FXUS66 KOTX 220003 AFDOTX Area Forecast Discussion National Weather Service Spokane WA 503 PM PDT Fri Aug 21 2026 .KEY MESSAGES... - A Heat Advisory has been issued through Friday evening due to very warm temperatures and widespread Major HeatRisk. - Saturday system brings increased chances for showers, thunderstorms, and gusty winds. This will lead to critical fire weather conditions across the Inland Northwest. - Patchy blowing dust is possible Saturday in the Western Columbia Basin. && .SYNOPSIS... Temperatures will be very warm Friday with widespread Major HeatRisk. A pattern change Friday night into Saturday will bring unsettled conditions with chances for showers, thunderstorms, and gusty winds. Sunday will remain breezy and dry, but cooler. Temperatures will warm again at the start of next week with breezy conditions returning by the middle of next week. && .DISCUSSION... Friday through Sunday: An incoming cold front will bring gusty winds and isolated to scattered thunderstorms to the region Saturday into Sunday. Today, ahead of the cold front passage on Saturday, temperatures have warmed into the high 90s with triple digits possible in the lower Basin. This has led to widespread Major HeatRisk values, so anyone without adequate cooling and hydration as well as health systems and industries could see impacts. A Heat Advisory is valid through much of the Inland Northwest through 10 PM this evening and low temperatures into tomorrow will be in the 60s and 70s and provide little overnight relief. Tonight into Saturday, moisture advection ahead of the frontal passage will raise PWATs to 125 to 150 percent of normal, around 0.75 to 1 inch. The arrival of the cold front on Saturday accompanied by a 40-50kt 500mb jet and warm overnight and daytime temperatures will create a favorable environment for isolated to scattered thunderstorms across the Cascades and northern mountains. While these showers will initially start out as isolated in nature, as daytime warming increases, thunderstorms become more scattered in nature, especially into Saturday afternoon and evening. With PWATs near 1 inch and DCAPE values 500 J/kg and higher, main impacts look to be isolated heavy rainfall rates, gusty outflow winds up to 50 mph, and lightning induced fire starts. Steep terrain and burn scars will need to be monitored for any heavy rainfall rates. This threat will move eastward across the forecast area through the day, and Saturday night into Sunday morning the ID Panhandle sees isolated to scattered thunderstorms. To reflect these critical fire weather conditions, Red Flag Warnings have been issued. For the Cascades and northern mountains, the Red Flag Warning is valid from Saturday morning through Sunday morning. For the ID Panhandle, the Red Flag Warning is valid from Saturday afternoon through Sunday morning. Another impact from this cold front will be gusty winds leading to critical fire weather concerns across the Basin and Spokane area. There is a 40 percent chance and higher for most locations in the region to see wind gusts higher than 30 mph on Saturday night. Areas that will see the highest gusts include the Lewiston, Moses Lake, Wenatchee, and Waterville Plateau areas. A Red Flag Warning for the basin, Palouse, and Spokane areas is valid from Saturday afternoon through Saturday evening. Potential impacts from these winds include rapid spreading of wildfires alongside blowing objects and difficulties driving, especially for high profile vehicles. While models initially had the low moving out of the area quicker, there is now better agreement that the low lingers over the state of Washington through Sunday before moving out of the area Sunday night into Monday. Impacts will continue to be seen into Sunday afternoon with residual winds and isolated to scattered thunderstorms in the northern Idaho Panhandle. One thing to keep a close eye on is the extent of the thunderstorms post cold frontal passage on Sunday morning. As high-res models pick up the end of the event Sunday morning, they are showing enough lingering instability throughout fire zone 708 (Eastern Columbia Basin/Palouse/Spokane area) that it may need to be added into the Red Flag Warning. Wind gusts around 15- 20 mph will linger throughout the Cascade