219
FXUS65 KPIH 141130
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
530 AM MDT Mon Jul 14 2025

.KEY MESSAGES...

- Shortwave trough passage today leading to isolated showers and
  wet/dry thunderstorms, breezy winds, and near critical to
  critical fire weather conditions.

- Cold front later in the day Tuesday will support another
  round of isolated to scattered showers and wet/dry
  thunderstorms along with breezy winds.

- Cooler and drier airmass shifts into place on Wednesday.

- Warmer and drier conditions favored to finish out the week.

&&

.SHORT TERM /THROUGH TUESDAY NIGHT/...
Issued at 230 AM MDT Mon Jul 14 2025

Early morning satellite imagery shows a shortwave trough
working east along the Montana Divide, as isolated showers and
thunderstorms continue up around Clark and Fremont Counties.
Behind this departing trough later this morning, a secondary
shortwave will build in out of the west this afternoon/evening,
supporting another round of breezy winds and isolated to
scattered showers and thunderstorms. The HREF model probability
of thunder today shows two main active corridors of convection
this afternoon and evening. The primary being a 40-80% chance in
the Central Mountains east across the Upper Snake River Plain,
Montana Divide, and Eastern Highlands, with a secondary along
20-40% area along the Idaho-Nevada border region through the
Owyhees east into the South Hills/Albion Mountains region. Given
a very dry environment in place at the surface, we will see a
mix of showers/virga and wet/dry thunderstorms given PWATs in
that 0.50-0.80" range. The primary hazards with stronger
thunderstorms today will center around wind gusts up to 50 mph,
small hail, and brief rain. Synoptic winds will also remain
breezy this afternoon as well, with gusts peaking around 25-35
mph outside of any thunderstorms. Given elevated winds and low
relative humidity, elevated to critical fire weather conditions
will be possible today. More on that in the Fire Weather
discussion below. Highs today will remain above normal with
highs in the 80s/90s.

Behind that departing shortwave trough this evening, attention
quickly turns to a compact mid/upper-level low diving southeast
out of British Columbia, working southeast across the Idaho
Panhandle and Western Montana Tuesday/Tuesday night. This system
will drive a cold front across southern Idaho later in the day
Tuesday, with isolated to scattered showers and thunderstorms
expected regionwide. Outside of very isolated activity Tuesday
morning, best chances for showers and storms will be during the
afternoon/evening hours with a 15-30% chance regionwide, locally
higher in that 30-80% range in the Eastern Highlands and along
the Montana Divide. Stronger storms will be capable of producing
wind gusts up to 55 mph, small hail, and brief moderate to
heavy rain. We will again see a mix of virga, showers, and
wet/dry thunderstorms along this front given a dry surface
environment in place. Winds outside of any convection will
remain breezy, with gusts Tuesday afternoon peaking around 25-40
mph. Shower and thunderstorm activity will wind down after
sunset as isolated chances persist along the Montana and Wyoming
border regions for Tuesday night. Increased cloud cover and
moisture may shave a couple of degrees off of high temperatures
in some areas, but aside from the northern Central Mountains
east along the Montana border, highs will remain similar to
Monday in the 80s/90s.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
Issued at 230 AM MDT Mon Jul 14 2025

A cooler and drier airmass will move into place on Wednesday
behind an exiting upper-level trough and cold front east over
the Continental Divide. Highs will be around 5-10 degrees cooler
than Tuesday in the 70s/80s with lighter winds expected
regionwide as gusts remain less than 30 mph. Weak moisture
transport along the Montana Divide behind this exiting system
will lead to a 10-20% chance of showers and thunderstorms up in
the Eastern Highlands throughout the day as conditions remain
predominantly dry elsewhere. This cool-down looks to short-lived
however as prevailing W/SW flow will lead to warmer
temperatures to finish out the week with highs back in the
80s/90s each day. A series of shortwave troughs propagating
through southern Idaho later in the week may help to support
some isolated showers and thunderstorms primarily in the
mountains, but conditions are expected to remain dry overall
heading into early next week. These troughs may tap into the
northern extent of a monsoonal moisture plume to our south,
however the latest ensemble model guidance still keeps any
activity isolated in nature.

&&

.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 530 AM MDT Mon Jul 14 2025

Predominant VFR and dry conditions will continue for Monday as a
shortwave trough passes overhead this afternoon and evening,
supporting breezy winds and isolated showers and thunderstorms.
Have included a PROB30 group for -TSRA and wind gusts up to 35
kts for KIDA and KDIJ where best chances for gusty thunderstorm
outflow winds are expected. Wind gusts today will peak around
15-25 kts this afternoon outside of any convection. Behind this
exiting trough tonight, dry conditions and lighter winds will
return overnight as very isolated showers remain possible.

&&

.FIRE WEATHER...
Issued at 230 AM MDT Mon Jul 14 2025

Hot and mostly dry conditions will continue today as a
shortwave trough works east across southern Idaho, leading to
breezy winds and isolated virga/showers and wet/dry
thunderstorms this afternoon and evening. Best shower and
thunderstorm chances will exist in the Central Mountains east
across the Upper Snake River Plain into the Eastern Highlands,
with stronger thunderstorms capable of producing wind gusts up
to 50 mph, small hail, and brief rain. Synoptic winds will also
remain elevated this afternoon as well, with gusts peaking
around 25-35 mph outside of any thunderstorms. Due to a
combination of low relative humidity and gusty winds, a Fire
Weather Watch remains in effect from 1400 to 2100 MDT today for
FWZ 425 and 427 where critical fire weather conditions are
expected. Near critical to critical fire weather conditions will
remain possible in FWZ 410 and 413, but have held off on any
headlines at this time. The FWW will need to be upgraded later
today with a potential expansion further east to FWZ 410 and 413
dependent on partner coordination. MinRHs this afternoon will
drop to the teens/20s regionwide.

Behind this exiting shortwave tonight, attention turns to a
more organized system working southeast of British Columbia
along the Continental Divide for Tuesday into Tuesday night as a
cold front tracks over southern Idaho later in the day Tuesday.
This system will lead to a mix of isolated to scattered
virga/showers and wet/dry thunderstorms regionwide, along with
keeping winds elevated with synoptic gusts peaking around 25-40
mph. MinRHs in the afternoon hours will again be in the
teens/20s, leading to elevated to near critical fire weather
conditions. Stronger storms on Tuesday will be capable of
producing wind gusts up to 55 mph, small hail, and brief
moderate to heavy rain. Coverage of showers and storms will peak
in the afternoon and evening hours, as drier conditions build
in out of the west for Tuesday night.

A cooler and drier airmass will shift into place on Wednesday
as winds lessen, highs cool about 5-10 degrees, and isolated
showers and storms shift to being confined to Eastern Highlands
and Upper Snake River Plain. This cool-down looks to short-lived
however as prevailing W/SW flow will lead to warmer
temperatures to finish out the week with highs back in the
80s/90s and MinRHs in the teens/20s each day. A series of
shortwave troughs propagating through southern Idaho later in
the week may help to support some isolated showers and
thunderstorms primarily in the mountains, but conditions are
expected to remain dry overall heading into early next week.
These troughs may tap into the northern extent of a monsoonal
moisture plume to our south, however the latest ensemble model
guidance still keeps any activity isolated in nature.

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
Fire Weather Watch from 2 PM MDT this afternoon through this
evening for IDZ425-427.

&&

$$

SHORT TERM...MacKay
LONG TERM...MacKay
AVIATION...MacKay
FIRE WEATHER...MacKay