Area Forecast Discussion
Issued by NWS Boise, ID
Issued by NWS Boise, ID
030 FXUS65 KBOI 280224 AFDBOI Area Forecast Discussion National Weather Service Boise ID 824 PM MDT Mon May 27 2024 .DISCUSSION...Isolated thunderstorms are popping up over Harney County as of 8:00pm MDT. These will likely weaken as the evening progresses, with continued dry conditions with warm overnight easterly winds expected over the rest of the region into the night. Several areas reached the mid-80s this afternoon for their daily highs, with still higher temperatures expected tomorrow. This will allow for widespread instability to form ahead of the shortwave trough and cold frontal passage tomorrow. Strong thunderstorms look to begin by late afternoon (~3-5pm MDT) over the Magic Valley and early evening (~5-7pm MDT) over southeast Oregon-Treasure Valley. The strongest storms with gusty winds and hail looks to be over Baker County, OR and northern portions of Malheur County, OR, especially as the cold front moves in by early tomorrow night. Forecast looks to be on track for the next few days, so no updates are necessary. && .AVIATION...VFR through late Tuesday morning with intermittent cloudiness over eastern Oregon. Thunderstorm chances increasing Thursday afternoon at KBKE/KBNO and KTWF/KJER, with low confidence (30% chance) of directly affecting terminals. Scattered storms may develop near KEUL/KONO close to 29/00Z. Surface winds: E-SE 5-15 kt overnight, becoming W 10-15 kt in W of KBOI after 18/17Z. Gusty outflow winds possible. 10kft MSL: SW 15-30 kt. KBOI...VFR with mostly clear skies. Winds becoming SE around 12 kt after 28/05Z. W winds around 10 kt likely by 28/19Z. Low chance (20%) of thunderstorms in the vicinity between 28/22Z and 29/00Z. Higher chances (40%) after 29/00Z with gusty outflow winds possible. && .PREV DISCUSSION... .SHORT TERM...Tonight through Wednesday night...Any lingering showers over Harney county this evening will dissipate shortly after sunset taking with them the chance for locally gusty outflow winds. Tuesday will be an active day as a shortwave trough will swing into Pac NW. Morning virga showers, indicative of increasing moisture and instability aloft, are possible over far SE Oregon and SW Idaho. By early afternoon, dynamic forcing ahead of the trough, coupled with increasing instability and surface energy will spur thunderstorm initiation over SE Oregon and higher terrain of southwest Idaho. The shear environment would favor development of stronger, longer-lived storms capable of producing gusty outflow winds and hail. Gust potential is in the 50-60 mph range. Given the pattern have gone with scattered coverage (25-35%) for thunderstorms Tuesday afternoon/evening. Areas that don`t pick up thunderstorm outflow winds will see gusty winds accompanying the cold front passage Tuesday evening. Gust potential with the front is up to 45 mph, but could be stronger through SE Oregon and portions of the Snake Plain if enhanced by thunderstorm outflow. Winds of this scale and speed could produce blowing dust which would reduce visibility. The chance for showers and thunderstorms contracts into the w-central Idaho mountains Tuesday night as the upper wave lifts into MT. Winds remain breezy behind the front Tuesday night, and will maintain speed on Wednesday as flow aloft mixes to the surface. The chance for mountain showers will decrease on Wednesday as the air mass stabilizes in the wake of the departing low. A late spring roller coaster of temperatures will play out as highs from Tuesday to Wednesday will drop nearly 20 degrees. For lower elevations temperatures of near 90 on Tuesday will fall off to around 70 on Wednesday. .LONG TERM...Thursday through Monday...Deterministic and ensemble model solutions are favoring the development of a less amplified W-NW flow pattern through the weekend. However there is still uncertainty in details regarding minor waves embedded in the flow. For now carrying dry conditions through Sunday with a low chance of showers returning on Monday. After Thursday temperatures are on the upswing warming back above normal for Sat/Sun/Mon which will place lower valleys into the 80s and mtns near 70. && .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 DISCUSSION...SA AVIATION.....JR SHORT TERM...DG LONG TERM....DG