FXUS66 KOTX 191739 AFDOTX Area Forecast Discussion National Weather Service Spokane WA 939 AM PST Wed Feb 19 2025 .SYNOPSIS... An incoming weather system arrives today bringing widespread snow and rain. Warmer temperatures and rain arrive late in the week into next weekend as high temperatures warm into the 40s. This will result in melting snow across the lower elevations. Rain and snowmelt expected to lead to local hydro issues for low lying and poor drainage areas. && .DISCUSSION... Today through Thursday: The moisture associated with the incoming Low is beginning to press into the Inland Northwest. Ensembles have adjusted the track further North than previous runs. It is allowing slightly warmer temperatures into the low levels from previous runs and muting the cold air intrusion into North Washington and Idaho. It has also brought more moisture into the Methow Valley increasing expected snow amounts to 2-4 inches. The rest of the region is near the same previous forecast with the higher terrains could see another 4-9 inches through Thursday. The low lands could see another 1-4 inches. The best potential these amounts is over the Waterville Plateau down to Wenatchee and Leavenworth. The timing of the snow is is expected to cause morning commute issues for the Cascades valleys through the morning. Pockets of freezing precip are possible south of I-90 near Moses Lake through the morning. As the system continues East, warming temperatures could limit the snow amounts for Eastern Washington and the Idaho Panhandle for this afternoon with areas seeing an inch or two. By Thursday remnants of the wave will continue to bring light snow showers to the Idaho Panhandle with amounts up to inch possible. Highs for the period will be in the upper 20s to low 40s. Overnight lows will be in the upper teens to 20s. /JDC Friday through Tuesday: The Inland Northwest will begin a transition into a warmer and wet period as a flat upper level ridge shifts into the region. An active weather pattern within the Gulf of Alaska will keep a southwest flow aloft aimed at the Northwest with several embedded systems to pass through the region. Models continue to bring a weak front through the Pacific Northwest Friday night, with low confidence in measurable precipitation across the Inland Northwest. Most models keep precipitation over the mountains, but several members of the GEFS want to bring precipitation as far south as the Spokane area. Regardless, precipitation totals would be light. The most significant period of the extended forecast will be Saturday evening through Sunday as a moderate to strong atmospheric river takes aim at the northwest. With both the GEFS and ECMWF ensembles showing PWATS over the Inland Northwest increasing to 0.75+ inches, there is high confidence in widespread precipitation as a warm front lifts north Saturday night. Precipitation will fall primarily as lowland rain and mountain snow, although snow will be favored for the Methow Valley where cold air will take longer to fully scrub out. Following a period of cold and snow, these conditions raise concerns for rapid snowmelt across the lowlands, potentially leading to rises in smaller creeks and streams and localized field flooding. Areas of concern include Spokane County and the Washington and Idaho Palouse, where there is ample lowland snow and the GFS and NBM are indicating a 30 to 60% chance of rapid onset flooding during this time period. Paradise Creek in Moscow continues to be forecasted to exceed Minor Flood Stage Sunday night. Preparation ahead of this event is advised, such as clearing gutters and storm drains of compacted snow and debris to help minimize flooding impacts. Active weather will continue into early next week with models showing the next system to move into the PNW sometime between Monday and Tuesday. There are significant differences among ensembles in the exact timing though, but this will continue to be monitored. /vmt && .AVIATION... 18Z TAFS: Precip shield continues to move through central WA bringing periodic moderate snow to KEAT and snow to Moses Lake and Ephrata. The snow will move into the Spokane region within an hour to 90 minutes bringing IFR conditions. As temperatures warm, snow will change to rain at KGEG-KPUW between 20 and 23z. The warmer air overrunning the snowpack has a history of producing very low ceilings around Spokane and low visibility. Ceilings less than 1000 feet persist through 18z tomorrow, particularly KGEG- KSFF-KCOE-KMWH. FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: High confidence in IFR conditions as snow moves through the region. High confidence in very low cigs for KGEG after the snow ends tonight. ----------------------- Confidence descriptors: Low - Less than a 30 percent chance Moderate - 30 to 70 percent chance High - Greater than a 70 percent chance && .PRELIMINARY POINT TEMPS/POPS... Spokane 34 30 37 26 40 33 / 90 80 20 10 10 30 Coeur d'Alene 34 31 36 27 42 34 / 90 90 30 20 10 30 Pullman 36 31 35 25 38 34 / 100 90 40 10 0 20 Lewiston 40 34 42 25 42 36 / 90 80 30 10 0 10 Colville 34 27 39 28 40 30 / 90 60 10 10 30 50 Sandpoint 34 30 37 28 40 33 / 80 90 40 30 30 50 Kellogg 36 31 35 27 42 35 / 90 100 70 20 10 40 Moses Lake 38 29 43 28 41 30 / 100 10 0 0 10 10 Wenatchee 34 29 41 29 37 31 / 100 10 0 0 10 10 Omak 35 28 38 29 39 31 / 90 20 0 0 20 30 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...Winter Weather Advisory from noon today to 4 AM PST Thursday for Central Panhandle Mountains. WA...Winter Weather Advisory until 1 PM PST this afternoon for Moses Lake Area-Upper Columbia Basin. Winter Weather Advisory until 4 PM PST this afternoon for Central Chelan County-Waterville Plateau-Wenatchee Area- Western Okanogan County. Winter Weather Advisory until 4 AM PST Thursday for Western Chelan County. && $$