937
FXUS65 KPIH 201202
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
602 AM MDT Mon Jul 20 2026

.KEY MESSAGES...

- Heat risk highest today, especially across the Magic Valley,
  Snake River Plain, and South Hills. Many low elevations will
  warm to around 100 degrees.

- Monsoon moisture increases beginning this evening. More
  widespread storms later evening through mid-week.

&&

.DISCUSSION...
Issued at 414 AM MDT Mon Jul 20 2026

Heat risk is at its peak today with HEAT ADVISORIES in effect for
much of Southeast Idaho from Noon today through 8 PM MDT this
evening for temperatures near or up to 100 degrees. Temperatures
will gradually cool through mid-week back to around normal to
slightly below normal.

Southwest flow will lift monsoonal moisture into Southeast Idaho
beginning this evening and will support daily shower and
thunderstorm chances through mid to late week. Isolated storms will
trend more scattered heading later into the week with locally heavy
rainfall and outflow winds of 40 to 50 mph. High resolution models
show activity primarily concentrated across central and south-
central Idaho during the evening with development further east
during the late night and overnight hours.

&&

.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 542 AM MDT Mon Jul 20 2026

Very little additions made to the forecast this TAF issuance.
Have kept VCSH at all sites beginning at 03z with no transition
to showers due to the dry nature of thunderstorms today.
Otherwise, expect increasing mid- to high- level clouds and
outflow winds ranging 40 to 50 mph.

&&

.FIRE WEATHER...
Issued at 414 AM MDT Mon Jul 20 2026

Excessive heat peaks today with many valley locations warming to
around 100 degrees, although heating could be inhibited in
areas where extensive cloud cover develops. Monsoonal moisture
will support daily shower and thunderstorm chances through mid
to late week. Isolated, mostly dry storms today will trend
wetter and more scattered heading later into the week with
locally heavy rainfall possible and outflow winds of 40 to 50
mph. High resolution models show activity primarily concentrated
across Fire Weather Zones 475 and 476 this evening with
development further east across 410 and 413 during the late
night and overnight hours. Widespread Min RH today will range 13
to 16 percent across Fire Weather Zones 410 and 425, but Min RH
will raise to 25 percent and higher beginning Tuesday as
monsoonal moisture lifts northward.

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
Heat Advisory from noon today to 8 PM MDT this evening for
IDZ051>059.

&&

$$

DISCUSSION...Cropp
AVIATION...Cropp
FIRE WEATHER...Cropp