FXUS66 KOTX 192115 AFDOTX Area Forecast Discussion National Weather Service Spokane WA 215 PM PDT Fri Jul 19 2024 .SYNOPSIS... Strong high pressure will continue to amplify, bringing increasing heat that will peak on Sunday, with widespread temperatures in the 100s and some areas reaching 110 or higher. A weather system will bring lower temperatures beginning next Tuesday, but will also bring increased winds, which, combined with dry weather, will bring increased fire risk. .DISCUSSION… Today through Sunday Night: Excessive heat continues to b e of major concern, as temperatures will continue to increase past already dangerous levels. Models are in good agreement that a strong upper-level ridge will build into the area on Saturday and remain potent on Sunday, with the ridge axis stalled over the area during the weekend before slowly beginning to shift east into Monday. Initial warming will be due to subsidence from the ridge, but upper-level flow will become southerly on the back side of the ridge as it shifts east, with 850mb temperatures forecast to reach as high as 32C on Sunday. The HRRR does show smoke from Oregon drifting northward, which could abate temperatures slightly, but with little-to-no forecast cloud cover through the weekend, surface heating will be extreme. Heat Advisories are currently in effect through 11 am PDT Saturday, with Excessive Heat Warnings in effect from 11 am PDT Saturday through 8 PM PDT Monday. Vulnerable populations should plan well in advance to find cooling, and animals should be brought indoors if possible or given water, shade, and fans otherwise. Monday through Thursday: On Monday, the 300mb low will continue to strengthen in the Gulf of Alaska and reach farther south, bringing west-to-southwest flow that will bring an embedded shortwave into the region and allow the ridge to begin to break down, bringing a bit lower surface temperatures but increasing wind, especially central WA. Increasing winds in combination with extremely dry air will be of concern for any existing fires. Forecast CAPE (100-200 J/kg), positive vorticity advection (lift), 200-850mb shear, and elevated moisture raises concern for high- based thunderstorms capable of dry lightning Monday. Models indicate dry and breezy conditions will continue through next week despite cooler temperatures Tuesday onward with high temperatures in the upper 80s to mid 90s. Increased surface winds in combination with continued extremely dry air will create multiple days of elevated to critical fire weather conditions, which will be closely monitored in the coming days. /Cooke && .AVIATION... 18Z TAFS: A building upper level ridge will allow VFR conditions to continue through the period. The only exception will be some hazy conditions from smoke near wildfires that may reduce visibilities along Lake Chelan, and the Methow Valley. FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: With the exception of smoke near wildfires confidence is high for continued VFR conditions. ----------------------- 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 64 101 67 106 70 102 / 0 0 0 0 0 0 Coeur d'Alene 62 99 66 103 69 102 / 0 0 0 0 0 0 Pullman 59 97 63 102 63 98 / 0 0 0 0 0 0 Lewiston 71 107 72 112 75 107 / 0 0 0 0 0 0 Colville 53 99 56 104 60 101 / 0 0 0 0 0 0 Sandpoint 57 96 62 101 64 100 / 0 0 0 0 0 0 Kellogg 68 97 71 99 73 101 / 0 0 0 0 0 0 Moses Lake 61 102 65 109 68 102 / 0 0 0 0 10 10 Wenatchee 69 102 74 107 75 103 / 0 0 0 0 0 0 Omak 64 104 68 110 74 108 / 0 0 0 0 0 0 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...Heat Advisory until 11 AM PDT Saturday for Central Panhandle Mountains-Coeur d'Alene Area-Idaho Palouse-Lewis and Southern Nez Perce Counties-Lewiston Area-Northern Panhandle. Excessive Heat Warning from 11 AM Saturday to 8 PM PDT Monday for Central Panhandle Mountains-Coeur d'Alene Area-Idaho Palouse-Lewis and Southern Nez Perce Counties-Lewiston Area- Northern Panhandle. WA...Heat Advisory until 11 AM PDT Saturday 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. Excessive Heat Warning from 11 AM Saturday to 8 PM PDT Monday 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. Fire Weather Watch from Sunday afternoon through Sunday evening 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)-Foothills of Central Washington Cascades (Zone 705)-Methow Valley (Zone 704). Heat Advisory from 11 AM Saturday to 8 PM PDT Monday for Western Chelan County. && $$