972
FXUS65 KPIH 151100
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
500 AM MDT Tue Jul 15 2025

.KEY MESSAGES...

- Cold front later today will support isolated to scattered
  thunderstorms, breezy winds, and near critical to critical
  fire weather conditions.

- Isolated strong to severe thunderstorms will be possible this
  afternoon and evening, capable of producing wind gusts up to
  around 50-60 mph, up to 1-1.5" diameter sized hail, moderate
  to heavy rain, and frequent lightning.

- Cooler and drier conditions on Wednesday.

- Warming trend to finish out the week with any shower and
  thunderstorm development remaining isolated.

&&

.SHORT TERM /THROUGH WEDNESDAY NIGHT/...
Issued at 245 AM MDT Tue Jul 15 2025

Early morning satellite imagery shows a closed mid/upper-level
low diving southeast out of British Columbia, tracking southeast
into the Idaho Panhandle and Western Montana. As this trough
works east through Montana throughout the day, a cold front this
afternoon and evening will support another round of isolated to
scattered shower and thunderstorm development along with breezy
winds. Out ahead of this front, isolated showers will remain
possible this morning ahead of convective initiation this
afternoon and evening. For later today, we are looking at two
main areas for stronger storms: one in the east-Central
Mountains across the Upper Snake River Plain and Eastern
Highlands starting first and a secondary area southeast of the
Snake River Plain south into Utah starting second. These areas
are where the HREF model probability of winds greater than 35
mph shows a 70-90%+ chance, including a 10-30% chance of winds
greater than 58 mph southeast of the Snake River Plain.

Given today`s ensemble convective environment supporting
500-1000 J/kg of MUCAPE, 25-40 kts of 0-6 km shear (pushing
40-50 kts further north), and 6-10 degree/km 700-500 mb lapse
rates, isolated to scattered strong to severe thunderstorms are
expected this afternoon and evening. As evident by stronger
thunderstorms yesterday out across the Shoshone/Arco/Mud Lake
Desert and South Hills/Raft River Valley regions producing wind
gusts of 45-65 mph, strong to severe storms today will be
capable of producing wind gusts up to 50-70 mph, up to 1-1.5"
diameter sized hail, moderate to heavy rain, and frequent
lightning. Given this increasing confidence, the Storm
Prediction Center has expanded their Marginal Risk (5-14%
chance) of severe thunderstorms today to include everywhere
outside the west- Central Mountains and western Magic Valley.
Stay tuned for additional forecast information, warnings, and
alerts later today as we track this thunderstorm development. We
will also see a mix of wet and dry thunderstorms today which
coupled with scattered coverage, has prompted a Red Flag Warning
for Idaho FWZ 410/411/413/427 from 12-9 PM MDT today. More on
that in the Fire Weather Discussion below. Behind the cold
frontal passage tonight, showers and storms will become
increasingly isolated after midnight and shift east ahead of dry
conditions back regionwide for Wednesday. Precipitation totals
today will range from a T-0.25" for most, locally higher in that
0.25-1.00" range where stronger thunderstorms pass over. Highs
today will be in the 80s/90s as synoptic winds outside of any
convection will support gusts peaking around 25-45 mph this
afternoon.

Wednesday is shaping up to cooler and drier with lighter winds
overall behind the cold front, as zonal flow fills in behind the
exiting boundary. This will lead to highs in the 70s/80s (90s
further south) with wind gusts peaking around 15-25 mph. The
forecast for tomorrow has also trended drier, with less than a
10% chance of any shower and thunderstorm development during the
daytime hours Wednesday into Wednesday night. |

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
Issued at 245 AM MDT Tue Jul 15 2025

Near normal to above normal temperatures and mostly dry
conditions will prevail throughout the long term period as W/SW
flow dominates the overall mid/upper-level flow pattern. A
series of shortwave troughs later this week into early next week
will help trigger a 5- 20% chance of afternoon showers and
thunderstorms each day (primarily in the mountains), as
conditions remain very dry overall outside of any of this
isolated activity. As of the latest ensemble model guidance,
coverage of these showers and storms will peak on Friday and
Saturday, with very isolated coverage expected other days. Highs
each day will be in the 80s/90s in the valleys with breezy
winds expected each afternoon, supporting gusts up to around
20-40 mph. A combination of breezy winds and low relative
humidity will need to be monitored later this week for any
overlap for Red Flag Warning criteria. More on that in the Fire
Weather Discussion below.

&&

.AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/...
Issued at 500 AM MDT Tue Jul 15 2025

Predominant VFR and dry conditions under mostly clear skies
will continue this morning, ahead of a cold front building in
this afternoon/evening with breezy winds and isolated/scattered
showers and thunderstorms. A PROB30 group has been introduced
at KPIH, KIDA, and KDIJ to highlight the best timing for
thunderstorms moving on station, with KPIH and KIDA seeing a
20-30% chance of thunderstorms and KDIJ seeing a 30-50% chance.
KSUN and KBYI currently have less than a 20% chance at each
terminal so have not included anything there, but will continue
to monitor trends later today, especially around the Magic
Valley and Snake River Plain. Dry conditions, lighter winds, and
clear skies will return overnight tonight into Wednesday.

&&

.FIRE WEATHER...
Issued at 245 AM MDT Tue Jul 15 2025

Today will be another critical fire weather day across eastern
Idaho as a cold front passes overhead later in the day,
supporting gusty winds, low RH, and isolated to scattered
thunderstorms. Aside from isolated showers this morning,
convective initiation will begin around 12-3 PM and continue
through 9 PM to midnight, ahead of dry conditions back for
Wednesday. As evident by stronger thunderstorms yesterday out
across the Shoshone/Arco/Mud Lake Desert and South Hills/Raft
River Valley regions producing wind gusts of 45-65 mph, strong
to severe storms today will be capable of producing wind gusts
up to 60-70 mph, 1-1.5" diameter sized hail, moderate to heavy
rain, and frequent lightning. While most thunderstorms will
remain wet, we will also see isolated dry thunderstorms at times
as well. As a result, a Red Flag Warning remains in effect for
Idaho FWZ 410/411/413/427 today with elevated to near critical
fire weather conditions expected regionwide due to a combination
of gusty winds and low RH in the teens/20s. Highs today will be
in the 80s/90s as synoptic winds outside of any convection will
support gusts peaking around 25-45 mph this afternoon.

Wednesday is shaping up to cooler and drier with lighter winds
overall behind the cold front, as zonal flow fills in behind the
exiting boundary. This will lead to highs in the 70s/80s (90s
further south) with wind gusts peaking around 15-25 mph. The
forecast for tomorrow has also trended drier, with less than a
10% chance of any shower and thunderstorm development during the
daytime hours Wednesday into Wednesday night.

Looking ahead towards later this week into early next week,
near normal to above normal temperatures and mostly dry
conditions will prevail as W/SW flow dominates the overall
mid/upper-level flow pattern. A series of shortwave troughs
during this timeframe will help trigger a 5-20% chance of
afternoon showers and thunderstorms (primarily in the mountains)
each day, as conditions remain very dry overall outside of any
of this isolated activity. As of the latest ensemble model
guidance, coverage of these showers and storms will peak on
Friday and Saturday, with very isolated coverage expected other
days. Highs each day will be in the 80s/90s in the valleys with
breezy winds expected each afternoon, supporting gusts up to
around 20-40 mph. A combination of breezy winds and low relative
humidity will need to be monitored later this week for any
overlap for Red Flag Warning criteria. Stay tuned.

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning from noon today to 9 PM MDT this evening for
IDZ410-411-413-427.

&&

$$

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