clouds drifting across the region. Temperatures today will reach the upper 60s to mid-70s this afternoon. The current forecast is on track and no updates are planned. -Wolcott- && .SHORT TERM /TODAY THROUGH SATURDAY/...Satellite imagery shows flat upper level ridge over Western Washington early this morning. Just some high clouds near the Canadian border at 2 am/09z. Temperatures were in the mid 40s to mid 50s. Flat upper level ridge remaining over Western Washington today. Southwesterly flow aloft will bring some high clouds over the area at times. Low level onshore flow will keep high temperatures near normal, in the upper 60s to mid 70s. Upper level ridge gaining amplitude tonight into Friday. Temperatures aloft warming with 850 mb temperatures rising from plus 8C to plus 11C tonight to plus 13C to plus 16C by late Friday afternoon. Low level flow remaining northwesterly onshore which will cap the warming from Thursday highs to the 5 to 10 degree range putting highs in the 70s to lower 80s. Lows tonight with mostly clear skies in the mid 40s to lower 50s. The cool overnight low temperatures will keep the HeatRisk in the minor category. Upper level ridge axis over Western Washington Friday night will shift into Eastern Washington Saturday. Increasing low level onshore flow during the day Saturday. Lows Saturday morning a few degrees warmer, in the lower to mid 50s. Increasing onshore flow will result in less daytime heating but with the warmer temperatures to start the day highs will end up being close to Friday`s highs, in the 70s and lower 80s. The exception to this will be along the coast where the increasing onshore flow will cool daytime highs back into the 60s and lower 70s. Little change in the HeatRisk for the interior. .LONG TERM /SUNDAY THROUGH WEDNESDAY/...Extended models in fairly good agreement with a weak upper level trough moving through Western Washington Sunday. Most of the moisture with the trough will be in the mid levels giving the area for some filtered sunshine. Main impact will be to increase the low level onshore flow Sunday resulting in cooler high temperatures for the interior, upper 60s to mid 70s. Highs along the coast in the lower to mid 60s. There is a chance of showers over the Cascades in the afternoon. Temporary weak upper level ridge crossing the area Monday will be followed by another weak with not very much moisture trough Tuesday. Both of these features will have little effect on the daytime highs with mid 60s to mid 70s for the interior and lower to mid 60s on the coast. Weak upper level trofiness remaining over the area Wednesday. Increasing low level onshore flow will drop daytime highs into the 60s and lower 70s. Felton && .AVIATION...West-southwest flow aloft becoming more westerly today with an upper ridging building into the area. Mostly clear skies through the TAF period with high clouds at times, especially this morning. Slight chance of low cigs along the coast, mainly north coast, along with with patchy fog in river valleys but should decrease as the morning progress. Light north winds this morning, increasing this afternoon. KSEA...VFR cigs with high clouds at times. NE winds generally 6 to 10 kts this morning, becoming more N/NW this afternoon. JD/McMillian && .MARINE...Northerly winds will continue through Friday, increasing in the afternoon and evening for the waters as high pressure builds. Winds are expected to remain below SCA threshold. Onshore flow will increase Saturday night into Sunday for potential westerly SCA winds through the Strait of Juan de Fuca. Onshore flow into next week. Seas will slowly subside below 10 feet this morning, and remain 5 to 8 feet into Saturday. Seas will then build Saturday night into Sunday, with seas potentially approaching 10 feet for the outer Coastal Waters late weekend. JD/McMillian && .SEW WATCHES/WARNINGS/ADVISORIES... WA...None. PZ...None. && $$