Area Forecast Discussion
Issued by NWS Boise, ID
Issued by NWS Boise, ID
387 FXUS65 KBOI 210226 AFDBOI Area Forecast Discussion National Weather Service Boise ID 826 PM MDT Thu Jun 20 2024 .DISCUSSION...Mid and high clouds this evening due to a weak short wave trough aloft moving eastward across the area. Sprinkles possible this evening in northern mountains. The trough will briefly slow the warming trend with Friday only about 3 degrees warmer than today. But Saturday will be hotter with an upper ridge building behind the departing trough. Latest models have Sunday a degree or two cooler than Saturday but still hot. Further cooling (5 to 8 degrees) Monday behind a dry cold front, then warming again Tuesday and Wednesday, with Wednesday almost as hot as Saturday. Models diverge after that with GFS bringing another cold front and cool upper trough inland while ECM keeps building the heat through Friday. Current forecast favors the cooler GFS but confidence is low. No updates for now. && .AVIATION...VFR. Surface winds: E-SE 5-15 kt. Winds aloft at 10kft MSL: S-SE 10-15 kt. KBOI...VFR. Surface winds NW 5-10kt, switching to SE 5-10kt around 21/06Z. Weekend Outlook...VFR. 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...Tonight through Saturday night...A weak shortwave will continue to 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. LONG TERM...Sunday through Thursday...The warming trend continues under southwest flow aloft on Sunday with a 50-70 percent chance of exceeding 100 degrees. A weak dry cold front moves through on Monday, with several degrees of cooling. Then, temperatures rebound on Tuesday as a trough off the Pacific NW coast amplifies the ridge over southwest Idaho and southeast Oregon. Temperatures warm to near 100 degrees in the lowest valleys on Wednesday. A cool 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...LC AVIATION.....SP SHORT TERM...KA LONG TERM....KA