FXUS66 KOTX 181058 AFDOTX Area Forecast Discussion National Weather Service Spokane WA 258 AM PST Wed Dec 18 2024 .SYNOPSIS... The passage of a cold front today will create wind gusts as high as 50 mph across the Palouse and Columbia Basin. The rest of the week will feature mild temperatures and a trend of more wet weather towards the weekend into next week. && .DISCUSSION... Today through Thursday Night: Tricky forecast with mixed precipitation across the region. Stevens Pass is seeing freezing rain this morning. The cold front will push through in the next hour or two, and should transition precip back to snow. In addition, there is a 60-70% chance of an inch an hour snowfall briefly early this morning. Will keep the winter storm warning going through 10am. Snow chances will decrease after 10am. Winthrop sensor stopped reporting at midnight, but looking at other sensors from around the Methow Valley, temps are still below freezing. Will keep the winter weather advisory going until 10am as there is likely snow or freezing rain occurring. The Okanogan Valley had freezing rain last night. Latest report from Omak shows the temperature has warmed to 33 degrees, and freezing rain is coming to an end. Other sensors in eastern Okanogan county and Ferry county show temperatures have warmed in the valleys, with light snow likely to continue above 3500 ft through late this morning. Will let advisory expire at 4am. Across NE WA and N ID...Sandpoint is in the process of transitioning to rain, as seen by the airport sensor, and also a spotter who called from the Hope area. Locations like Colville and Bonners Ferry are still holding on to some colder air and snow continues. Expect temperatures to warm and snow to become wet with not much further accumulation. Other areas like Spokane area, Palouse, LC Valley are quite mild this morning w temps in the upper 30s to mid 40s. As the front pushes through this morning, expect winds to increase after 6am and continue through the morning and decrease after 1pm. Probabilities of seeing gusts to 50 mph stands at about 30-50% across the eastern Columbia Basin, Spokane area and Palouse. There is an 80-90% chance of seeing gusts to 40 mph for those areas as well as along Highway 2 west of Spokane and onto the Waterville Plateau. Precipitation will move out of the area this afternoon with a quiet night of forecasting stratus and fog for the region. The shortwave ridge will out as quickly as it moved in. Another weather system will move in Thursday and Thursday night providing snow for Cascades once again. Northern WA and ID mountains have a 20-30% chance of seeing some light snow above 3-4k ft. /Nisbet Friday through Wednesday: A strengthening ridge over Central Conus will keep the Pacific Northwest under warm Southwest flow pattern. Several systems will push through the Inland Northwest generating decent precip for the period. The warm air does not lead to a good snow setup for elevations below 4000ft. The period will mainly be a mountain snow and lowland rain. Ensembles are expecting light mountain shower activity for Friday before a more widespread precip event on Saturday. It will then be followed by a cold front late Sunday, early Monday that will weaken the ridge. It will bring another round of widespread mountain snow and lowland rain. The Inland Northwest can expect widespread showers through the Wednesday. Depending on the precip falling during the day or night, lowland areas North of Hwy 2 could receive snow overnight. Isolated pockets of freezing rain are possible in the Cascade Valleys but probabilities of more than a trace are less than 30%. Highs for the period will be in the 30s to low 40s. Lows will be in the 20s to low 30s. /JDC && .AVIATION... 06Z TAFS: Warm frontal precipitation will clear the Spokane, Coeur d'Alene, and Pullman airports by 08z. Once in the warm sector, low level wind shear will increase across the southern Idaho Panhandle and the eastern third of Washington. The mixing associated with increasing winds should break up the low stratus until the cold front arrives between 12-16z. Another brief period of rain will spread across eastern Washington and north Idaho followed by gusty west winds. Gust of 30 to 35kts are expected for KGEG, KPUW, KSFF, and KLWS from late morning through late afternoon. FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: Low confidence of when ceilings will lift around Moses Lake and Wenatchee. The HREF suggests enough warm sector mixing prior to 12z for improving conditions, but it may be after cold frontal passage (15z) before west winds disperse the low clouds and areas of fog. /GKoch ----------------------- 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 46 30 39 32 39 32 / 90 0 0 10 0 0 Coeur d'Alene 45 29 39 32 40 32 / 90 0 0 10 0 0 Pullman 46 30 41 33 42 34 / 80 0 0 0 0 0 Lewiston 56 33 45 36 47 35 / 40 0 0 0 0 0 Colville 44 24 36 30 37 29 / 90 0 10 20 0 10 Sandpoint 42 28 37 31 39 31 / 100 0 10 20 0 10 Kellogg 42 31 42 33 41 32 / 90 0 0 10 0 0 Moses Lake 49 30 43 33 41 32 / 30 0 10 0 0 0 Wenatchee 44 30 37 32 37 32 / 30 0 10 10 0 0 Omak 40 25 37 32 36 30 / 50 0 10 10 0 10 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...Winter Weather Advisory until 4 AM PST early this morning for Northern Panhandle. Wind Advisory until 1 PM PST this afternoon for Coeur d'Alene Area-Idaho Palouse. WA...Winter Weather Advisory until 4 AM PST early this morning for Central Chelan County-Northeast Mountains-Waterville Plateau-Wenatchee Area. Wind Advisory until 1 PM PST this afternoon for Lower Garfield and Asotin Counties-Spokane Area-Upper Columbia Basin- Washington Palouse-Waterville Plateau. Winter Storm Warning until 10 AM PST this morning for Western Chelan County. Winter Weather Advisory until 10 AM PST this morning for Western Okanogan County. && $$