Alert archive / Idaho / Severe Thunderstorm Warnings in 2026

Severe Thunderstorm Warning 52, NWS Pocatello, ID

September 17, 20265 counties in Idaho

NWS Pocatello, ID issued this severe thunderstorm warning at Sep 17, 2026, 4:16 PM MDT for 5 counties in Idaho. It was in force for 44 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Sep 17, 2026, 4:16 PM MDT (22:16 UTC)
Expired
Sep 17, 2026, 5:00 PM MDT
In force
44 min
Issued by
NWS Pocatello, ID
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties Bonneville County, ID, Clark County, ID, Fremont County, ID, Jefferson County, ID, Madison County, ID

The radar

The Pocatello radar (KSFX), 110 km from the middle of the area, began a volume at 22:17 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Salt Lake City I, UT (KSLC), launched 12:00Z, 10.3 hours before the alert went out and 347 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Salt Lake City I, UT at 12:00Z on 2026-09-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 339 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Salt Lake City I, UT at 12:00Z on 2026-09-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 59 square meters per square second.1939587897Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
339 J/kg
Mixed-layer CIN
-89 J/kg
Mixed-layer LCL
1793 m above ground
0-6 km bulk shear
31 kt
0-1 km storm-relative helicity
59 m²/s²
0-3 km storm-relative helicity
70 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Pocatello, ID wrote its last area forecast discussion before this severe thunderstorm warning went out at Sep 17, 12:52 PM MDT, 3 hours 24 minutes earlier. Its 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
Area forecast discussion, Sep 17, 12:52 PM MDT, 3 hours 24 minutes before
Area Forecast Discussion
National Weather Service Pocatello ID
1252 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 /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1250 PM MDT Thu Sep 17 2026

VFR conditions expected outside of any showers and thunderstorms.
Slow moving low pressure system will keep clouds and precipitation
in place through the period. Best thunderstorm potential will
continue through the evening but even some nocturnal storms remain
possible overnight with storms appearing likely again for Friday
afternoon. PROB30s continue for this afternoon with gusty winds
possible in and around thunderstorm outflows but synoptic winds are
expected to remain generally light. CIGs should stay high enough to
remain VFR with BKN/OVC coverage but again some localized, brief
reductions will be possible with storms.

&&

.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...
None.

&&

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

In the hours before

Local storm report, Sep 17, 2:08 PM MDT, 2 hours 8 minutes before
Preliminary Local Storm Report
National Weather Service Pocatello ID
208 PM MDT Thu Sep 17 2026

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

1245 PM     Non-Tstm Wnd Gst 2 ENE Fort Hall         43.03N 112.41W
09/17/2026  M46 MPH          Bingham            ID   Mesonet

            Mesonet station 8436 D5 Fort Hall I-15.

&&
Special weather statement, Sep 17, 3:16 PM MDT, 1 hour before
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Local storm report, Sep 17, 3:50 PM MDT, 26 minutes before
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Local storm report, Sep 17, 3:56 PM MDT, 20 minutes before
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Local storm report, Sep 17, 4:00 PM MDT, 16 minutes before
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Local storm report, Sep 17, 4:06 PM MDT, 10 minutes before
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The office that day

Everything else NWS Pocatello, ID issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 17, 12:09 AM MDTSpecial Weather StatementPIHOneida51 min
Sep 17, 12:46 AM MDTSpecial Weather StatementPIHPower29 min
Sep 17, 10:04 AM MDTFlash Flood Warning Considerable damage threatPIHJefferson, Madison3 hr
Sep 17, 1:47 PM MDTSevere Thunderstorm WarningPIHOneida, Power28 min
Sep 17, 1:50 PM MDTSpecial Weather StatementPIHMinidoka25 min
Sep 17, 1:52 PM MDTSpecial Weather StatementPIHBlaine23 min
Sep 17, 2:12 PM MDTSevere Thunderstorm WarningPIHBingham, Blaine, Butte33 min
Sep 17, 2:14 PM MDTSevere Thunderstorm WarningPIHBannock, Oneida, Power16 min
Sep 17, 2:29 PM MDTSevere Thunderstorm WarningPIHBingham, Blaine, Butte, Minidoka, Power46 min
Sep 17, 2:43 PM MDTSevere Thunderstorm WarningPIHBingham, Butte, Jefferson47 min
Sep 17, 3:16 PM MDTSpecial Weather StatementPIHBingham29 min
Sep 17, 3:28 PM MDTSevere Thunderstorm WarningPIHBingham, Bonneville, Butte, Jefferson62 min
Sep 17, 4:57 PM MDTSpecial Weather StatementPIHClark, Fremont48 min
Sep 17, 5:38 PM MDTSpecial Weather StatementPIHBingham37 min

Nearby

Severe Thunderstorm Warnings in Idaho, 2026Every severe thunderstorm warning in 2026

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.