621 FXUS66 KOTX 060950 AFDOTX Area Forecast Discussion National Weather Service Spokane WA 250 AM PDT Sat May 6 2023 .SYNOPSIS... Cooler than normal temperatures will persist through the weekend. Widespread rain showers will continue through today across the Northern Mountains before drying mid-day Sunday. Cooler and unsettled weather will be the main story for the first half of next week. A warming trend will take over for the second half of the week. && .DISCUSSION... Today and tomorrow: Rain will continue through Sunday morning near the Cascade Crest, Northern Mountains, and Idaho Panhandle. Most locations will see less than a tenth of an inch of rain except far north WA/ID Panhandle. Flood advisories are still valid in Shoshone/Okanogan/Chelan as rivers are still running high from snowmelt and past rain. Flood watches are still valid in the northeast where rain is still falling. Rain amounts will be the greatest in extreme NE WA/Extreme N Panhandle around 0.5 to 1.0 inch. Deer Park/Cda will likely see less than 0.1 inch given the sharp gradient in the deformation band. Late Sunday morning/afternoon looks drier as a shortwave ridge moves into the region. That will keep us dry through Monday morning. Temperatures will peak in the upper 50s to low 60s today and tomorrow. Lows will be in the low to mid 40s. db Monday through Wednesday: Widely scattered showers and isolated thunderstorms are expected to impact the Inland Northwest Monday and Tuesday courtesy of a shortwave trof ejecting through the region. The shortwave is forecast to swing from the coast into Oregon on Monday then northeast through Eastern WA and North Idaho Monday night and Tuesday. The focus for showers and storms will start across southern WA and the lower Idaho Panhandle Monday afternoon then expand northward with time as the deeper forcing arrives. There are still some notable differences with the evolution of this wave which will have ramifications on the cloud cover and resultant instability that evolves Monday. Southeastern WA and the lower Idaho Panhandle carry the highest probabilities of CAPE in excess of 200 J/kg with the latest ensemble package advertising probabilities of 35-50% (>200 J/kg) and a 15-20% (>450 J/kg). Probabilities are roughly half of these percentages for the remainder of region. Nonetheless, there should be enough lift along the incoming shortwave to deliver another unsettled Monday afternoon/evening with showers likely to persist well through the overnight hours and into Tuesday. The shortwave will be limping across the region Tuesday. Cooler air aloft coupled with sun- breaks will allow for a renewed threat for showers and weak storms in the afternoon with the greatest risk for lightning shifting into northern Washington and Idaho where we find a 15-30% for CAPEs greater than 200 J/kg. Storms on Monday afternoon will have the potential for gusty outflow winds up to 30 mph, otherwise the main concerns with any developing storms will be brief downpours and lightning strikes. The trough will drift eastward Wednesday but these features are typically slow to move out which will keep a mention of showers and storms across the Idaho Panhandle and Northeastern WA. High pressure will start to blossom over Western Canada as low pressure resides over the Desert Southwest. This will result in a split flow pattern with the northern branch or higher pressure becoming the more dominant feature for our region. Consequently, Wednesday will feature a warming and drying trend for most areas across Central WA and only a 10-20% chance for showers over the eastern third of the forecast area. Thursday - Sunday: There is increasing confidence for another warm, drying trend late this week as high pressure strengthens over the Western US. Nearly 100% of the ensembles are dry for Thursday- Saturday before showing some uncertainty by late weekend into early next week. Typically, ridges of this magnitude are more stubborn than progressive so would anticipate the warmth to persist into early next week but the jury is still out on those details. Temperatures will be warming from the 70s Thursday back into the 80s by the weekend. The stable weather pattern would also support an abundance of sunshine and light, terrain driven wind fields. Below are the chances via the NBM for a few locations reaching the 80F mark once again. /sb Location Chance >80F FRI Chance >80F SAT Chance >80F SUN ------------------------------------------------------------------------------------ Spokane 60% 90% 90% Moses Lake 60% 90% 90% Omak 60% 90% 90% Colville 40% 80% 90% Sandpoint 20% 50% 70% Lewiston 70% 95% 90% && .AVIATION... 06Z: Showers will continue overnight and into tomorrow, impacting KCOE through the night. The best area for showers will be north of the TAF locations, but the axis of rain could sag south into KGEG/KSFF aft 16Z and continue for KCOE. Cigs will generally remain MVFR, but some localized IFR cigs, especially across the northern WA/ID valleys is possible. && .PRELIMINARY POINT TEMPS/POPS... Spokane 58 44 63 43 66 43 / 50 30 20 10 30 40 Coeur d'Alene 54 44 60 42 66 42 / 70 40 30 10 30 40 Pullman 57 42 60 42 64 41 / 40 20 20 20 60 50 Lewiston 63 47 67 47 69 48 / 40 10 30 20 50 50 Colville 55 43 62 41 67 40 / 80 50 40 10 40 30 Sandpoint 50 44 55 42 64 42 / 90 60 70 10 40 40 Kellogg 50 46 56 43 63 43 / 80 40 50 10 50 40 Moses Lake 65 42 69 45 69 43 / 10 10 0 10 30 40 Wenatchee 63 45 66 45 66 45 / 10 10 0 0 40 30 Omak 60 46 68 47 67 45 / 50 30 10 10 30 30 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...Flood Watch through this evening for Northern Panhandle. WA...Flood Watch through this evening for Northeast Mountains- Okanogan Highlands-Okanogan Valley. && $$