FXUS65 KPIH 230806
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
206 AM MDT Sun Aug 23 2026

.KEY MESSAGES...

- Storm Prediction Center has areas of marginal chance and 
  slight chance of severe thunderstorms for today and tonight.

- Thunderstorms have less chance of occurrence, but greater
  severity potential today. 

- Breezy conditions in the central Idaho mountains and Snake
  River plain today, even outside thunderstorm activity.

&&

.DISCUSSION...
Issued at 138 AM MDT Sun Aug 23 2026

Southwest upper level flow will continue to bring moist and
unstable air into the forecast area. SPC now has an area along
the UT border that has a slight chance of severe thunderstorms,
meaining large hail or gusts in excess of 50KT/58MPH. The
marginal contour around it also covers a large amount of the
forecast area. It mainly leaves out the central Idaho mountains,
which are in general thunderstorm forecast area. The coverage of
thunderstorms shrinks on Mon and Tue. The best thunderstorm
coverage Mon is expected to be the highlands along the UT and WY
borders. Then on Tue it shift to the north along the MT border. 

Cloud cover actually decreases in the late morning, which is
what allows enough destabilization to increase the intensity if
not the coverage of the thunderstorms. Afternoon highs will be
cooler today after the cooler air moved in during the evening
and late night hours last night. 

The final thing is that a low moving onshore and through
southern Canada will push up the upper level wind over the
central Idaho mountains and the northern part of the Snake River
plain. This will bring G25KT to G30KT on the ridges in the
central Idaho mountains, and G25KT to locations like Rexburg and
Idaho Falls and the Arco Desert. Tuesday should be breezy to
windy once again.

For the extended period, either a partial breakdown of the upper
level ridge from a trough coming from the west or at least a
flattening of the ridge over Idaho should continue the not as
hot temperatures with dry westerly flow supressing showers and
thunderstorms, especially after Wed. 

&&

.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 1033 PM MDT Sat Aug 22 2026

It will be another round of TSRA developing 23/18Z-23/20Z for
all airdromes except one. KSUN appears to dry out to SKC before
convection can get going, and, at least for now, does not look
to be hampered by TSRA in the afternoon and evening. For the
rest, SPC has put them in an area of slight chance of severe
TSRA, so have outflow wind of 35G50KT for all of them during the
strength of afternoon heating. If the PROB30 group had to be
broken up due to increasing clouds, then the evening should not
be as strong, perhaps 30G45KT instead. CIGs stay above FL100
except in TSRA, but even then stays VFR. VSBYs could also be
reduce to marginal VFR, but only in a TSRA.

Final thing is the wind. KSUN, KIDA are both in areas where
gusty wind has been expected, so they have some SW wind of
15G25KT likely in the afternoon. KPIH is a close second with
sustained at 15KT. The other two KDIJ and KBYI should peak out
at around 10KT.

&&

.FIRE WEATHER...
Issued at 138 AM MDT Sun Aug 23 2026

Abundant lightning yesterday over receptive fuels had at least
several starts. The lightning show continues today, but in lower
coverage or probability of occurrence. Best coverage will be
along the WY border region of the Eastern Idaho Dispatch AoR.
Over a good portion of that Dispatch area and the Southern 
Idaho Dispatch area the expectations are few thunderstorms, but
much stronger in intensity, with solid chances of severe
strength thunderstorms in both regions. Much of the Central
Idaho dispatch area has only general thunderstorms, with the
eastern areas getting closer to the marginal risk of severe
storms. 

Cooler air has moved in, but this will be partially offset in
western areas by the strong sunshine with less cloudiness. Some
lower elevation areas will see humidity readings drop below 15
percent, but it is low elevations from Salmon to Challis where
that occurs, where wind will be somewhat lighter.

A low moving across the continent from west to east will
increase wind today for the central Idaho mountains and portions
of the Snake River plain. Critical fire weather conditions will
be very close in that Salmon to Challis corridor, but otherwise
not expecting anything close to critical. 

&&

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

&&

$$

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