689 FXUS65 KBOI 230219 AFDBOI Area Forecast Discussion National Weather Service Boise ID 819 PM MDT Thu Apr 22 2021 .DISCUSSION...Radar showed a few weak echoes this evening in Idaho, none in Oregon. A couple of lightning strikes were detected near McCall early this evening. With the air mass so dry it will be heard for rain to reach the ground so near zero PoPs are good for tonight. Dry Friday and Friday night as a Pacific short wave ridge passes through. Showers and a chance of thunderstorms will begin Saturday as a Pacific trough comes inland. Models agree that the trough will take until late Monday to pass all the way through our CWA so the whole duration looks wet. Current forecast is on track. No updates. && .AVIATION...VFR. Isolated showers and thunderstorms this evening, clearing after sunset. Surface winds: NW 10-20kt with gusts up to 30kt possible at KBNO KTWF KJER, becoming light after sunset. Winds aloft at 10kft MSL: NW 15-25kt. Weekend Outlook...An upper level trough approaching the northwest coast will spread showers across the area on Saturday. Precipitation will be widespread on Sunday as the trough moves inland. Snow levels near 5000-6000ft MSL on Saturday will lower to 4000-5000ft MSL on Sunday. Isolated afternoon and evening thunderstorms also both days. Expect mountain obscuration and periods of MVFR/IFR conditions. && .PREV DISCUSSION... SHORT TERM...Tonight through Saturday night...Starting to see some shower activity enter our northern zones (Baker, Adams, and Valley counties) this afternoon. Shower and possible thunderstorm development will continue across the w-central Idaho mountains and far NE Baker county through this evening. A sprinkle is possible to the south of these areas, but the less favorable environment and dry near-surface conditions will work against seeing any measurable precipitation. The gusty winds this afternoon across open terrain will diminish this evening. Friday and Friday night will be dry under a passing short wave ridge. A fast moving upper trough will push into the Pacific NW on Saturday, increasing the chance for precipitation across the area. Instability and dynamics aloft will support a slight chance of thunderstorms from southeast Oregon into w-central Idaho. Southwest flow aloft will mix to the surface across higher terrain and could mix down with showers/storms at lower elevations. In both cases, gusts of 30 to 40 mph are possible. Precipitation will scatter out Saturday night as the initial wave lifts northeastward. Snow levels of around 7000 feet early Saturday will drop to 4500-6000 feet Saturday night with light to moderate accumulations limited to above 6500 feet. Temperatures will be above normal Friday cooling to around normal on Saturday. LONG TERM...Sunday through Thursday...An upper level trough will remain over the region through Monday, bringing cooler temperatures, showers, and unsettled conditions. Snow levels will be around 4000- 6000ft. While this system will bring showery conditions, the central ID mountains will average 0.5-1.0 inches of total precipitation through Monday, with valley locations like the Snake Basin and eastern OR seeing less than a half inch with this system. Snow accumulations will be limited to the mountain peaks above 7000ft. There will be a threat of thunderstorms on Sunday and Monday afternoons, with the cold air and steep lapse rates aloft. An upper level ridge will build over the region on Tuesday through Thursday. Temperatures will be around 5-10 degrees below normal on Sunday and Monday before warming back up to around normal by Tuesday and 5 to 10 degrees above normal on Wednesday and Thursday. && .BOI WATCHES/WARNINGS/ADVISORIES... ID...None. OR...None. && $$ www.weather.gov/Boise www.facebook.com/NWSBoise www.twitter.com/NWSBoise DISCUSSION...LC AVIATION.....JDS PREV SHORT TERM...DG PREV LONG TERM....KA