Gross Idaho Weather Forecast Discussion

154
FXUS65 KBOI 110956
AFDBOI
Area Forecast Discussion
National Weather Service Boise ID
356 AM MDT Sat Oct 11 2025
.SHORT TERM...Today through Monday night...An upper level trough
over southwest WA will slowly move eastward today and weaken.
Central and eastern OR remain in a dry slot of the system, with
dry conditions through this morning. The trough will move
eastward later today, with cooler air moving overhead by late
this afternoon. Snow levels fall to around 6000-6500` MSL this
afternoon, and temperatures at 500mb fall to around -25C,
causing steep lapse rates and unstable conditions this afternoon.
Periods of sunshine this morning and afternoon will be favorable
for scattered shower development late this afternoon and early
evening. Some of the stronger showers may produce graupel and
gusts up to 35 mph during the afternoon. Unstable conditions
continue into Sunday morning with rain and snow showers favored
over the higher terrain of the west central ID mountains. A
reinforcement of cold air from the north retrogrades into
another low pressure system off the Pacific NW coast on Monday,
shifting the flow to southwest again, with moderating
temperatures. Rain and snow showers possible over central and
eastern OR on Monday morning, with precipitation generally
staying west of a line from Ontario OR to Rome OR.
.LONG TERM...Tuesday through Saturday...A cutoff low pressure
system moves south along the coast and digs into southern NV/CA
by Wednesday with wrap around subtropical moisture impacting
the area Tuesday and Wednesday. Todays model suites now favor
upper level ridging on Thursday and Friday with warmer
temperatures. While both the deterministic and ensemble guidance
show good agreement on the overall pattern, forecast confidence
remains low due to the extreme amount of energy coming out of
the western Pacific due to the typhoons moving into the jet
stream upstream of us. Notably Typhoon Halong and the
interaction with the jet stream as it becomes a hurricane force
low in the Bering Sea this weekend. These complex interactions
have historically been poorly handled by the model suites and
this time will be no different. TLDR, the forecast will change
greatly each day even if there is good model agreement in the
extended over the next week due to the tropical systems upstream
of us.
&&
.AVIATION...VFR. Scattered showers developing in the afternoon.
Mountains obscured at times. Snow levels 7500-8500ft MSL,
lowering to 6000-6500ft this afternoon. Surface winds: W-NW
5-15kt, gusts to 15-30kt in the afternoon. Stronger showers may
produce gusty winds up to 35kt and graupel. Winds aloft at
10kft MSL: SW 20-35 kt becoming W-NW 10-20kt by Sat afternoon.
KBOI...VFR. 30 percent chance of showers in the afternoon.
Surface winds: NW 5-10 kt, becoming 10-15kt with gusts 25 kt in
the afternoon.
Sunday Outlook...Mountains obscured. Rain/snow showers
continue into Sunday with snow levels 5k-6kft MSL. Periods of
low VFR/MVFR in rain, IFR/LIFR in snow mainly in eastern OR.
Surface winds: generally SW-NW 10-15 kt, gusts to 20-25 kt.
&&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...None.
OR...None.
&&
$$
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SHORT TERM...KA
LONG TERM....KA
AVIATION.....KA

NWS BOI Office Area Forecast Discussion