Area Forecast Discussion
Issued by NWS Spokane, WA
Issued by NWS Spokane, WA
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651 FXUS66 KOTX 241924 AFDOTX Area Forecast Discussion National Weather Service Spokane WA 1224 PM PDT Fri May 24 2024 .SYNOPSIS... Showers will continue across northeast Washington and north Idaho through the early morning. Friday will feature warmer temperatures with chances for afternoon and evening showers and thunderstorms. Saturday will be cooler with breezy winds and light precipitation. Dry weather returns on Sunday with temperatures warming into the 70s to low 80s on Memorial Day. A return of cool, wet weather is expected to return midweek. && .DISCUSSION... Today and Saturday: The morning will be benign for most across the region. Lingering showers will continue over North Idaho through mid morning as yesterdays shortwave continues to slide East. Ensembles are in good agreement for another system impacting the region Friday afternoon. A Gulf of Alaska Low will bring a shortwave into the Pacific Northwest. It will shift the upper level flow pattern from Northwest to Southwest. Ensembles are showing a decent plume of moisture and instability moving over Southeast Washington and the Lower Idaho Panhandle including Lewiston. Thunderstorm timing is expected to be around 1PM-6PM. A weaker area is once again Northeast Washington and the North Idaho Panhandle. Impacts include gusty winds, small hail, and lightning. Precip in these areas could reach up to 0.2". The rest of the region could see an isolated rain shower with little to no accumulation. Highs for the day will be in the 60s and low 70s. Lows will be in the 40s. For Saturday, the region will transition to a zonal flow pattern as the trough shifts East. Any shower activity will mainly be over the mountain areas of the Inland Northwest. The threat of thunderstorms is weaker than Friday but can`t rule out an isolated lightning strike with these showers. will be cooler than Friday with highs in the upper 50s and 60s. Lows will be in the upper 30s and 40s. /JDC Sunday through Thursday: Zonal westerly flow will prevail on Sunday, resulting in mainly dry conditions with the exception of a 30 percent chance of afternoon showers over orographically favored areas - i.e., the Cascade Crest and higher terrain right along the Canadian border. We`ll wake up to rather chilly temperatures Sunday morning in the mid to upper 30s, but after sunrise we will quickly warm to temperatures that are more typical for this time of year in the 60s and 70s. A ridge will begin to amplify over the region on Monday, squashing any remaining shower chances and sending temperatures well into the 70s and even low 80s for some spots. With a light breeze of 5 to 15 mph and mostly sunny skies, Monday will be a beautiful day for any outdoor plans. Temperatures on Tuesday will be even warmer than those on Monday, and highs nearing 90 won`t be out of the question for the deep Columbia Basin southeast of Moses Lake. Current ensembles are giving this area a 10 to 20 percent chance of hitting the 90s on Tuesday. A cold front is expected to move through sometime in the Tuesday afternoon/evening timeframe, bringing returning chances for showers and thunderstorms. Southeast WA, northeast WA, and the Idaho Panhandle have a 30 percent chance of seeing convective showers and thunderstorm development Tuesday. Following the passage of the cold front, temperatures will drop back down to seasonal normals in the upper 60s to mid 70s Wednesday and Thursday. A trough tracking through southern BC will likely bring chances for showers along the border each afternoon through the end of the week. /Fewkes && .AVIATION... 18Z TAFS: Upper level trough dropping into the region will result in building cumulus clouds through the afternoon with spotty showers across the northern mountains and extreme SE WA and the lower Idaho Panhandle. There is a 10-20% chance for t-storms around the Blue Mountains and Camas Prairie. For Lewiston proper, percentages are closer to 10% leading to low confidence to include in the 18Z TAFS. Energy with the upper-level disturbance will swing through overnight with a band of showers but largely VFR skies. Added prob30 groups to account for this activity. This will also come with a 20-40% chance for brief MVFR ceilings with the highest probabilities along an axis from Pullman,WA to Mullan, ID. Winds will remain elevated overnight at 10-15 mph. Winds will continue to increase on Saturday mainly after 18z. FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: There is moderate confidence (50% chance) for showers at times across the Idaho Panhandle, Northeastern WA, and between the Blue Mountains and Camas Prairie. Confidence is low for lightning coverage as any storms come off the higher terrain of NE OR into the lower Idaho Panhandle. A few models indicate a small potential (10%) for a few lightning strikes overnight with the showers. Confidence is low for MVFR conditions overnight given the increasing winds. Feel best chances will be around St Maries, Kellogg, and Mullan. ----------------------- 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 67 45 60 39 65 45 / 10 30 40 10 0 0 Coeur d`Alene 66 46 57 40 62 44 / 20 40 60 10 0 0 Pullman 65 43 56 38 63 43 / 30 60 30 10 0 0 Lewiston 72 51 65 44 71 49 / 40 70 30 0 0 0 Colville 67 40 59 34 64 38 / 40 40 80 20 10 0 Sandpoint 63 44 55 40 60 42 / 40 60 80 40 0 0 Kellogg 63 46 54 41 60 45 / 30 60 70 30 0 0 Moses Lake 72 44 68 39 72 45 / 10 10 10 0 0 0 Wenatchee 68 46 64 44 69 48 / 10 10 10 0 0 0 Omak 70 46 66 39 72 45 / 20 30 30 0 0 0 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...None. && $$