Area Forecast Discussion
Issued by NWS Boise, ID
Issued by NWS Boise, ID
562 FXUS65 KBOI 170236 AFDBOI Area Forecast Discussion National Weather Service Boise ID 834 PM MDT Mon Sep 16 2024 .DISCUSSION...At 830 PM MDT showers and thunderstorms were pivoting around an upper low centered in northern Nevada and moving east to west across our CWA. Stronger thunderstorms have had heavy rain, small hail, and gusty winds. A couple have had wind gusts to 60 mph. At 820 PM a severe thunderstorm was northwest of Mountain Home and moving toward the Boise metro-- should reach Boise 845-900 PM MDT and continue to move westward the city. Expect a strong hit from this storm. Earlier this evening thunderstorms dropped prolonged heavy rain on the Lava Fire burn-scar southwest of Cascade. We issued a Flash Flood Warning for that but the rains have since ended. For tonight, the main feature will be the current showers and thunderstorms working westward across our southern zones. Current forecast through Wednesday is in good shape as described in prev discussion (below). && .AVIATION...VFR, with MVFR possible in/around showers and thunderstorms. Thunderstorms through at least 06Z. Wind gusts to 50 kt possible with the strongest storms. Terrain obscuration over central Idaho. Surface winds W-NW 10kts, becoming light overnight. Winds at 10kft: SE-NE 10-20 kt. KBOI...VFR, with MVFR possible in/around showers. Thunderstorms moving west toward the airport at this time and will arrive by 9 PM MDT, with wind gusts to 50 kt likely. Showers to continue overnight into Tuesday, with periods of MVFR possible. Surface winds: variable due to several outflows through at least 10 PM MDT, then becoming variable less than 10 kt after midnight. && .PREV DISCUSSION... SHORT TERM...Tonight through Wednesday night...Active and unsettled weather to continue through at least Tuesday. A broad area of low pressure will work west to east through the region, with satellite and radar imagery indicating plenty of moisture available to generate showers/thunderstorms beginning later this afternoon/evening. Hi-res model guidance is also hinting at the potential for gusty winds with the strongest storms (20-40% chance of gusts over 30 mph), with peak gusts as high as 45 mph. Cloud cover will limit strong storm potential, with the highest probability of winds greater than 30 mph over south central Idaho and far southeast Oregon. The strong storm potential will wane quickly after sunset. Overnight the mid/upper level flow will begin to shift to the north and eventually northwest, with upslope enhancement anticipated across central Idaho for much of the day on Tuesday. Precip chances will hover between 60-90% Tuesday with abundant cloud cover and snow levels dropping below 10k feet. There is good agreement that another area of low pressure will drop to the southwest of the region Wednesday into Wednesday night, keeping temperatures 10-15 degrees below normal. LONG TERM...Thursday through Monday...A drier and seasonable stretch on tap for the end of the week and weekend. The low pressure system is expected to drift south and east of the region with dry northwesterly flow spilling in off the Pacific. This will allow for some warming, but temperatures will remain below normal through early 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...MC LONG TERM....JM