Area Forecast Discussion
Issued by NWS Boise, ID
Issued by NWS Boise, ID
918 FXUS65 KBOI 251550 AFDBOI Area Forecast Discussion National Weather Service Boise ID 950 AM MDT Wed Jun 25 2025 .DISCUSSION...Current water vapor imagery shows the first upper-level shortwave of a series of two making it through our area. This first shortwave is bringing with it a brief period of increased mid/high cloud cover. Temperatures this afternoon will make it to the mid-80s to low-90s throughout the Snake Plain. The second shortwave and associated cold front is currently off the coast of Oregon, but looking to move across our area this afternoon/evening. Weak instability building in ahead of this front continues to support a slight chance (15-20%) of thunder across Baker county and the west central Idaho mountains this afternoon/evening. Aside from that, most of our area will remain dry, with the only impact from the cold frontal passage being breezy winds from to west/northwest. Temperatures on Thursday will be a few degrees cooler than today following the frontal passage. Current forecast on track, no updates necessary. && .AVIATION...VFR. A 15% chance of showers and thunderstorms this evening with weak frontal passage near KBKE-KMYL. Surface winds: Light and variable less than 10 kt becoming E-SE 5-15 kt north and east of KEUL-KTWF, elsewhere SW-NW 10-15 kt with gusts to 25 kt after Wed/18Z. Winds aloft at 10kft MSL: SW 10-20 kt. KBOI...VFR with incoming mid-level clouds. Surface winds: SE 3-7 kt then W-NW 8-11 kt after Thu/05Z. && .PREV DISCUSSION... SHORT TERM...Today through Friday night...A weak cold front with middle and high clouds was gradually taking shape from eastern WA through central OR early this morning, supported by a weak upper trough along the northwest coast. A stronger upper trough was out in the Pacific along 135W. Satellite loop showed higher clouds near the front moving east, but the cold front itself should hold back until the stronger upper trough comes inland tonight. The front will then move eastward ahead of the incoming upper trough. Instability today will be marginal but enough for isolated weak thunderstorms in Baker County this afternoon. However, as the upper trough comes inland instability will increase for a 15-20 percent chance of thunderstorms continuing this evening in Baker County, and through the night and into Thursday in the West central Idaho Mountains. Southern parts of our CWA will stay dry with only a few hours of cloudiness as the front passes through. High temps today will be 3-6 degrees warmer than Tuesday in all areas, then 3-6 degrees cooler Thursday in Oregon and west central Idaho. Southern Idaho will barely feel the cold front Thursday except for a wind shift to west or northwest, with speeds only 10-15 mph at most. However, in the west central Idaho mountains outflow winds from thunderstorms could be as strong as 35 mph. Thursday night through Friday night should be partly cloudy in the north and mostly clear in the south, with little temperature change as the broad upper trough passes through. LONG TERM...Saturday through Wednesday...Saturday looks mostly sunny with normal temperatures with the broad upper trough still passing through. Sunday will begin a warming trend as the trough finally exits east and an upper ridge begins to build northward in the southern Great Basin. At the same time, a Pacific upper low will move toward the California coast. Southerly flow aloft ahead of the low will enhance the building Great Basin upper ridge and Monday will become hot in our CWA with high temps near 100F in our lower southern valleys. The upper low will also supply mid-level moisture for at least a 15 percent chance of high-based thunderstorms Sunday night in southeast Oregon, and Monday in southwest Idaho as well. The hot, dry weather together with high-based thunderstorms will create a significant fire-weather risk. && .BOI WATCHES/WARNINGS/ADVISORIES... ID...None. OR...None. && $$ www.weather.gov/Boise Interact with us via social media: www.facebook.com/NWSBoise www.x.com/NWSBoise DISCUSSION...NF AVIATION.....SA SHORT TERM...LC LONG TERM....LC