739 FXUS66 KOTX 252130 AFDOTX Area Forecast Discussion National Weather Service Spokane WA 230 PM PDT Thu Sep 25 2025 .KEY MESSAGES... - Vigorous dry cold front passage Thursday afternoon/evening with windy and dry conditions resulting in critical fire weather conditions. - Winds may also produce blowing dust across the Waterville Plateau into the Columbia Basin Thursday afternoon. - Patchy frost for northern mountain valleys and northern Panhandle overnight Thursday and Friday. && .SYNOPSIS... Windy conditions and very low RHs are expected with a cold front passage late Thursday afternoon and evening. The combination of gusty winds and dry conditions will lead to critical fire weather conditions across much of central and eastern Washington. Chilly mornings Friday and Saturday before temperatures see a bump up above normal over the weekend. Cooler temperatures and chances for showers by early next week. && .DISCUSSION... ...BREEZY TO WINDY CONDITIONS THURSDAY AFTERNOON AND EVENING WITH A ROBUST COLD FRONT PASSAGE... Thursday: A fast-moving cold front and associated trough is pushing into western Washington early this afternoon and will continue swiftly east through the Inland Northwest later this afternoon and evening. This system will bring dry and gusty westerly winds. Ahead of the front, southwest winds are already increasing with relative humidity values in the low teens across central Washington. The strongest winds are expected in the lee of the Cascades as the front moves through with winds decreasing though remaining gusty across the Columbia Basin, and extending into the Spokane area and Palouse. As of 12 PM, the PDX-GEG pressure gradient was +8 mb, with values projected to rise to +11-12 mb. This will support sustained winds of 15-30 mph with gusts of 30-45 mph late this afternoon into the evening. A few light showers (15% chance) will be possible over the northern mountains with the frontal passage, but otherwise this will be a dry front with PWATs dropping to 0.30-0.40 inches as much drier air aloft mixes to the surface. The main impacts will be rapid fire spread potential with any new starts and areas of blowing dust near recently plowed fields. A secondary concern will develop this evening into the early overnight hours across the Cascades and east slopes as a northwest- to- southeast oriented jet streak shifts into Washington behind the upper trough. Strong westerly flow over the terrain combined with a stable layer near ridge tops will favor mountain wave activity. While an overnight surface inversion will keep lower valley winds lighter, exposed ridges may experience continued gusty winds from these trapped waves. Friday through Wednesday: Broad zonal flow will set up across the Pacific Northwest on Friday following the cold frontal passage. Dry air and clearing skies Thursday night into Friday will allow for a chilly start Friday morning, with afternoon highs 5-10 degrees cooler than Thursday (upper 60s to mid-70s). Over the weekend, the Inland Northwest will sit on the western side of an amplifying ridge over the central US in response to a deepening trough over the eastern Pacific and a low moving into the Gulf of Alaska. Temperatures will rebound into the upper 70s to 80s through Sunday. From Sunday night into midweek, ensemble guidance is in general agreement that the leading upper-level trough will move onshore the PNW, followed by a weaker version of the Gulf of Alaska low. Forecast confidence is high that temperatures will cool with increasing precipitation chances across the Inland Northwest. Between 5 AM Monday and 5 AM Thursday, there is a >70% chance of at least 0.25 inches of precipitation across the Cascades, northern mountains, Idaho Panhandle mountains, and Camas Prairie. Probabilities are 50- 70% for the northern Washington and Idaho Panhandle valleys, Spokane area, Palouse, and L-C Valley, decreasing to 15-30% over the Columbia Basin, Waterville Plateau, and near Wenatchee. For the larch marchers, NBM guidance also supports snow levels lowering to 6500-7000 feet over the Cascades Monday night through Wednesday, which could bring snow to the higher peaks. Stay tuned! /vmt && .AVIATION... 18Z TAFS: A strong cold front will approach today bringing increased west to southwest winds, shifting to northwest behind the front in central and northeast Washington during the late afternoon and evening. Wind gusts of 20-30 kts are forecast across the region during the afternoon and evening. Strong westerly winds aloft over the Cascades will favor mountain wave development through the evening, potentially leading to gusty winds up to 45kts over the east slopes of the Cascades. Winds have cleared up visibilities around KEAT. Nearby fires are expected to become more active today and KEAT/KEPH/KMWH could see visibility lower again but to what degree carries low confidence. The winds will also kick up areas of blowing dust across the Columbia Basin. West winds could lead to reduced visibility at KMWH/KGEG/KSFF this afternoon from a combination of wildfire smoke and blowing dust. Otherwise skies are expected to be clear for most of today, before a band of passing mid and high clouds with the front. FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: Wildfire smoke from fires in Cascades pushing east as well as areas of blowing dust this afternoon leads to low to moderate confidence of the visibility forecast for KEAT/KMWH/KGEG. There is higher confidence in VFR conditions through the TAF period at KSFF, KCOE, KPUW, KLWS. There is low confidence in wind gusts up to 45kts in the lee of the Cascades. ----------------------- Confidence descriptors: Low - Less than a 30 percent chance Moderate - 30 to 70 percent chance High - Greater than a 70 percent chance For additional probabilistic information for NWS Spokane airports, please refer to the Aviation Dashboard on our webpage: https:/weather.gov/otx/avndashboard && .Preliminary Point Temps/PoPs... Spokane 44 69 46 76 50 82 / 0 0 0 0 0 0 Coeur d'Alene 45 69 45 75 50 82 / 0 0 0 0 0 0 Pullman 41 66 42 76 48 79 / 0 0 0 0 0 0 Lewiston 51 72 49 81 54 84 / 0 0 0 0 0 0 Colville 35 71 37 73 38 78 / 10 0 0 0 0 0 Sandpoint 41 67 40 71 45 78 / 10 0 0 0 0 0 Kellogg 46 66 47 77 55 81 / 0 0 0 0 0 0 Moses Lake 42 73 45 77 46 79 / 10 0 0 0 0 0 Wenatchee 51 74 54 77 55 78 / 10 0 0 0 0 0 Omak 43 73 50 76 50 78 / 10 0 0 0 0 0 && .OTX WATCHES/WARNINGS/ADVISORIES... WA...Red Flag Warning until 11 PM PDT this evening for Colville Reservation (Zone 702)-East Portion of North Cascades National Park/Lake Chelan National Recreation Area (Zone 697)-East Washington North Cascades (Zone 698)-Eastern Columbia Basin -Palouse -Spokane Area (Zone 708)- Foothills of Central Washington Cascades (Zone 705)-Lower Palouse -Snake River (Zone 709)-Methow Valley (Zone 704)- Okanogan Valley (Zone 703)-Waterville Plateau (Zone 706)- Western Columbia Basin (Zone 707). Air Quality Alert until noon PDT Friday for Central Chelan County-Okanogan Highlands-Okanogan Valley-Waterville Plateau-Wenatchee Area-Western Chelan County-Western Okanogan County. Red Flag Warning until 9 AM PDT Friday for East Washington Central Cascades (Zone 696). ID...None. && $$