007
FXUS65 KPIH 281951
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
151 PM MDT Fri Aug 28 2026

.KEY MESSAGES...

- Unseasonably Cool & Active Weekend: Strong southwesterly flow
  between a West Texas ridge and a digging Pacific Northwest
  trough will draw deep moisture into eastern Idaho, keeping
  temperatures 10 to 15 degrees below normal (highs in the 60s
  and 70s) alongside widespread rain through Saturday.

- Saturday Severe Thunderstorm Risk: The Storm Prediction Center
  (SPC) has placed all of eastern Idaho in a Marginal Risk for
  severe storms on Saturday, with a localized Slight Risk across
  the far southeast corner (Pocatello south to the Utah border).
  Strong QG ascent, effective bulk shear exceeding 40 knots, and
  CAPE greater than 1000 J/kg will support supercells capable
  of localized severe wind gusts.

- Weekend Rainfall Distribution: Total precipitation through
  Sunday will range from ~0.10" across the central mountains and
  western zones to 0.15"0.50" in the Snake Plain, and
  0.50"1.00" across the Eastern Highlands.

- Fall-Like Early September: Broad troughing will persist over
  the Pacific Northwest through next week, keeping daytime highs
  cool and dropping overnight lows into the 40s and low 50s
  across lower elevations.

&&

.DISCUSSION...
Issued at 108 PM MDT Fri Aug 28 2026

Several waves in strong southwest flow will continue to push
moisture into southeast Idaho through Saturday. Will have
widespread rain showers through tonight. Complete overcast today
has kept temperatures from rising and have well below normal
high temperatures for the first time in awhile and this trend
will continue through Sunday. Thunderstorms have been slow to
develop today but still expect at least isoalted coverage this
afternoon. Saturday is more interesting with especially the
eastern zones in extensive shear and instability and much of
Idaho is in a marginal risk for severe thunderstorms and the
extreme southeast an even more elevated slight risk. High
temperatures Saturday mainly in the mid to upper 70s low
elevations and 60s to lower 70s mountains. Showers and
thunderstorms will continue overnight Saturday night into Sunday
with most thunderstorms by Sunday afternoon along the Wyoming
border as moisture finally moves east. Highs on Sunday again
mainly 60s mountains and 70s valleys.

Next week expect some warming back closer to normal but still
below with showers and thunderstorms mainly in the south Monday
and north on Tuesday. Highs in the 60s to 70s mountains and 70s
to lower 80s valleys. Expect mainly mountain isolated to
scattered showers and thunderstorms Wednesday through Friday
with some cooling expected once again with highs 60s mountains
and 70s valleys in the middle to latter part of next week. May
see some breezy to windy conditions next Tuesday into Thursday
with strong pre and post cold frontal passage winds.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1147 AM MDT Fri Aug 28 2026

Showers are ongoing across much of the area so far today. We will
watch for some clearing mainly over the southeastern corner of the
state this afternoon to see if we can get some isolated
thunderstorms going. There will likely be some isolated storms
embedded in afternoon showers, so continuing with VCSH and PROB30
groups. Confidence is a bit lower in storms impacting KSUN today and
as mentioned, we may need some clearing around BYI, PIH, and IDA to
get more robust storms there, so timing has been pushed back at
these sites a few hours. The best chance likely exists at DIJ this
afternoon. Expect another round of showers overnight into Saturday
morning with continued potential for storms Saturday afternoon at
all sites. Even with the cloud cover, VFR conditions are expected
aside from when a shower or storm moves directly over a terminal,
then we have seen brief drops to MVFR VIS.

&&

.FIRE WEATHER...
Issued at 151 PM MDT Fri Aug 28 2026

Our overall pattern is undergoing quite the change today as an area
of low pressure north of us moves eastward through the weekend.
Showers have been continued throughout the morning hours over much
of our coverage area. They will do so on and off throughout the rest
of today and we will watch for pockets of clearing this afternoon to
support some isolated to nearly scattered thunderstorm development
later this evening with this second round of showers and storms
expected through Fire Weather Zones 413 and 427 with some spillover
into 410 and 425. More showery activity will be found in our other
zones. PWATs continue to range from 0.80-1.10" throughout the area
and will remain elevated through at least the first half of Saturday
before falling on Sunday. So, while thunderstorms do become
scattered in coverage, storms are expected to be efficient rain-
makers, thus negating the need for Red Flag Warnings across the area
late today through Saturday. The highest rainfall amounts are
expected across the Eastern Highlands and in parts of the South
Hills, pushing the 0.50-0.75" range for total amounts by Sunday
evening. Elsewhere, look for about a tenth to a quarter of an inch
of rainfall. In addition to the moisture, we are seeing a
significant cool down across the area from upper 80s and 90s
yesterday to struggling to make it into the low to mid 80s this
afternoon. Highs will be in the 70s to near 80 on Saturday and
solidly in the low to mid 70s area wide by Sunday afternoon. A few
isolated storms will linger in the east on Sunday, but drier air
begins to quickly return and we will likely see a few areas out
across the desert return to min RHs in the teens on Sunday with
gusting winds of 25-30 mph. The overall pattern remains unsettled
during the week ahead with isolated rain and storm chances most
afternoons and long-range models showing another deep low impacting
the West in the second half of next week. Of course, we will see how
that trend continues over the next several days.

&&

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

&&

$$

DISCUSSION...GK
AVIATION...AMM
FIRE WEATHER...AMM