Sumpter, Oregon Weather Forecast Discussion

018
FXUS65 KBOI 152002
AFDBOI
Area Forecast Discussion
National Weather Service Boise ID
202 PM MDT Mon Sep 15 2025
.SHORT TERM...Tonight through Wednesday night...Clouds
and isolated showers in the West-central Idaho Mountains
and Boise Mountains should dissipate by sunset as the
weekend`s upper low moves ese-ward across WY and away
from our CWA. The rest of our CWA was already clear as
of 1 PM MDT. Skies will stay clear in all areas through
Wednesday night as an incoming upper ridge replaces the
departing low. The ridge will also bring warmer daytime
temps, with highs 5 to 8 degrees above normal by Wednesday.
Nights will stay cool, though, and patchy fog will form
in northern valleys around sunrise Tuesday and Wednesday.
Breezy northwest winds early this evening, otherwise light
diurnal winds through Wednesday night.
.LONG TERM...Thursday through Monday...Sunny and warm
Thursday with the upper ridge still over our area. A degree
or two warmer Friday under southerly flow aloft behind the
departing ridge. Latest models show a weak short wave trough
approaching from Calif Friday bringing middle and high clouds
Friday night. Low levels will stay dry and PoPs will stay
less than 10 percent. A stronger upper trough from the Gulf
of Alaska is also forecast to come inland Saturday leading
to 10-20 percent chance of showers along with cooler temps
Saturday afternoon through Sunday. Drier, breezy, and warmer
Monday as a broad, flat, Pacific upper ridge comes in behind
the weekend trough.
&&
.AVIATION...VFR. Isolated rain showers in the west central
Idaho mountains until sunset. Generally clear elsewhere,
Patchy valley fog and low stratus in northern mountains
around sunrise Tuesday. Surface winds: variable 5-10 kt.
Winds aloft at 10kft MSL: NW 10-15 kt.
KBOI...VFR. Few afternoon cumulus, otherwise clear. Surface
winds: NW around 10 kt until 16/00Z, then light and variable.
&&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...None.
OR...None.
&&
$$
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SHORT TERM...LC
LONG TERM....LC
AVIATION.....LC

NWS BOI Office Area Forecast Discussion