![National Oceanic and Atmospheric Administration](/build/images/header/noaa.d87e0251.png)
![National Weather Service](/build/images/header/nws.4e6585d8.png)
![United States Department of Commerce](/build/images/header/doc.b38ba91a.png)
Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA
Issued by NWS Seattle/Tacoma, WA
117 FXUS66 KSEW 132206 AFDSEW Area Forecast Discussion National Weather Service Seattle WA 306 PM PDT Tue Aug 13 2024 .SYNOPSIS...Mostly cloudy and cooler than normal, with isolated showers and possibly thunderstorms in the North Cascades near the crest this afternoon and evening. Morning clouds, with afternoon sunshine and near normal temperatures Wednesday and Thursday. The pattern looks to trend wetter into the weekend with what amounts to a good chance of widespread precipitation for much of the region. && .SHORT TERM /TONIGHT THROUGH FRIDAY/...Cool and cloudy weather continues today with an upper level troughing over the region. There remains a chance of isolated showers and around a 15% probability of thunderstorms along the crest of the North Cascades. The thicker stratus layer over the area has been making it pretty tough for sunbreaks this afternoon, while it is possible that few locations may see a little sun late this afternoon - most locations are likely to remain cloudy through the evening. The weak upper level trough exits east on Wednesday, allowing heights will build through the day. Morning clouds are expected to scatter out for many locations in the early afternoon as onshore flow eases. More sunshine will help afternoon temps rise to near normal levels - into the mid to upper 70s in the interior and mid to high 60s along the coast. Thursday will see pretty similar conditions - morning clouds with afternoon clearing and near normal temperatures. A weak upper level trough moving to the south may help boost showers again over the higher terrain - with a 15 to 20% chance of thunderstorms along the crest of the Cascades Thursday afternoon and evening. Friday looks to be a transitional day as a system approaches the area from the northwest. This will likely result in a bit more marine stratus Friday morning with a later break out for many areas, except the coast which will likely remain mostly cloudy. Temperatures will remain just below normal and there is another chance of showers over the mountains as well as isolated Thunderstorms. .LONG TERM /SATURDAY THROUGH TUESDAY/...The grand ensemble - including the EPS, GEFS and GEPS systems has been consistently showing the offshore upper level low lingering over the NE Pacific through much of the weekend. The overall effect will be cooler and more significantly, wetter conditions through the weekend. There are very good chances of widespread prectipitation affecting the area. By Sunday afternoon there is a 75% of at least widespread light rain over all of Western Washingtion, with lower probabilities for heavier amounts particularly over the higher terrain. In addition there is some chance of thunderstorms in the area as well. At the very least this does look like the most widespread rain for the region in some time. && AVIATION...Light, variable flow aloft will continue into tonight with an upper trough moving east of the area. Widespread VFR cigs continue this afternoon with areas of MVFR lingering, primarily along the coast. VFR will continue into early tonight for the interior with LIFR/IFR cigs developing along the coast. Cigs will likely lower towards MVFR for portions of Puget Sound Wednesday morning, with clearing expected by late morning. Lower vsbys expected along the coast. W/SW winds will continue for most into this evening before becoming light tonight. KSEA...VFR cigs with mid-level clouds. VFR continue into early tonight. Cigs are expected to lower towards MVFR, with the highest probabilities of MVFR (around 30%) between 12-18z. Southwest winds between 6 to 10 kts this afternoon are expected to transition more N/NW tonight, before becoming SW Wednesday morning. JD && .MARINE...Onshore flow will continue for the majority of this week across the area waters. Diurnally driven pushes are expected through the Strait of Juan de Fuca each evening. The best potential, over the next few days, of SCA winds through the Strait of Juan de Fuca is Thursday evening. Otherwise, lower visibilities may be possible tonight along the inner Coastal Waters as well as the Strait of Juan de Fuca. Seas will remain 2 to 4 feet through Thursday and briefly build to 5 to 6 feet along the outer Coastal Waters on Friday. JD && .SEW WATCHES/WARNINGS/ADVISORIES... WA...None. PZ...None. && $$