Severe Thunderstorm Warning 55, NWS Pocatello, ID

Area Forecast Discussion
National Weather Service Pocatello ID
643 PM MDT Thu Sep 17 2026

.KEY MESSAGES...

- Showers and thunderstorms continue through Saturday

- Hail and gusty winds are possible with storms through this
  evening, and locally heavy rainfall through Saturday

- Cooler temperatures are expected through Saturday before
  slowly warming up next week

&&

.DISCUSSION...
Issued at 1250 PM MDT Thu Sep 17 2026

Showers and thunderstorms have continued today as one
of more waves spin north across Idaho ahead of the low centered over
northern California. Showers and storms already this morning have
produced moderate to heavy rainfall, as moisture continues to become
deeper and more conducive for this to happen. For the rest of today
and into this evening, more showers and storms will
develop...especially where the dry slot behind this morning's
precipitation has allowed for more sunshine to interact with the
humid airmass in place. Heavy rainfall at times is possible and will
be the main impact. Some stronger storms will produce hail and gusty
winds over 40 mph. The latter is already evident due to outflow from
storms over the eastern/southeast highlands, creating a slow moving
outflow boundary across the Snake Plain and into portions of the
Magic Valley. It is likely this boundary will become an additional
focus for storm development, in addition to anything from pure
heating. There is a MARGINAL RISK for severe storms across the area,
and certainly is possible with the conditions setting up.

The overall pattern remains unchanged through Saturday, as the
cutoff low over California is finally picked back up by the steering
flow across the rest of the western U.S. The low will still be a
slow mover, and finally shifts over the state on Saturday. Until
that low passes, expect multiple rounds of showers and storms
producing heavy rainfall at times. A combination of much higher
moisture content and more widespread showers and storms tomorrow
into Saturday, the potential for higher rainfall amounts has jumped
up quite a bit. Will everyone see the heaviest rainfall in the
forecast? No, but the potential is there and higher than the past
day or so. From the Wood River Valley south across the Magic Valley
and into the South Hills/Albion Mountains, potential rainfall
amounts through Saturday afternoon are the "lowest" and up to 0.35
is possible. Elsewhere, the potential is there from 0.50-1.0" with
locally higher amounts. The current storm total forecast is likely
showing the higher end of the forecast ranges, as likely not every
square mile shown in the gridded forecast is going to see those
amounts. We considered Flash Flood Watches especially in areas with
burn scars, but for now are opting to handle it on a case-by-case
basis in terms of any needed warnings.

Wraparound showers and storms are possible Sunday. Heading into next
week, there is a struggle on what happens with the next low moving
into the western U.S. Before it appeared the low would stay the
south and we would remain dry. There is some indication it may now
drift far enough north to bring some clouds and potentially more
showers and storms.  That seems to be handled by the Blend of Models
which does have isolated coverage daily across portions of central
and eastern Idaho. Temperatures will struggle to hit the 70s
tomorrow and Saturday, before warming back up early next week.

&&

.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 637 PM MDT Thu Sep 17 2026

Expect periods of showers and thunderstorms through Friday
afternoon. Went with prob 30 thunderstorms at all sites after
18Z Friday with -SHRA as well after 12Z or 18Z. Thunderstorms
at IDA and PIH should end after 02Z this evening.

&&

.FIRE WEATHER...
Issued at 1250 PM MDT Thu Sep 17 2026

A low pressure system moving through the region will produce
intermittent showers and thunderstorms over the next 36-48 hours.
Ample wetting rainfall is expected especially across the central
mountains and eastern highlands, with lower totals in the Magic
Valley and south Hills areas. This system will depart over the
weekend allowing for drier weather to setup by the second half of
the weekend and into much of next week.

&&

.PIH WATCHES/WARNINGS/ADVISORIES...

&&

DISCUSSION...Keyes
AVIATION...GK
FIRE WEATHER...McKaughan

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Special Weather Statement
National Weather Service Pocatello ID
614 PM MDT Thu Sep 17 2026

IDZ054-058-180045-
Marsh and Arbon Highlands ID-Lower Snake River Plain ID-
614 PM MDT Thu Sep 17 2026

...A STRONG THUNDERSTORM WILL IMPACT NORTH CENTRAL BANNOCK AND SOUTH
CENTRAL BINGHAM COUNTIES THROUGH 645 PM MDT...

