456
FXUS65 KPIH 101129
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
529 AM MDT Thu Sep 10 2026

.KEY MESSAGES...

- Red Flag Warning in the Snake River plain and Teton Valley
  noon to 8 PM MDT today for low humidity and gusty wind.

- Breezy to windy conditions continue through Sunday, but
  higher humidity will eliminate Red Flag conditions.

- Light showers may return to the eastern and southern highlands
  late tonight into Friday morning. Heavier showers at scattered
  or lower coverage, and thunderstorms at isolated coverage,
  for Saturday and Sunday.

&&

.DISCUSSION...
Issued at 148 AM MDT Thu Sep 10 2026

Today through Sun...Upper level trough moving through southern
Canada will dig far enough south to increase wind in southern
Idaho today to significant thresholds for Fire Weather. A closed
low that develops off the end of this trough slowly meanders
onshore and moves through the ID panhandle and western MT Sat
night and Sun. Wind appears even stronger on Sun when the close
low`s southeast corner overlays the entire forecast area.

The closer the low gets, the cooler temperatures will be. Thus
today will be the warmest overall. Temperatures cool slightly on
Fri, then level off on Sat, then cool down 14 to 20 deg F from
Sat afternoon to Sun afternoon.

The trough passing by today does appear to entrain some moisture
northward into the southern and eastern highlands in the
forecast area by late tonight into Fri morning. A slight chance
of thunderstorms develops in the southeast corner of the
forecast area. By Sat and Sun, showers and thunderstorms will
overspread the forecast area, with Sat having the greatest
coverage, then the pattern shifting eastward and mostly out of
the central Idaho mountains.

Sun night through Wed...Dry zonal flow sets up in the wake of
the upper level low. This will mean are return to warming,
getting to near climatic normals by Tue afternoon. The moderate
to strong upper level westerly flow will mean gusty afternoons
as inversions break. Dewpoints will fall, and so critical fire
weather conditions may return for some of the zones during this
period.

&&

.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 524 AM MDT Thu Sep 10 2026

After several days of clear and a million with fairly light
wind, a significant change develops in the late afternoon,
11/00Z, give or take an hour. Wind will be taking on a southwest
component with G25KT and even later G30KT. Wind stays
elevated, except perhaps at KSUN, starting in the early evening.


CIGs stay at mid-level heights around the same time, and SHRA
should start developing. Currently, it does not look unstable
enough for TS. SHRA may get to consistent -SHRA at the very end
of the current TAF valid times.

Not expecting any impact to VSBY.

&&

.FIRE WEATHER...
Issued at 148 AM MDT Thu Sep 10 2026

An upper level trough moving southward, but staying in Canada,
will bring moderate to strong wind for today through Sat,
mainly in the afternoon, then a closed low moving in from the
west will punch up the wind even stronger on Sun. So overall it
will be a breezy to windy four days ahead.

This will combine with very low humidity today, and possibly
tomorrow, as humidity expected in some areas to sink below 15
percent. After coordination with dispatch staff, a Red Flag
Warning was issued for today in Fire Weather Forecast Zone 410,
the BLM lands in the Idaho Falls District.

Over the weekend, the temperatures will cool and humidity spike
upward as showers and thunderstorms arrive on account of this
closed low. Do not expect any critical fire weather conditions
over the weekend as thunderstorm activity should be isolated in
coverage.

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning from noon today to 8 PM MDT this evening for
IDZ410.

&&

$$

DISCUSSION...Messick
AVIATION...Messick
FIRE WEATHER...Messick