Alert archive / Idaho / Severe Thunderstorm Warnings in 2020

Severe Thunderstorm Warning 30, NWS Pocatello, ID

July 23, 2020Fremont County, Madison County, Teton County, Idaho

NWS Pocatello, ID issued this severe thunderstorm warning at Jul 23, 2020, 5:36 PM MDT for Fremont County, Madison County, Teton County, Idaho. It was in force for 39 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
Jul 23, 2020, 5:36 PM MDT (23:36 UTC)
Expired
Jul 23, 2020, 6:15 PM MDT
In force
39 min
Issued by
NWS Pocatello, ID
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties Fremont County, ID, Madison County, ID, Teton County, ID

The radar

The Pocatello radar (KSFX), 135 km from the middle of the area, began a volume at 23:37 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, 11.6 hours before the alert went out and 352 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 2020-07-23Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 67 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 2020-07-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 176 square meters per square second.19395878Sfc1 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
67 J/kg
Mixed-layer CIN
-331 J/kg
Mixed-layer LCL
2027 m above ground
0-6 km bulk shear
34 kt
0-1 km storm-relative helicity
176 m²/s²
0-3 km storm-relative helicity
285 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

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 Jul 23, 1:52 PM MDT, 3 hours 44 minutes earlier.

Area forecast discussion, Jul 23, 1:52 PM MDT, 3 hours 44 minutes before
Area Forecast Discussion
National Weather Service Pocatello ID
152 PM MDT Thu Jul 23 2020

.DISCUSSION...A weak cold front will work into the area tonight.
Strong thunderstorms are possible just ahead of the front for the
remainder of the afternoon and into the evening with gusty winds
as the primary threat. Much of the activity will diminish after
sunset. Residual moisture lingers across the region Friday into
Saturday with high country thunderstorms possible during the
afternoon each day. Drier weather arrives for Sunday. But another
push of moisture arrives early next week bringing more
thunderstorms to the region.

13

&&

.AVIATION...Vicinity thunderstorms are in all TAF locations into
the evening although the better chances are around BYI and SUN,
closer to the front. Expect thunderstorms to diminish overnight.
Ceilings are likely to remain vfr except under thunderstorms.

13

&&

.FIRE WEATHER...Still looks like a good chance of Scattered to
Numerous showers and thunderstorms over the Central mountains
through this evening impacting mostly 475 and northern portions of
476 and 422. This is due to increased monsoon moisture as well as
instability from an approaching boundary/front. Since 422 looks to
be impacted mainly to the north of Sun Valley in elevations above
6000 ft, have held off on a Red Flag. Expect isolated thunderstorm
coverage in most of zone 422 below 6000 ft. Thunderstorms outside
the Central mountains are difficult to pin down due to model
inconsistency. There is some model consensus of a line of
thunderstorms developing outside of the Central mountains from Malad
to Mackay. This would support some scattered convection. However,
not all models show this line. Also, there is potential for more
rain in storms than yesterday. So showers and thunderstorms should
be more wet in nature than dry as precipitable water values have
risen. Storms today in the Central mountains and lower elevations
across our western areas (mainly 425) do have potential be gusty, up
to around 40 to 55 mph as well as produce hail. The clearer skies
today across our southwest areas will help support convective
activity as well this afternoon into early evening. Models continue
show less convective activity Friday. However, they do show isolated
coverage mainly in our Southwest, generally south of Burley/
Pocatello and the Island Park area. Saturday there again will be a
slight chance, though a lesser chance than Friday, of thunderstorms
over mainly our eastern mountain areas. Late Saturday into Sunday
expect overall drier conditions with a westerly breezy flow. Storm
chances pick back next week by Monday afternoon as the flow returns
to southwest versus west, and we pick up some more monsoon moisture
within the pattern. Wyatt

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
&&

In the hours before

Special weather statement, Jul 23, 3:14 PM MDT, 2 hours 22 minutes before
Special Weather Statement
National Weather Service Pocatello ID
314 PM MDT Thu Jul 23 2020

IDZ054-232215-
Lower Snake River Plain ID-
314 PM MDT Thu Jul 23 2020

...Thunderstorms near American Falls Reservoir...

