348 FXUS65 KBOI 060209 AFDBOI Area Forecast Discussion National Weather Service Boise ID 809 PM MDT Sat Nov 5 2022 .DISCUSSION...A few light sprinkles of rain and a few snow flurries have been observed around the area this evening, but mostly dry conditions will prevail overnight. Patchy early morning fog is possible especially in higher mountain valleys. Westerly winds will continue to slacken overnight and then become southeasterly on Sunday. The forecast remains on track for rain and snow to move back into the area on Sunday night. && .AVIATION...Generally VFR conditions, with periods of MVFR in light/moderate showers over higher terrain through this evening. Mountain obscurations. Pockets of mountain valley fog Sunday morning. Precipitation will return late Sunday afternoon/evening creating periods of MVFR conditions and mountain obscurations. Surface winds: W-NW 10-20kt with gusts 25-35kt, decreasing to variable 5-15kt after 00z/Sun. Winds aloft at 10kft MSL: NW 40-55kt becoming NW 25-40kt by 00z/Sun. && .PREV DISCUSSION... SHORT TERM...Tonight through Monday night...Surface cold front, marked by a line of showers, has moved south to the Snake River as of 130 PM MDT. However, clouds still cover our CWA except in northern Baker and Valley Counties where clearing has started. The cold front also marks the northern edge of the strong winds. Winds will therefore decrease in southern-most Idaho by late afternoon. Tonight will bring gradual clearing from north to south and also cooler temperatures as the supporting upper trough expands southward from western Canada and the nearby Pacific. The trough will dig southward most strongly along the coast Sunday and Sunday night leaving our CWA under strong southwesterly flow aloft and an east to west surface pressure gradient. The pressure gradient will result in breezy easterly winds Sunday. As the upper trough and low move south, rain and snow showers will increase in our CWA Sunday night and Monday. Late Monday night the upper low will be along the northern California coast and showers will decrease in Oregon, but will continue in south-central Idaho under moist southwesterly flow aloft. Temperatures will be near normal through Monday, then lower to slightly below normal Monday night. LONG TERM...Tuesday through Saturday...A large and cold low pressure center is anticipated to move southward along the west coast on Tuesday, and progress eastward on Wednesday. With unstable cold air aloft and associated moisture with the low, a chance of rain/snow showers is forecast across southeast Oregon and southwest Idaho for these days. Chilly, northwest flow will develop aloft later on Wednesday and into Thursday that will support gusty northwest winds at the surface, especially Wednesday when the pressure gradient will be strongest. Beginning Thursday, models are depicting drier conditions as weak high pressure is expected to build into the area. However, ensemble model guidance suggests great forecast uncertainty after Thursday. Overall, expect temperatures to drop around 10-15 degrees below normal by mid-week to late week. && .BOI WATCHES/WARNINGS/ADVISORIES... ID...None. OR...None. && $$ www.weather.gov/Boise www.facebook.com/NWSBoise www.twitter.com/NWSBoise DISCUSSION...JB AVIATION.....AL PREV SHORT TERM...LC PREV LONG TERM....SH