Area Forecast Discussion
Issued by NWS Boise, ID
Issued by NWS Boise, ID
920 FXUS65 KBOI 122039 AFDBOI Area Forecast Discussion National Weather Service Boise ID 239 PM MDT Wed Jun 12 2024 .SHORT TERM...Tonight through Friday night...Little change from previous forecast. Hotter Thursday as an upper ridge moves in from the west. Significant cooling beginning Friday as a deep upper trough in the Gulf of Alaska moves onto the northwest coast. Friday looks 6-10 degrees cooler than Thursday, and Friday night 6-10 degrees cooler than Thursday night (and even cooler after that). Models show limited moisture but enough instability for a slight chance of thunderstorms in Twin Falls County late Thursday/Thursday evening. Light winds tonight and most of Thursday, then westerly 20 to 30 mph in Harney County/OR Thursday afternoon and evening, and in southern Idaho Friday afternoon behind a surface cold front. .LONG TERM...Saturday through Wednesday...An active pattern will develop over the extended period, offering a break from summer heat and a brief return to more springlike conditions. The core of an upper level trough will move by to our north Saturday into early Sunday, bringing a dry cold front with much cooler temperatures and breezy winds. Any chance (10-20%) for showers will be limited to the northern mountains. Highs on Saturday will be 10-15 degrees cooler than Friday with another 5 degrees cooling on Sunday. This will place lower valley highs in the upper 60s to near 70 on Sunday, which is 10-15 degrees below normal. Models continue to show a closed low moving through the Pacific Northwest and Northern Rockies Sunday through Tuesday. The exact track of this low will have a major impact on our weather, with a more southerly track bringing the potential for widespread rain (and high-elevation snow above 7000 feet MSL in the central Idaho mountains) and temperatures 15-25 degrees below normal. This southerly track is depicted by roughly half of the EC ensemble members but is much less prominent amongst the GFS ensemble. A more northerly track would limit chances of showers and thunderstorms to the northern mountains, but still bring continued cool temperatures and breezy winds. By late Tuesday and Wednesday, models project the upper level trough to lose amplitude and temperatures to rise closer to normal, with drier conditions and decreasing winds also expected. && .AVIATION...VFR and mostly clear. Surface winds: W-NW 5-15 kt, with gusts 20-25 kt KBOI southeast through the Magic Valley terminals. Winds becoming variable 10 kt or less tonight. Winds aloft at 10kft MSL: W-SW 15-25 kt. KBOI...VFR under clear skies. Surface winds: NW 7-13 kt with gusts up to 20 kt this afternoon, decreasing this evening and becoming variable 6 kt or less by 06Z/Thu. && .BOI WATCHES/WARNINGS/ADVISORIES... ID...None. OR...None. && $$VFR under clear skies. Surface winds: NW 7-13 kt with gusts up to 20 kt this afternoon, decreasing this evening and becoming variable 6 kt or less by 06Z/Thu. www.weather.gov/Boise Interact with us via social media: www.facebook.com/NWSBoise www.twitter.com/NWSBoise SHORT TERM...LC LONG TERM....ST AVIATION.....ST