Claude, Oregon Weather Forecast Discussion

176
FXUS65 KBOI 210252
AFDBOI
Area Forecast Discussion
National Weather Service Boise ID
852 PM MDT Sat Sep 20 2025
.DISCUSSION...
Isolated showers and thunderstorms near the Nevada border are
weakening this evening, with very weak flow aloft resulting in
slow storm motions. A couple outflow boundaries were moving
northward towards the Treasure Valley, with a minor increase in
winds associated with these. Trends suggest isolated showers
may continue or redevelop into the late morning across southwest
Idaho. More widespread shower and thunderstorm development
still appears likely in the afternoon as a cold front arrives,
especially across western and central Idaho.
&&
.AVIATION...VFR. Areas of showers expected in southwest Idaho
through Sunday morning. Isolated thunderstorms developing after
21/19Z, primarily affecting Idaho terminals. Brief heavy
rainfall, gusty winds to 35 kt, and small hail possible. Threat
for showers/thunderstorms ending late Sunday evening.
Surface winds: Variable overnight, becoming W-NW 5-15 kt with
gusts to 25 kt after 21/17Z. Winds aloft at 10kft MSL:
W at 10-20 kt.
KBOI...VFR. A few showers in the area Sunday morning, followed
by isolated thunderstorms in the afternoon. 30% chance of the
terminal being affected after 21/21Z, with brief heavy rain,
gusty winds to 35 kt, and small hail possible. Decreasing threat
after 22/02Z with VFR overnight. Surface winds: SE 5-10 kt,
becoming W-NW 6-12 kt Sunday afternoon.
&&
.PREV DISCUSSION...
SHORT TERM...Tonight through Monday night...A ridge remains
over the area today with warm temperatures continuing. Mid
level moisture from a system in northern CA is fueling isolated
showers and thunderstorms, mainly along the NV border and the
Blues in OR, and south of the Snake Plain in ID. Gusty outflow
winds up to 40 mph possible in the vicinity of storms. A trough
from the Gulf of Alaska will bring a cold front to the area on
Sunday, which will interact with the moisture already in place.
Scattered showers and isolated thunderstorms form early Sunday
morning ahead of the front, and intensify with the daytime
heating on Sunday afternoon as the front moves east. The shower
threat diminishes in the late afternoon as drier air moves into
the area. The front will bring breezy west-northwest winds
during the afternoon Sunday with gusts up to 20-30 mph. Upper
level ridging returns on Monday with dry conditions, and breezy
west- northwest winds continuing in the Treasure and Magic
Valleys on Monday.
LONG TERM...Tuesday through Saturday...Summer heat looks to
stick around a while longer, as a potent upper-level ridge
will build in and intensify over the area starting Tuesday. This
will create a classic omega block pattern over the U.S., with a
upper-level low pressure system over California and another
over the midwest. High temperatures will be 5 to 10 degrees
above normal during this time. Overnight Wednesday into
Thursday, the California upper-level low begins to get caught in
the flow and move further into the mainland United States.
Before it fully moves east out of our region by Saturday, the
northern extent of the low and associated moisture is not well
agreed upon by the GFS, ECMWF, and Canadian. The GFS keeps the
center of the low along our southern border with Nevada, while
the ECMWF and Canadian stay south. There is good spread of
differences between the ensemble guidance as well, which could
either lead to dry and temperate conditions or shower activity
with cooler temperatures. This should get ironed out within the
next few deterministic runs, but certainly is something to watch
for any weekend plans.
&&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...None.
OR...None.
&&
$$
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DISCUSSION...JR
AVIATION.....JR
SHORT TERM...KA
LONG TERM....CH

NWS BOI Office Area Forecast Discussion