663
FXUS65 KPIH 061741
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
1141 AM MDT Sun Sep 6 2026

.KEY MESSAGES...

- Marginal Severe Risk Sunday Evening: A SPC Marginal Risk
  covers most of eastern Idaho today. Warm afternoon
  temperatures in the upper 70s to lower 80s combined with
  strong wind shear will support scattered thunderstorms capable
  of strong to severe downburst wind gusts (4050+ mph) late
  Sunday afternoon and evening.

- Breezy Southerly Winds Today: Southerly winds of 15 to 25 mph
  with gusts of 30 to 40 mph will develop this afternoon ahead
  of the primary convective line.

- Labor Day Cooldown: Highs on Labor Day Monday will drop
  significantly into the 60s for most locations, followed by the
  coldest night of the week Monday night as valley lows fall
  into the 40s and high country basins drop into the 30s.

- Pleasant & Seasonal Mid-Week Recovery: High pressure and dry
  air return Tuesday through Friday, lifting temperatures back
  to seasonal norms in the upper 70s and lower 80s before the
  next trough approaches next weekend.

&&

.DISCUSSION...
Issued at 212 AM MDT Sun Sep 6 2026

Early morning satellite imagery shows the stagnant Pacific
Northwest upper-level low finally making eastward progress
across Oregon. Banded cloud cover and showers continue to stream
around the eastern flank of the system, maintaining active
weather over the Central Mountains early this morning. High-
resolution convective-allowing models (CAMs) indicate mountain
showers will taper off around or shortly after sunrise, yielding
a brief mid-day lull across the forecast area.

This lull will be short-lived as the parent low advances closer
to Idaho. Strong dynamic lift and surface heatingpushing
valley highs into the upper 70s and lower 80swill yield
sufficient instability and kinematics for organized convection.
The Storm Prediction Center (SPC) maintains a Marginal Risk
across much of eastern Idaho for strong to severe thunderstorm
wind gusts. Most daytime hours will remain pleasant with
increasing clouds, as convective development holds off until
after 5:00 or 6:00 PM. Southerly surface winds ahead of the main
line will increase to 1525 mph with gusts reaching 3040 mph.
Convective activity will persist through the evening and early
overnight hours before diminishing toward Labor Day morning.
While the overall storm system has trended drier compared to
earlier model runs, localized heavy downpours remain possible
beneath stronger convective cores.

Labor Day Monday will be markedly cooler behind the cold front,
with daytime highs capped in the 60s across most valley
locations, though a few spots near the Utah border may briefly
touch the lower 70s. Showers will wane by Monday afternoon,
leaving dry but cool conditions for the evening. Clear skies and
cold advection Monday night into Tuesday morning will result in
the coldest temperatures of the week, with high country basins
dropping into the 30s and lower elevation valleys falling into
the 40s. Tuesday will be pleasant, dry, and seasonably cool.

Temperatures moderate rapidly back toward seasonal averages on
Wednesday, with valley highs returning to the upper 70s and
lower 80s. High pressure and general zonal upper flow will keep
conditions mostly dry and uneventful through Friday, though
isolated higher-terrain showers cannot be entirely ruled out as
short-range hi-res guidance may better resolve subtle impulses.
The next potential for widespread precipitation arrives next
weekend as global models track an upper-level trough southward
out of Western Canada. However, considerable ensemble spread
remains regarding the depth, track, and associated surface
impacts of this feature.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1141 AM MDT Sun Sep 6 2026

Quiet conditions are in place early this afternoon, but we begin
to transition to breezy conditions with increasing moisture and
a threat for SHRA/TSRA by evening for all terminals. A few TSRA
will be able to generate gusts approaching 45kts, and will
maintain going PROB30 timing. Storms decrease overnight west to
east, but SHRA remain possible. Winds remain elevated overnight
into Monday morning as well, strongest at PIH and IDA where
sustained speeds will likely hover around 20kts and gusts around
30kts.

&&

.FIRE WEATHER...
Issued at 212 AM MDT Sun Sep 6 2026

Scattered thunderstorms arriving late this afternoon and evening
present the primary operational hazard today. Strong convective
downdrafts capable of producing erratic wind gusts exceeding
4050 mph will be possible across all dispatch zones after 5:00
PM. Ambient southerly wind gusts of 30 to 40 mph will also
develop this afternoon ahead of the storms. Wetting rains will
accompany stronger storm cores tonight before drier, much cooler
air arrives on Labor Day. High relative humidity recoveries are
expected Monday night as temperatures drop into the 30s and 40s,
followed by a warm, dry trend mid-to-late week.

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

DISCUSSION...McKaughan
AVIATION...DMH
FIRE WEATHER...McKaughan