textproduct: Boise

DISCUSSION

An upper level trough and cold front which brought today's breezy conditions and morning showers will continue to pull away from the area. An upper level ridge will build in behind the departing trough, with winds tonight becoming light and a few high clouds moving overhead. This will allow low temperatures to dip into the 20s in the lower elevations, with 10s common in the mountains. Highs on Tuesday will be near normal. The next system is still on track to bring rain and snow to northern areas beginning Tuesday night. No updates to the forecast this evening.

AVIATION

VFR. Patchy fog overnight. Increasing clouds with snow showers developing over the mountains and mountains becoming obscured Tue afternoon. Surface winds: variable up to 10kt becoming E-SE 5-10kt Tue afternoon. Winds aloft at 10kft MSL: W-NW 20-30kt increasing to W-NW 30-40kt by 00z/Wed.

KBOI...VFR. Surface winds: variable 5kt this evening becoming SE 5-10kt overnight.

PREV DISCUSSION

SHORT TERM...Tonight through Wednesday night... Breezy northwesterly winds gusting to 30 to 40 mph from Mountain Home east across the western Magic Valley behind today's cold front. Colder air being ushered into the area along with breezy winds will completely mix out the valley inversion today with seasonally cold/cool temperatures expected tonight and Tuesday with dry conditions. Winds will diminish late today with the pressure gradient relaxing overnight and light winds prevailing Tuesday.

An upper level ridge will bulge north over Idaho and Oregon Tuesday and Wednesday. This will force the Pacific moisture plume a little further north keeping the chance of precipitation Tuesday night through Wednesday night across northern areas. Baker county through the West Central Mountains of Idaho have the highest chance for precipitation with generally a 50 to 70 percent chance for any 12 hour period. Snow levels will be around 3000-4000 feet Tuesday night and rise to 5000-6000 feet Wednesday and Wednesday night. Precipitation amounts will be light with snowfall totals Tuesday night through Wednesday night generally in the to 1 to 5 inch range above 5000 feet, the majority of which will fall Tuesday night into early Wednesday when snow levels are the lowest. Temperatures will gradually trend up on Wednesday with daytime highs slightly above normal.

LONG TERM...Thursday through Monday...A warm frontal passage Thursday morning will usher with it mild temperatures (around 5 degrees above normal) and increased precipitation chances (30-60%) across higher terrain north of the Snake Plain. A cold frontal passage late Thursday/early Friday will help modulate temperatures closer to normal. This cold front and trailing upper-level shortwave will keep elevated precipitation chances north of the Snake Plain through Friday morning, before beginning to taper off through Friday afternoon. Snow levels on Thursday start out at 5-6 kft MSL behind the warm front, lowering to 4-5 kft by Friday behind the cold front. These snow levels mean that Thanksgiving morning, mountain valleys could see a wintery mix before transitioning to rain during the day. Minimal travel impacts are expected. For those in and south the Snake Plain, it should be a decent day for a turkey trot, bowl, or whatever your traditions may be.

There is increased uncertainty in the pattern evolution Friday and beyond. There is good model consensus on a trough digging down...just how that trough digs down is uncertain. In general, GFS members close off a low over our area and dig a trough down to SoCal from Manitoba, Canada. This is the colder and wetter solution. Euro members dig the trough down a little more east and not nearly as deep, this is a warmer (relative to the GFS) and drier (again, relative to the GFS) scenario. In either scenario, below normal temperatures are favored Sunday/Monday. A drying trend is also common in both solutions come Monday.

BOI WATCHES/WARNINGS/ADVISORIES

ID...None. OR...None.