At 614 PM MDT, Doppler radar was tracking a strong thunderstorm over
Fort Hall Buffalo Lodge, or 10 miles north of Pocatello, moving
northeast at 15 to 20 mph.

HAZARD...Wind gusts in excess of 35 mph and nickel size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor hail damage to outdoor objects is
         possible.

Locations impacted include...
Blackfoot, Chubbuck, Fort Hall Buffalo Lodge, Fort Hall Eagle Lodge,
and Fort Hall Townsite.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4290 11251 4303 11255 4320 11235 4307 11223
TIME...MOT...LOC 0014Z 228DEG 19KT 4302 11247

MAX HAIL SIZE...0.88 IN
MAX WIND GUST...35 MPH

TW

Preliminary Local Storm Report
National Weather Service Pocatello ID
617 PM MDT Thu Sep 17 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0545 PM     Hail             1 SSE Pocatello Airport 42.90N 112.59W
09/17/2026  M0.75 Inch       Power              ID   Official NWS Obs

&&

Special Weather Statement
National Weather Service Pocatello ID
752 PM MDT Thu Sep 17 2026

IDZ052-053-067-180245-
Arco/Mud Lake Desert ID-Upper Snake River Plain ID-
Beaverhead/Lemhi Highlands ID-
752 PM MDT Thu Sep 17 2026

...A STRONG THUNDERSTORM WILL IMPACT SOUTHWESTERN FREMONT...CENTRAL
JEFFERSON...NORTHERN BONNEVILLE...NORTHWESTERN MADISON AND EAST
CENTRAL CLARK COUNTIES THROUGH 845 PM MDT...

At 751 PM MDT, Doppler radar was tracking a strong thunderstorm 7
miles southwest of Roberts, or 13 miles northwest of Idaho Falls,
moving snortheast at 25 mph.

HAZARD...Wind gusts in excess of 45 mph and nickel size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor hail damage to outdoor objects is
         possible.

Locations impacted include...
Rexburg, Sugar City, Menan, Roberts, Lewisville, Parker, Egin, Plano,
St Anthony, Osgood, Saint Anthony Sand Dunes, and Sage Junction.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 4417 11193 4401 11160 4349 11216 4362 11240
TIME...MOT...LOC 0151Z 027DEG 22KT 4364 11222

MAX HAIL SIZE...0.88 IN
MAX WIND GUST...45 MPH

GK

Special Weather Statement
National Weather Service Pocatello ID
825 PM MDT Thu Sep 17 2026

IDZ052>054-180315-
Arco/Mud Lake Desert ID-Upper Snake River Plain ID-
Lower Snake River Plain ID-
825 PM MDT Thu Sep 17 2026

...A STRONG THUNDERSTORM WILL IMPACT SOUTHWESTERN JEFFERSON...
NORTHWESTERN BANNOCK...WESTERN BONNEVILLE AND WESTERN BINGHAM
COUNTIES THROUGH 915 PM MDT...

At 824 PM MDT, Doppler radar was tracking a strong thunderstorm 8
miles southwest of Taber, or 19 miles west of Blackfoot, moving
northeast at 25 mph.

HAZARD...Wind gusts in excess of 35 mph and nickel size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor hail damage to outdoor objects is
         possible.

Locations impacted include...
Blackfoot, eastern American Falls Reservoir, Firth, Rose, Fort Hall
Eagle Lodge, Taber, Springfield, Rockford, Moreland, Pingree,
Groveland, Basalt, Sterling, East Butte, and Wapello.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 4365 11258 4329 11209 4293 11272 4323 11289
TIME...MOT...LOC 0224Z 197DEG 22KT 4322 11272

MAX HAIL SIZE...0.88 IN
MAX WIND GUST...35 MPH

GK

Preliminary Local Storm Report
National Weather Service Pocatello ID
918 PM MDT Thu Sep 17 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0900 PM     Hail             1 E Blackfoot           43.19N 112.33W
09/17/2026  E1.50 Inch       Bingham            ID   Public

&&