000 FXUS66 KSEW 290301 RRA AFDSEW Area Forecast Discussion National Weather Service Seattle WA 801 PM PDT Thu Mar 28 2024 .SYNOPSIS...Low pressure spinning offshore will maintain scattered showers and isolated thunderstorm activity through the remainder of the day. The low will gradually sink southward towards northern California on Friday, allowing for showers to gradually taper across the area. Warmer and drier conditions are expected over the weekend and into next week as upper level ridging builds into the region. A return to cooler and wetter conditions looks to resume near midweek. && .SHORT TERM /TONIGHT THROUGH SUNDAY/...Scattered showers continue to rotate onshore across Western Washington as upper level low spins offshore. With loss of daytime heating, isolated thunderstorm threat has diminished for the remainder of the night. Recent satellite imagery shows subtle signs that the center of the low is beginning to retrograde offshore before it begins to shift southward on Friday and eventually merge with another upper low approaching north/central California. Shower activity will wind down by Friday morning and we'll likely start to see some clearing by late afternoon. We're still on track for 3 or 4 days of dry weather with temperatures climbing to above normal Sunday through Tuesday. No forecast updates anticipated this evening. Previous discussion follows with updates to marine/aviation portions. 27 Latest radar shows the heaviest scattered shower activity and some isolated thunderstorm activity moving along the coast this afternoon. Expect shower activity to continue area-wide through the remainder of the day today as a vertically stacked low pressure system continues to spin offshore and eject shortwave perturbations across the region. The main hazards with any thunderstorms that do develop are small hail/graupel, gusty winds, brief heavy downpours, and cloud-to- ground lightning. Expect overall rainfall amounts for the interior (outside of any heavier shower and thunderstorm activity) to remain rather light, with most places receiving a tenth to a quarter of an inch of rain through Friday morning. Areas along the coast and Olympics will be wetter - and look to receive a few tenths to 1.25 inches of rain. With snow levels generally hovering between 3000-3500 feet today, can expect another inch of snow for the Cascade passes through this evening. Scattered shower and isolated thunderstorm activity will wane Friday as a stronger shortwave trough moves into the eastern Pacific, prompts cyclogenesis of a new low, and pulls the current one offshore further southward towards northern California. Expect shower activity to mainly become confined to the coast and mountains by Friday afternoon and evening. Friday will be the start of a warm up across the region, with temperatures increasing a few degrees and topping out in the mid to upper 50s. An upper level ridge will then build into the Pacific Northwest over the weekend while the aforementioned low continues to move southward towards southern California and become cut off. This upper ridging will bring warmer and drier conditions to the region, with highs expected to increase a few degrees daily- and looking to top out in the upper 50s to low 60s by Sunday. .LONG TERM /MONDAY THROUGH THURSDAY/...Warm and dry weather will continue into Monday as upper level ridging remains situated across the Pacific Northwest and a cutoff low resides across southern California. Temperatures on Monday look to climb into the mid 60s for areas across the interior. The ridge then looks to dampen somewhat heading into Tuesday and Wednesday as upper level troughing redevelops over the northeastern Pacific and moves into British Columbia. At the surface, a cold front looks likely to move across the region around midweek, bringing the return of wetter and closer- to-normal temperatures. 14 && .AVIATION...Southwest flow aloft as an upper-low continues to spin offshore. Mostly MVFR this evening aside from brief instances of MVFR cigs/vis under heavier showers. Again, mostly VFR for tonight but can't rule out patchy MVFR (or IFR) conditions, especially for locations such as KPWT and KHQM. S to SW winds 8-12 kt throughout the interior with gusts up to 20-25 kt possible. SE winds around the same magnitude are in the forecast up at KBLI. Widespread VFR criteria looks to rebound on Friday. KSEA...VFR will likely persist, with brief drops to MVFR-IFR possible at times throughout the evening under heavier precipitation. S/SW winds 6 to 12 kt, with gusts up to 20 kts possible before diminishing into early Friday morning. More VFR conditions are expected into Friday. 33/McMillian && .MARINE...A surface low remains offshore with breezy winds felt throughout area waters. Small craft advisories will remain in place for the East Entrance of the strait, Admiralty Inlet, and the Northern Inland Waters, and coastal waters. These headlines will persist into Friday, before the surface low drifts away from the area, which will let winds relax this weekend. With high pressure building overhead around this time, relatively benign conditions are expected into next week. Seas look to drop below 10 feet Friday morning, and continue to lower to around 3 to 6 ft this weekend. 33/McMillian && .HYDROLOGY...No river flooding is forecast over the next 7 days. && .SEW WATCHES/WARNINGS/ADVISORIES... WA...None. PZ...Small Craft Advisory until 11 AM PDT Friday for Grays Harbor Bar. Small Craft Advisory until 5 AM PDT Friday for West Entrance U.S. Waters Strait Of Juan De Fuca. Gale Warning until 5 PM PDT this afternoon for Coastal Waters From Cape Flattery To James Island 10 To 60 Nm-Coastal Waters From Cape Flattery To James Island Out 10 Nm-Coastal Waters From James Island To Point Grenville 10 To 60 Nm- Coastal Waters From James Island To Point Grenville Out 10 Nm-Coastal Waters From Point Grenville To Cape Shoalwater 10 To 60 Nm-Coastal Waters From Point Grenville To Cape Shoalwater Out 10 Nm-East Entrance U.S. Waters Strait Of Juan De Fuca. Small Craft Advisory from 5 PM this afternoon to 8 AM PDT Friday for East Entrance U.S. Waters Strait Of Juan De Fuca. Small Craft Advisory until 8 AM PDT Friday for Admiralty Inlet- Northern Inland Waters Including The San Juan Islands. Small Craft Advisory from 5 PM this afternoon to 11 AM PDT Friday for Coastal Waters From Cape Flattery To James Island 10 To 60 Nm-Coastal Waters From Cape Flattery To James Island Out 10 Nm-Coastal Waters From James Island To Point Grenville 10 To 60 Nm-Coastal Waters From James Island To Point Grenville Out 10 Nm-Coastal Waters From Point Grenville To Cape Shoalwater 10 To 60 Nm-Coastal Waters From Point Grenville To Cape Shoalwater Out 10 Nm. && $$