Area Forecast Discussion
Issued by NWS Boise, ID
Issued by NWS Boise, ID
946 FXUS65 KBOI 240946 AFDBOI Area Forecast Discussion National Weather Service Boise ID 346 AM MDT Fri May 24 2024 .SHORT TERM...Today through Sunday night...An upper level trough will move into our forecast area today as an upper level ridge moves east. Temperatures will be around 10 degrees warmer than yesterday in response to the departing ridge. A cold front associated with the trough will move into eastern Oregon this afternoon and into southwest Idaho by mid to late this evening. Weak instability in place as the front moves through will support showers and isolated thunderstorms. The core of the upper level trough will move across our northern areas, resulting in the highest chance of precipitation (60-90%) in these areas. Elsewhere, a 20-50% chance of showers will develop. Snow levels will be high today, generally around 8000 feet MSL. Gusty winds may accompany the frontal passage and near thunderstorms with brief gusts to 40 mph possible. The trough will slowly move east into Saturday, keeping chances of showers going mainly across the mountains and eastern areas. Snow levels will drop to 5500-7000 feet, allowing for minor snow accumulations on high peaks. A 5-10 degree temperature drop is anticipated on Saturday behind the front. Breezy winds will develop as the trough exits our area, with gusts generally 20-35 mph, except up to 40 mph in the Magic Valley. Dry conditions and lighter winds will return Sunday as an upper level ridge builds overhead. A warming trend will begin that will continue into the extended period. .LONG TERM...Monday through Friday...Sunny skies and above normal high temperatures should prevail throughout most of the region as a relatively dry but progressive flow pattern dominates. Dry, stable ridging will start the period off on Monday but quickly transition into a series of back-to-back low pressure system migrations beginning Tuesday. The majority of their associated moisture and instability will stay well to the north of the region with a brushing by affect occurring across the northern sections the forecast area. This effect, in turn, will set up low probabilistic (15 - 35%) chances for showery activity in those sections from Tuesday afternoon through Thursday. The possibility for afternoon thunderstorms will be enough to mention the slight chance for occurrence Tuesday afternoon supported by the initial trough passage. With the flow pattern initially taking on a southwestly trajectory, this will draw up a few pockets of moisture into the Twin Falls area providing the ingredients for afternoon thunderstorms across the mountains on Tuesday afternoon. Periods of breezy wind conditions are expected across the Steens, Trout Creek, and Owyhee Mountain Ranges as pressure gradient tightenings occur with each trough system transition. High temperatures are expected to range from the high 70`s through the mid 80`s - cooler during the trough passages. && .AVIATION...Mainly VFR. Patchy mountain valley fog this morning, including near KMYL. Scattered showers and isolated thunderstorms developing in eastern OR this afternoon along a cold front, moving across SW Idaho this evening. Mountains obscured in showers with brief MVFR/IFR conditions in storms. Snow level around 8kft MSL. Surface winds: E-SE 5-10kt, becoming NW 10-20kt with gusts to 35kt along and behind the front. Gusty and erratic winds near thunderstorms. Winds aloft at 10kft MSL: W-SW 10-20 kt. KBOI...VFR. SE 5-10 kt, shifting to NW 5-15 around 02-05Z/Sat, with brief gusts to 30 kt along a cold front. Scattered light rain showers developing this evening. Weekend Outlook...Mainly VFR. Lingering showers on Saturday, mainly in the mountains. MVFR/IFR possible in precip, along with mountain obscuration. VFR and dry Sunday. Snow levels generally 5500-7500 ft MSL. Surface winds W-NW 10-20 kt with gusts 20-35 kt Saturday. Sunday winds W-NW 5-15 kt. Winds strongest in the Magic Valley. && .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....WH AVIATION.....ST