Area Forecast Discussion
Issued by NWS Boise, ID

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067 FXUS65 KBOI 280941 AFDBOI Area Forecast Discussion National Weather Service Boise ID 341 AM MDT Tue May 28 2024 .SHORT TERM...
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Today through Thursday night...Active weather is anticipated today as an upper level trough over the eastern Pacific moves inland today. Southwest flow aloft will strengthen as this feature approaches southeast Oregon and southwest Idaho, bringing even warmer temperatures and increasing moisture. Highs will reach the upper 80s in the lower valleys, with a 20-40% chance to hit 90 degrees. Instability will develop this afternoon ahead of the trough, and shower and scattered thunderstorm development will favor the higher terrain. However, the approaching trough will provide lift for storm formation and will aid storm organization and movement into lower valleys including the Treasure and Magic valleys. Storms may become strong to severe with wind gusts to 60 mph the primary hazard, but hail and heavy rain will also be possible. Showers and thunderstorms will decrease overnight as the trough and a cold front push through, with most activity limited to the central Idaho mountains after midnight MDT. The cold front will move across the area this evening, reaching the Magic Valley near or shortly after midnight MDT. Gusts to 45 mph are possible along the front, but could be stronger if thunderstorm outflows enhance the front. This may result in blowing dust reducing visibility. Much cooler and drier air will arrive behind the cold front on Wednesday. Dry conditions will return with temperatures nearly 20 degrees cooler than today. Winds will be breezy as the trough passes through, bringing gusts 20-30 mph, except up to 40 mph in the Magic Valley. Thursday will be very similar to Wednesday as dry northwest flow aloft sets up behind the trough, keeping temperatures around 5 degrees below normal. Additionally, winds will be lighter, but still breezy across the Magic Valley. .LONG TERM...Friday through Tuesday...Models are in generally good agreement with regard to the large-scale pattern through early next week, but there are some differences with respect to short-wave troughs embedded in a westerly flow aloft. A weak upper trough could move through over the weekend, but precip chances remain slim (less than 20 percent) and confined to the far north. A more impressive trough could arrive early next week, but there are significant differences in its strength. There is a low (15-30 percent chance) of rain showers across the northern areas starting Sunday night and continuing into Tuesday. Near normal temperatures are favored on Friday, warming to slightly above normal temperatures for the remainder of the period. There is at least a 60 percent chance that high temperatures exceed 80F in portions of the Snake Plain from Saturday until Tuesday, including Boise.
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&& .AVIATION...
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Mainly VFR. Variable mid-high level clouds increasing through the day, mainly in the afternoon and evening. Dry through 18Z, then low-moderate confidence (30-60 percent chance) of showers and thunderstorms after 18Z. Some of the thunderstorms will be capable of producing MVFR conditions accompanied by +RA, small hail, and strong gusty outflow winds up to 50 kt. Surface winds: E-SE 5-15 kt becoming mainly SW-W after 18Z, except variable gusty/erratic winds near thunderstorms. 10k ft MSL winds: SW 15-30 kt. KBOI...VFR with mostly clear skies in the morning and increasing mid- high clouds in the afternoon. Winds SE around 12 kt becoming NW around 10 kt after 18Z. Low chance (20%) of thunderstorms in the vicinity between 28/22Z and 29/00Z. Higher chances (50%) after 29/00Z with gusty outflow winds to 30 kt.
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&& .BOI WATCHES/WARNINGS/ADVISORIES... ID...None. OR...None. && $$ www.weather.gov/Boise Interact with us via social media: www.facebook.com/NWSBoise www.twitter.com/NWSBoise SHORT TERM...ST LONG TERM....BW AVIATION.....BW