613
FXUS65 KPIH 301045
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
445 AM MDT Mon Jun 30 2025

.KEY MESSAGES...

- Above normal temperatures will continue throughout the week,
  peaking today through Wednesday, with highs reaching the
  upper 80s to upper 90s in the valleys.

- Daily shower and thunderstorm chances return midweek as
  monsoonal moisture lifts north into southeast Idaho.

&&

.SHORT TERM /THROUGH TUESDAY/...
Issued at 144 AM MDT Mon Jun 30 2025

The heat will be the big story the next few days as the warmest
temps so far this summer move in to eastern Idaho. High pressure
remains in firm control of the weather and early morning satellite
imagery is void of any appreciable cloud cover and this is expected
to continue throughout the day today as temperatures will climb well
into the 90s across many of our lower valleys. Winds will remain
light with high pressure in place. Hi-res CAMs do show some
potential for shower/storm development in and around the South Hills
late this afternoon and into the early evening. The atmosphere
appears too dry for any precip to reach the surface so these will
likely be of the dry variety but could kick out some breezy outflow
winds. The hottest day of the week ahead will certainly be on
Tuesday as some triple digit heat isn`t out of the question. Most
areas in our lower valleys will top out in the mid to upper 90s
under mostly clear skies but a few spots could top the century mark
as supported by about 20% of available model ensemble members.
Regardless of whether we get that warm, it`ll certainly be very warm
and we remain concerned about the need for heat related
headlines. Overnight lows are cooling just enough in the
forecast to make the decision on an advisory just a bit more
difficult but a decision will have to be made later this
afternoon. Will likely see some showers and thunderstorms
develop across the higher terrain of the central mountains and
along the Montana Divide as we get into the afternoon/evening
hours on Tuesday.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
Issued at 144 AM MDT Mon Jun 30 2025

This diurnal shower/thunderstorm trend looks to continue for the
rest of the workweek and into holiday weekend as the upper level
pattern becomes more supportive of a bit more unsettled weather. An
upper low moving in to central California on Wednesday turns the
upper flow more southerly across our area allowing for a bit more
moisture to sneak in, increasing cloud cover, lowering temps a touch
and bringing PoPs back in to the forecast. Wednesday still looks
very warm though with low to mid 90s expected in the afternoon
across lower elevations but things return back into the 80s from
Thursday through Saturday. Best precip chances each day will
probably be focused across the higher terrain but with a series of
weak shortwaves moving through the broad U/L trough across the
region, things will remain active to into the holiday weekend with
some isolated PoPs even in the valley not out of the question.

&&

.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 442 AM MDT Mon Jun 30 2025

High pressure is keeping skies SKC/CLR and VSBY unlimited. By
this afternoon some moisture coming in from the south will
produce FEW-SCT mid- to high-level cloudiness, with some
possible BKN CIGs at that altitude. High pressure is also
keeping wind light at every airdrome, with some slope-valley
influence shown at some airports, while others are mostly light
and variable.

&&

.FIRE WEATHER...
Issued at 144 AM MDT Mon Jun 30 2025

Warming and drying continue into Tuesday, but a wind shift aloft
will bring in the remnants of a southwest monsoon, even as early as
this evening in the southern end of the Sawtooth NF. By Tue, the
more humid, more unstable air will push northward all the way to the
Montana border in the Salmon-Challis NF. By Wed, then lasting
through the entire holiday weekend, the thunderstorm threat will
have spread to the entire forecast area, even the Snake River plain
and eastern Magic Valley by Thu. The vast bulk of the thunderstorm
activity appears to be dry (below 0.10 of an inch accumulation)

The incoming air mass will help increase humidity, keeping afternoon
minima above critical thresholds. Wind is expected to increase, but
not significantly unless struck by a thunderstorm.

Temperatures peak Tue, are down slightly thanks to cloud cover on
Wed, then cool strongly for Thu, with low elevation temperatures in
the 80s which continues through Sat. Sun starts to see an increase
as the upper level winds start to shift away from the south.

&&

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

&&

$$

SHORT TERM...McKaughan
LONG TERM...McKaughan
AVIATION...Messick
FIRE WEATHER...Messick