399 FXUS66 KOTX 111105 AFDOTX Area Forecast Discussion National Weather Service Spokane WA 305 AM PST Sun Nov 11 2018 .SYNOPSIS... High pressure will deliver dry weather through Tuesday with a mix of low clouds and fog in the valleys of northeast Washington and north Idaho. Precipitation chances will likely return to the region either late Tuesday night or Wednesday. More dry weather will return Friday and Saturday. && .DISCUSSION... Today: As of 3 AM, fog has spread into the upper Columbia Basin with visibility of a half mile or less reported at Moses Lake and Wenatchee. Washington DOT cameras along I-90 suggest fog is common from west of Spokane to Ritzville to Coulee City and Davenport. Compared to yesterday, low clouds and fog are more prolific. The ground around Moses Lake, Coulee City, and Wenatchee isn't as wet as around Spokane, Colville, and Sandpoint. The newly formed fog/low cloud deck isn't as thick either, so the low clouds in the Columbia Basin may erode more easily today. If it does, places like Moses Lake and Ritzville will have a shot climbing into the low to mid 40s. If clearing doesn't occur until late afternoon, temperatures will languish in the 30s. Tonight: The NAM, GFS, and other mesoscale models forecast an increase in boundary layer easterly winds this evening following a shortwave passage down the Continental Divide. Will the increased mixing be enough to disperse what is left of the low stratus deck this evening? Forecast soundings suggest that 6 to 9 hours of easterlies just above the surface will be enough to erode the low clouds. If clearing does come to fruition, it may only be temporary. Decreasing winds by morning (just above the surface) will likely promote redevelopment of fog especially in the sheltered valleys north and east of the metro. Monday and Tuesday: Our low level inversion will strengthen Monday and Tuesday as the 500 mb ridge axis migrates inland. Areas that can stay free of fog and stratus will have the potential to warm up nicely. Afternoon temperatures have the potential to reach the 40s. The low clouds will be the wild card. Needless to say, there is the potential for big temperature busts with this forecast. /GKoch Wednesday and Wednesday night: A shortwave trough of lower pressure will knock down the high pressure ridge on Wednesday. The bulk of the dynamics will push across southern BC. Dynamics along the cold front will be strongest across the northeast portion of the region late Wednesday morning into the afternoon then weaken as it slides into the southern ID Panhandle by the evening. The northern mountain valleys are expected to wetbulb down to snow with light accumulations possible. A late morning to early afternoon timing for snow should limit the amount of snow that will accumulate on the roads, so I don't think it will be a high impact event. Snow levels will also be rising through the afternoon, so I think impacts will also be minimal for travel going over Lookout Pass. Winds will pick up a little bit behind the front with breezy conditions possible across the exposed areas of the basin and into the Spokane Area and Palouse. Wind gusts of up to around 30 mph is expected. The winds will increase the mixing and should scour out the fog/stratus that has continue to develop across the region. As a result, temperatures will actually feel more mild with frontal passage in the afternoon. Thursday through Sunday: High pressure will rebound over the region. Models don't show the ridge becoming quite as strong. It will increase the potential for more fog and stratus though. Good confidence that dry conditions will be in place until the start of next weekend. There is a chance for precip to return by the end of next weekend, but confidence is very low. /SVH && .AVIATION... 06Z TAFS: Low clouds and fog with IFR conditions will continue to impact the aviation area through the next few days under a strengthening upper-level ridge. Anticipate persistent stratus and fog at KGEG and KSFF. At KCOE, the afternoon clearing lead to dense radiational fog which may gradually raise overnight. KPUW may see some local fog, although the easterly flow should keep them mostly VFR, likewise the same for KLWS. The main changes were KMWH where the stratus and fog has moved in and should remain into the morning hours. May even these conditions reach the KEAT area toward morning. Kept the general trend of poor conditions through 18z, then a slow improving trend during the afternoon and evening. Confidence is low on the reforming of the stratus/fog for Sunday evening. /rfox. && .PRELIMINARY POINT TEMPS/POPS... Spokane 35 24 38 26 41 30 / 0 0 0 0 0 0 Coeur d'Alene 36 23 40 25 42 29 / 0 0 0 0 0 10 Pullman 38 24 41 28 45 31 / 0 0 0 0 0 0 Lewiston 43 27 46 30 47 34 / 0 0 0 0 0 0 Colville 37 24 39 24 41 29 / 0 0 0 0 0 10 Sandpoint 38 24 40 24 44 28 / 10 0 0 0 0 0 Kellogg 37 22 40 26 41 29 / 10 0 0 0 0 0 Moses Lake 40 23 43 24 40 27 / 0 0 0 0 0 0 Wenatchee 45 27 44 29 43 32 / 0 0 0 0 0 10 Omak 47 25 46 27 42 30 / 0 0 0 0 0 10 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...None. && $$