Area Forecast Discussion
Issued by NWS Boise, ID
Issued by NWS Boise, ID
242 FXUS65 KBOI 170235 AFDBOI Area Forecast Discussion National Weather Service Boise ID 835 PM MDT Sun Jun 16 2024 .DISCUSSION...PoP, QPF, and snow amount forecasts have been updated through Monday night based on latest model trends and hi-res info. Models have trended gradually wetter since this morning especially in northern zones. Radar imagery at 8 PM MDT showed scattered light rain showers in eastern Oregon and beginning to enter western Idaho near Farewell Bend and the Owyhee Mountains. No changes were made to Temp, wind, and thunderstorm forecasts. The very cold upper low center is forecast to move eastward across our northern zones Monday but will still be close enough to continue showers (snow above 5000 feet MSL) in Idaho north of the Snake Basin Monday night. Warming trend starting Tuesday will lead to hot weather late next week, possibly reaching 100 degrees in the lower southern valleys Saturday. && .AVIATION...Showers increasing overnight. Isolated thunderstorms developing Monday afternoon, mainly over the central ID mountains. Showers will be most numerous across Baker County OR and the west- central ID mtns. Snow levels 4500-6000 ft MSL. Areas of MVFR/IFR conditions developing and mountains becoming obscured as precipitation expands. Surface winds: W-NW 10-20 kt with gusts 20-30 kt tonight into Monday. Winds aloft at 10kft MSL: SW 15-25 kt, becoming W-NW 15-30 kt after Mon/09Z. KBOI...Rain showers developing between Mon/08Z and Mon/19Z. 20-40% chance of rain at the terminal during this period and temporary MVFR ceilings, with the highest chance late Monday morning. Surface winds: NW 5-10 kt, increasing to 10-20 kt with gusts 20-30 kt. && .PREV DISCUSSION... SHORT TERM...Tonight through Tuesday night...An upper low will bring unseasonably cool, showery, and windy conditions to the region on Monday. A cold front out ahead of it will move through tonight, accompanied by gusty winds to around 30 mph. Showers associated with the low initiate over SE Oregon this evening, then SW Idaho on Monday as the core of the low moves through central Idaho. The bulk of the showers and greatest precip amounts are expected in central Idaho. Snow levels lower to around 4500 feet with some light snow accumulations above 5000 feet, including McCall where around an inch of snow is forecast. Only minor road impacts are anticipated, and mainly in the early morning hours. Total snowfall amounts of 3 to 6 inches are forecast for the northern mountains above 6000 feet through late Monday. Shower chances and precip amounts are much lower in the valleys (20-40 percent chance with less than a tenth of an inch), including the Treasure Valley. Winds increase during the afternoon, especially in south-central Idaho east of Mountain Home where speeds/gusts will approach advisory levels (sustained near 30 mph with gusts near 45 mph). Marginal instability due to the cold air aloft will lead to a slight chance (less than 20 percent) of afternoon thunderstorms. Showers and winds diminish Monday night as the low exits to the east. A weak upper trough arrives from the northwest on Tuesday for a chance of showers/slight chance of afternoon thunderstorms (15-30 percent) in central Idaho. The unseasonably cool temperatures on Monday (15-20 degrees below normal) trend 5-10 degrees warmer on Tuesday. LONG TERM...Wednesday through Sunday...The cooler/showery/windy weather early in the week will be long forgotten by the end of the week as hot temperatures return. Southwest flow aloft develops midweek and lasts into next weekend, supporting a gradual warming trend each day. Highs are favored to reach the lower 90s in the valleys by Friday and mid-upper 90s Saturday and Sunday. There is not enough moisture in the flow to warrant any convection, although even limited moisture could yield afternoon convection as the heat builds. For now, the forecast remains dry. && .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.....JR SHORT TERM...BW LONG TERM....BW