


Area Forecast Discussion
Issued by NWS Spokane, WA
Issued by NWS Spokane, WA
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965 FXUS66 KOTX 220045 AFDOTX Area Forecast Discussion National Weather Service Spokane WA 545 PM PDT Mon Jul 21 2025 .KEY MESSAGES... - Showers and thunderstorms with heavy rain this evening. Heavy rain will increase the potential for flash flooding near burn scars. - Isolated to scattered thunderstorms region-wide Tuesday. - Warmer with breezy winds Thursday and Friday. && .SYNOPSIS... Slow moving showers and thunderstorms will impact the northern mountains this evening. Heavy rainfall will be the main concern with these storms. Showers and thunderstorms will develop again Tuesday across the Inland Northwest. A warming and drying trend will prevail Wednesday into Friday with breezy conditions returning Thursday and Friday. && .DISCUSSION... Tonight and Tuesday: Upper-level low has tracked into southern WA and will begin to slowly eject to the east on Tuesday. Moisture indices have been on the increase throughout the previous 24 hours with the 18z balloon data now showing almost 0.90" of precipitable water. Sunbreaks over Central and Northern WA will continue to fuel pulse thunderstorms with torrential downpours and lightning as the main threat. Spotters this afternoon have reported 0.50" in 30 min under some of the heavier cells. This threat will continue until sunset then wane into decaying showers. For Eastern WA and North Idaho, the thick blanket of clouds currently over the area will begin to slowly break up. This will bring a late day, small threat for some convective cells and a few thunderstorms. Best chance for organized thunderstorms this evening will be south of this cloud shield stretching from northeastern Oregon to Missoula. A few of these cells containing hail, gusty winds, and heavy downpours still have a 30% chance to skirt southern Asotin and Lewis Counties per the latest HRRR mainly before 9PM. Otherwise, scattered showers will rotate across northern WA through the night with generally light precipitation intensities. On Tuesday, showers wrapping around the backside of the low will pass through E WA and N ID in the morning then afternoon heating will promote afternoon instability with surface based CAPEs increasing between 500-1000 J/kg and CAPE through a deeper layer reaching -20C to -25C. This will bring the potential for a few stronger cells containing a combination of heavy rain and hail. Effective shear will be the limiting factor for organized updrafts as it only increases near 15kts. Higher CAPEs will compensate some and many hi-res models indicate a few cells tracking west to east through the northern tier of WA and N ID Tuesday evening that would likely need to be close attention to. This includes most communities along and north of Hwy 2 including Spokane-Cd`A. Isolated t -storms cannot be ruled out around Wenatchee, Moses Lake, and into Ritzville as well. Threat seems lower for Pullman, Lewiston, and Deary. Storms on Tuesday will also bring the potential for scattered to potentially frequent lightning strikes given the deeper instability into the ice growth zone. Wednesday through the weekend: There is good agreement in the ensemble clusters for weak ridging Wednesday which begins to flatten Thursday. A trough settles into the West Coast Friday into the weekend with tendency to retrograde by Sunday and Monday placing the Inland in southwest flow aloft. Wednesday`s flat ridge will deliver drier conditions and warming temperatures. Cumulus buildups are expected on the tail end of the departing low over North Idaho with a 20% chance for very light showers with little to no rainfall. Temperatures continue to warm on Thursday and remain in the 80s to lower 90s Friday with breezy conditions and elevated fire weather conditions. NBM introduced 20-40% chances for wind gusts of 30 mph in the lee of the Cascades and foothills of the Blue Mountains. Otherwise, wind gusts across much of the region will be in the 15-25 mph range. As the trough sets up along the WA Coast, there will be 10-20% chances for afternoon convection over the mountains near the Canadian border though this comes with low confidence for cells to set up south of the International border. All things considered, the Inland NW will be entering another dry period with warm temperatures and periods of breezy winds. /sb && .AVIATION... 00Z TAFS: A low pressure system spinning over eastern Washington will bring passing showers. Some stronger cells primarily over the mountains will have embedded thunderstorms. Coverage of convection this afternoon will decrease into the overnight hours with the loss of surface heating. The atmosphere will remain conditionally unstable on Tuesday under the trough of low pressure. Models indicate better instability with more potential for thunderstorms. Not enough confidence at this point to add thunderstorms to the TAFs. Generally light and variable winds across the region except for where convective outflows occur with convective cells. FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: High confidence for VFR conditions. The exception will be where covective cores pass through that may briefly drop visibility below 6 SM with MVFR conditions. There is a 15% chance for thunderstorms at KEAT-KGEG-KSFF-KCOE-KLWS this evening, and less than 10% chance at KMWH and KPUW. /SVH && .Preliminary Point Temps/PoPs... Spokane 57 78 56 87 60 90 / 40 50 20 0 0 0 Coeur d`Alene 56 77 54 86 59 89 / 50 60 30 0 0 0 Pullman 49 77 50 83 53 87 / 30 30 10 0 0 0 Lewiston 62 87 62 93 65 97 / 40 20 10 0 0 0 Colville 47 74 45 84 48 88 / 70 70 30 10 0 0 Sandpoint 52 70 49 81 54 85 / 70 80 50 0 0 0 Kellogg 56 70 56 81 61 86 / 60 70 40 0 0 0 Moses Lake 57 85 59 92 60 94 / 30 10 10 0 0 0 Wenatchee 62 85 64 92 66 93 / 50 40 20 0 0 0 Omak 58 85 58 92 60 94 / 60 40 10 0 0 0 && .OTX WATCHES/WARNINGS/ADVISORIES... WA...Flood Watch until 9 PM PDT this evening for Central Chelan County-Okanogan Highlands-Okanogan Valley-Wenatchee Area- Western Chelan County-Western Okanogan County. ID...None. && $$