Area Forecast Discussion
Issued by NWS Boise, ID
Issued by NWS Boise, ID
675 FXUS65 KBOI 201625 AFDBOI Area Forecast Discussion National Weather Service Boise ID 1025 AM MDT Thu Jun 20 2024 .DISCUSSION...A weak shortwave will move across the area today, bringing increased clouds this afternoon. This will keep a threat of showers and thunderstorms, mainly over northeast Oregon over the Blue Mountains, north of Baker City and McCall in Idaho, and a slight chance of showers and thunderstorms in southern Twin Falls County and areas east. Drier air will move in from the west, but there will be enough moisture for showers and thunderstorms to form over the central ID mountains and southern Twin Falls County on Friday afternoon. Then the flow aloft shifts to the southwest, bringing warmer conditions. There is a 40-60 percent chance of temperatures in the lowest valleys exceeding 100 degrees on Saturday, and 50-70 percent chance of exceeding 100 degrees on Sunday. Forecast on track with no updates. && .AVIATION...VFR. Surface winds: E-SE 5-15 kt. Winds aloft at 10kft MSL: S-SE 10-15 kt. KBOI...VFR. Surface winds SE 5-10kt, switching to NW 5-10kt after 18z/Thu. Weekend Outlook...VFR with clear skies. Hot temperatures will bring high density altitudes Saturday and Sunday. Surface winds W-SW 10-20kt during the afternoons, light during the night. && .PREV DISCUSSION... SHORT TERM...Today through Saturday night...A weak upper-level trough remains over the forecast area today, maintaining warm and dry conditions. Expect mostly clear skies, though smoke from a wildfire in southwest Owyhee County may cause hazy conditions this afternoon across southwest Idaho. Temperatures in the lower valleys will reach the low 90s today. A weak trough will pass through tonight into Friday, limiting the warming on Friday to 2-4 degrees above Thursdays high temperatures. High- resolution models indicate enough moisture for cumulus cloud development along the Idaho/Nevada border. A Pacific system will reach the British Columbia coast on Saturday, forming a ridge and creating a southwesterly flow aloft over the forecast area. This could bring the warmest temperatures of the year so far, with a 40-50% chance of the Treasure Valley seeing maximum temperatures reach 100 degrees or higher on Saturday. Historically, Boise`s first 100-degree day typically occurs around July 7th, though in 5 of the last 11 years, it has happened in June. LONG TERM...Sunday through Thursday...Hot temperatures will persist on Sunday, with highs forecasted to reach around 100 degrees in the Treasure Valley. The Pacific system from the Gulf of Alaska will move across British Columbia on Sunday, bringing a surface cold front toward the forecast area from the northwest. This front, along with cooler temperatures, will not reach the area until Monday, providing a brief respite from the heat. Temperatures will drop into the mid-90s on Monday. However, hot and dry weather will continue through Wednesday. A much stronger Gulf of Alaska trough is expected to move inland starting Thursday, initiating a cooling trend. Ensembles show good agreement on this shift occurring late next week. && .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...KA AVIATION.....KA SHORT TERM...JDS LONG TERM....JDS