734
FXUS65 KPIH 111130
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
530 AM MDT Fri Sep 11 2026

.KEY MESSAGES...

- Red Flag Warning in the Snake River plain and Teton Valley
  (Fire Weather Zone 410) today noon to 9 PM for low humidity
  and gusty wind. Fire Weather Watch on Saturday noon to 9 pm
  due to low humidity and gusty wind.

- Saturday afternoon temperatures warm for most, then Sunday
  afternoon temperatures cool 12 to 16 degrees, ending critical
  fire weather conditions. Windy conditions through Sunday.

- Isolated dry thunderstorms expected in the southeast corner of
  forecast area today, then again on Sunday but along Montana
  border.

&&

.DISCUSSION...
Issued at 145 AM MDT Fri Sep 11 2026

Today through Sun night...Strong upper level flow will be
mixing down to the surface. It should be stronger than
yesterday. Combined with continued very low humidity over a
slightly smaller portion of the lower elevations, Red Flag
Warning has been re-issued for the Idaho Falls WFS area, Fire
Weather Forecast Zone 410. The area of strongest wind shifts
farther southward on Saturday, and there is potential for low
humidity to continue there as well. The strongest wind is
expected Sunday, as a trough moving through over Sat night
brings the tightest gradient of the next three days.

The passage of the trough Sat night brings a strong cooling,
similar to something seen more in a winter regime, hinting at a
coming transition. Afternoon highs should cool 12 to 16 deg F
from Sat to Sun.

The expected rainfall amounts have collapsed to near zero for
this period. It is rainer this morning than any other period.
This was the trend yesterday with Sat returning to temperatures
warmer than Fri. The cool down previously from Sat to Sun was in
excess of 20 deg F. This is indicative of reduced cloud cover
and moisture.

Mon through Thu...A lingering troughing continues on Mon, so
there as an additional 2 to 6 deg F cooling. Warming returns Tue
as the Gem State sits between two highs, with a closed low
developing off the OR-WA coast. The ridges strengthen during
this period, thus bringing warmer temperatures, getting back
above normal for the time of year by Wed. It also should bring
lighter wind as early as Mon. Near zero threat of precipitation
or thunderstorm activity during this mid-range forecast period.

&&

.AVIATION /12Z TAFS THROUGH 12Z SATURDAY/...
Issued at 524 AM MDT Fri Sep 11 2026

Occasional light rain has cleared KSUN and KBYI. The clearing
line also somewhat lines up with the onset of gusty wind, which
will dominate the TAFs today. Not expecting any concerns with
impactful CIGs or VSBYs, with only KDIJ having morning -SHRA,
with KPIH having VCSH. Wind will peak with G35KT at KIDA, G30KT
at KDIJ and KPIH, G25KT at KSUN, and G20KT at KBYI.

Wind subsides during the evening 12/00Z to 12/04Z, depending on
location, but wind returns Sat afternoon. Strongest wind on Sun
afternoon.

&&

.FIRE WEATHER...
Issued at 145 AM MDT Fri Sep 11 2026

Strong upper level flow will be mixing down to the surface. It
should be stronger than yesterday. Combined with continued very
low humidity over a slightly smaller portion of the lower
elevations, Red Flag Warning has been re-issued for the Idaho
Falls WFS area, Fire Weather Forecast Zone 410. The area of
strongest wind shifts farther southward on Saturday, and there
is potential for low humidity to continue there as well. Thus a
Fire Weather Watch was issued for Fire Weather Zone 427 on Sat.
The strongest wind is expected Sunday, as a trough moving
through over Sat night brings the tightest gradient of the next
three days. However, the cooling keeps afternoon humidity well
above the 15 percent critical threshold. Temperatures bottom out
on Mon, as wind dies down strongly and high pressure returns to
the northern Great Basin.

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning from noon today to 9 PM MDT this evening for
IDZ410.
Fire Weather Watch from Saturday afternoon through Saturday
evening for IDZ427.

&&

$$

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