FXUS66 KSEW 131927 AFDSEW Area Forecast Discussion National Weather Service Seattle WA 1227 PM PDT Mon Apr 13 2026 .SYNOPSIS... Showers will continue through tonight. The next weather system will move into the area on Tuesday, bringing lowland rain, mountain snow, and breezy winds to western Washington. Precipitation will linger into Wednesday, with drier weather expected Thursday into the weekend. Cold, near-freezing morning lows are expected for portions of the south Sound and Chehalis Valley on Thursday. Chances of precipitation return late in the weekend into early next week. && .SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/... Showery and unsettled conditions will continue through the remainder of the day today. Cloudy conditions and afternoon highs will generally be in the low to mid 50s across the area. The next system will then move into the area on Tuesday, bringing the next round of lowland rain, mountain snow, and breezy winds. Mountain snow will continue into Wednesday and isolated chances of thunderstorms will be possible in the wake of the system. Additional details on the hazards have been outlined below: Winds: Southerly winds will increase across western Washington through the morning hours on Tuesday. Wind gusts will generally be between 25-40 mph, though isolated gusts to 45 mph will be possible at times. With new foliage on trees, tree damage may be possible with any gusts between 35-45 mph. Winds will gradually ease area-wide again late Tuesday night into Wednesday morning. Mountain Snow: Snow levels will start out between 3000-4000 ft on Tuesday, but will fall to 1000-1500 ft by Wednesday, bringing accumulating snow for the mountains- especially for the Cascade passes. The heaviest snow will occur Tuesday night into Wednesday morning and will be for elevations generally above 2500 ft. Snow will linger through the day Wednesday, before tapering late Wednesday night into Thursday. Rain: This system will bring the next round of lowland rain to the region. The most likely rainfall amounts for the interior lowlands look to be between 0.50-1 inch, with the typical shadowed areas generally expected to see a little less- between 0.25-0.50 inches. Areas along the coast will see the most rain, with rainfall amounts generally expected to range between 1-1.25 inches from Tuesday morning through Wednesday night. Thunderstorms: A slight chance of thunderstorms will be possible in the cool post-frontal airmass on Wednesday. The most likely areas for any thunderstorm development will be along the Pacific Coast. Any isolated thunderstorms that do develop may produce dangerous lightning, gusty winds, small hail, and brief heavy downpours. && .LONG TERM /THURSDAY THROUGH MONDAY/... Drier conditions are expected the second half of the week with high pressure building back into the region. Clearing skies overnight will allow for temperatures to dip into the low to mid 30s across much of the area by Thursday morning. Most likely spots to approach freezing will be areas around the south Sound and the Chehalis Valley- where frost will also be possible. Dry conditions will persist through Saturday as the ridge of high pressure moves overhead. Afternoon high temperatures will warm a few degrees each day- topping out in the upper 50s to low 60s across the region by Saturday. An upper level low will then approach the region on Sunday, bringing the return of shower chances to the region. Showers then look to linger into early next week. 14 && .AVIATION... Northwest flow becoming westerly tonight into Tuesday as an upper- low tracks along the BC coast. Mostly VFR so far this afternoon but, MVFR to IFR cigs remain for terminals (KBFI and KPAE) impacted by a PSCZ. Guidance also suggests mostly VFR this evening with the exception of KPAE (IFR/LIFR) where a convergence zone will continue to meander. A stout cold front will arrive at the coast around 14- 16z Tuesday and inland 16-18z. Here MVFR and IFR cigs will become more widespread along with gusty winds. 25 to 30 kt gusts are forecast Tuesday afternoon into the evening. KSEA...Low-end VFR cigs this afternoon as a convergence zone meanders just north of the terminal. Breezy SSW winds will produce gusts up to 20 kt before gradually decreasing after 00z. SSW are forecast to increase again Tuesday morning as a cold front enters. Gusts up to 30 kt are likely during the afternoon and early evening. As the front arrives, low ceilings are to accompany it as MVFR conditions manifest as well. 41 && .MARINE... Surface high pressure resides well offshore in the NE PAC. Onshore flow continues over the area waters as well for the small craft advisory in the Strait of Juan De Fuca for enhanced westerlies. A stronger frontal system is still on track to enter the area late tonight into Wednesday morning for breezy conditions and elevated seas. A small craft advisory remains in effect for all of the coastal water zones starting early Tuesday as S/SW winds increase ahead of the front. New SCAs have also been added for the inland water zones of Puget Sound, Admiralty Inlet, and the Northern Inland waters. Can't rule out the brief the potential for gale strength gusts, particularly in the strait. Coastal seas 4 to 6 ft tonight before increasing upward to 9 to 12 feet on Tuesday evening. Seas 8 to 10 ft through Thursday before decreasing by Friday to 3 to 5 feet. 41 && .HYDROLOGY... With rain moving into the area Tuesday into Wednesday, slight rises on area rivers will be possible. The Skokomish River is expected to rise into Action Stage with the additional precipitation. Snow levels will fall mid week to 1000-1500 ft, but no river flooding is expected at this time. 14 && .SEW WATCHES/WARNINGS/ADVISORIES... WA...Winter Storm Warning from 11 AM Tuesday to 11 PM PDT Wednesday for Cascades of Pierce and Lewis Counties-Cascades of Snohomish and Northern King Counties-Cascades of Southern King County-Cascades of Whatcom and Skagit Counties. PZ...Small Craft Advisory until 5 AM PDT Tuesday for Central U.S. Waters Strait Of Juan De Fuca-East Entrance U.S. Waters Strait Of Juan De Fuca. Small Craft Advisory from 5 AM Tuesday to 5 AM PDT Wednesday 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. && $$