gaps, Okanogan Valley, Waterville Plateau, Columbia Basin, Spokane/CdA, and Palouse areas through late Sunday afternoon, bringing continued elevated fire weather conditions. A significant cooldown due to the cold front will be observed Saturday into Sunday, with high temperatures dropping around ten or more degrees. Temperatures will end up being a couple degrees below normal on Sunday. Apart from the northern mountains and Cascades, precipitation chances drop down to near zero. Monday through Wednesday: With high confidence (80 percent of clusters) indicating a strengthening ridge building over the area early next week, the temperature drop will be short lived. By Tuesday, temperatures will again warm into the high 80s to low 90s. Clusters show a 50 percent chance of another trough approaching the PNW coast, though timing and track are uncertain. This could lead to a return of gusty winds and thunderstorm chances. Overall chances for precipitation remain low, with PoPs 15 percent and lower expected Monday through Wednesday. /AS && .AVIATION... 00Z TAFs: VFR conditions are expected to continue through the TAF period except KEAT. There will be elevated showers that move through the region late this evening and overnight. There is a small chance (10-15% chance) of sprinkles) from 06-15Z for most TAF sites as a vort max moves through. Chance of TS out of these is very low (5%) but cannot be ruled out. Bands of convection will form in the Cascades in the very late morning to early afternoon and eventually SE WA and southern ID Panhandle around 23-00z. Confidence is too low for TS in the TAF but there is a 10-20% chance around 00z for KLWS-KPUW-KEAT. Vsbys at KEAT will degrade this evening around 07-08z as northwest winds bring in smoke from the Little Giant Fire. South to southwest winds will increase in the Columbia Basin, Palouse, and Spokane area in the late morning to early afternoon. FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: Low confidence for TS impacts before 0Z for KEAT-KLWS-KPUW. ----------------------- 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:/www.weather.gov/otx/avndashboard && .Preliminary Point Temps/PoPs... Spokane 68 94 59 82 54 87 / 10 10 20 0 0 0 Coeur d'Alene 68 95 60 81 53 86 / 10 10 40 0 0 0 Pullman 62 91 51 78 46 86 / 10 10 30 0 0 0 Lewiston 72 98 62 87 59 92 / 10 10 40 0 0 0 Colville 60 95 52 81 45 87 / 10 10 40 10 0 0 Sandpoint 62 93 56 77 47 83 / 10 20 40 10 0 0 Kellogg 63 92 55 77 52 84 / 10 10 40 0 0 0 Moses Lake 69 95 56 85 54 89 / 10 10 0 0 0 0 Wenatchee 76 94 63 83 62 88 / 20 20 0 0 0 0 Omak 71 96 56 85 56 88 / 10 20 20 10 0 0 && .OTX WATCHES/WARNINGS/ADVISORIES... WA...Heat Advisory until 10 PM PDT this evening for Central Chelan County-Lower Garfield and Asotin Counties-Moses Lake Area- Northeast Blue Mountains-Northeast Mountains-Okanogan Highlands-Okanogan Valley-Spokane Area-Upper Columbia Basin-Washington Palouse-Waterville Plateau-Wenatchee Area-Western Okanogan County. Red Flag Warning from 4 PM Saturday to 11 AM PDT Sunday for Selkirk Mountains of Northeast Washington (Zone 700). Red Flag Warning from noon to 10 PM PDT Saturday for Colville Reservation (Zone 702)-Eastern Columbia Basin -Palouse - Spokane Area (Zone 708)-Foothills of Central Washington Cascades (Zone 705)-Foothills of Northeast Washington (Zone 701)-Lower Palouse -Snake River (Zone 709)- Waterville Plateau (Zone 706)-Western Columbia Basin (Zone 707). Air Quality Alert until 2 PM PDT Monday for Central Chelan County-Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-Waterville Plateau-Wenatchee Area-Western Chelan County-Western Okanogan County. Red Flag Warning from 11 AM Saturday to 8 AM PDT Sunday for East Portion of North Cascades National Park/Lake Chelan National Recreation Area (Zone 697)-East Washington Central Cascades (Zone 696)-East Washington North Cascades (Zone 698)-Methow Valley (Zone 704)-Okanogan Highlands and Kettle Mountains (Zone 699)-Okanogan Valley (Zone 703). ID...Heat Advisory until 10 PM PDT this evening for Central Panhandle Mountains-Coeur d'Alene Area-Idaho Palouse- Lewis and Southern Nez Perce Counties-Lewiston Area- Northern Panhandle. Red Flag Warning from 4 PM Saturday to 11 AM PDT Sunday for Northern and Central Idaho Panhandle (Zone 101). && $$