At 313 PM MDT, Doppler radar was tracking thunderstorms near
American Falls, moving northeast at 15 mph.

Winds in excess of 30 mph and occasional lightning will be possible
with these storms.

Locations impacted include...
American Falls Reservoir.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If on or near American Falls Reservoir, Move to safe shelter now! Do
not be caught on or near the water. Gusty winds and choppy waves are
likely.

&&

LAT...LON 4275 11280 4280 11292 4308 11271 4297 11256
TIME...MOT...LOC 2113Z 213DEG 13KT 4282 11276

Valle
Special weather statement, Jul 23, 3:58 PM MDT, 1 hour 38 minutes before
Special Weather Statement
National Weather Service Pocatello ID
358 PM MDT Thu Jul 23 2020

IDZ053-054-058-062-232245-
Upper Snake River Plain ID-Marsh and Arbon Highlands ID-
Blackfoot Mountains ID-Lower Snake River Plain ID-
358 PM MDT Thu Jul 23 2020

...A STRONG THUNDERSTORM IS MOVING THROUGH CENTRAL BONNEVILLE AND
EAST CENTRAL BINGHAM COUNTIES...

At 357 PM MDT, Doppler radar was tracking a strong thunderstorm near
Fort Hall Lincoln Creek Lodge, or 8 miles southwest of Goshen, moving
northeast at 20 mph.

Dime size hail and winds in excess of 40 mph will be possible with
this storm.

Locations impacted include...
Goshen, Ammon, Bone, Fort Hall Lincoln Creek Lodge, Basalt and
Wapello.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

&&

LAT...LON 4312 11217 4322 11229 4347 11196 4341 11178
      4329 11174
TIME...MOT...LOC 2157Z 233DEG 18KT 4321 11215

TAX
Special weather statement, Jul 23, 4:13 PM MDT, 1 hour 23 minutes before
Special Weather Statement
National Weather Service Pocatello ID
413 PM MDT Thu Jul 23 2020

IDZ054-055-057-058-232315-
Eastern Magic Valley ID-Marsh and Arbon Highlands ID-
Raft River Region ID-Lower Snake River Plain ID-
413 PM MDT Thu Jul 23 2020

...ANOTHER ROUND OF THUNDERSTORMS WILL MOVE OVER AMERICAN FALLS
RESERVOIR CAUSING HAZARDOUS BOATING CONDITIONS...

At 410 PM MDT, Doppler radar was tracking a strong thunderstorm over
American Falls, moving northeast at 15 mph.

Winds in excess of 40 mph will be possible with this storm.

Locations impacted include...
American Falls, Neeley, American Falls Reservoir, Aberdeen, Pocatello
Airport and Sterling.

Boaters can expect a sudden increase in waves and very choppy waters
which will result in hazardous boating conditions. Boaters are urged
to seek safe harbor if possible.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If on or near American Falls Reservoir, move to safe shelter now! Do
not be caught on or near the water. Gusty winds and choppy waves are
likely.

Persons in campgrounds should consider seeking sturdy shelter until
this storm passes.

&&

LAT...LON 4270 11285 4275 11297 4308 11277 4305 11263
      4296 11250
TIME...MOT...LOC 2210Z 209DEG 15KT 4277 11285

TAX
Special weather statement, Jul 23, 4:30 PM MDT, 1 hour 6 minutes before
Special Weather Statement
National Weather Service Pocatello ID
430 PM MDT Thu Jul 23 2020

IDZ072-232315-
Sawtooth/Stanley Basin ID-
430 PM MDT Thu Jul 23 2020

...STRONG THUNDERSTORMS AND HEAVY RAIN NEAR STANLEY...

At 428 PM MDT, Doppler radar was tracking a strong thunderstorm 11
miles southwest of Stanley, moving northeast at 15 mph.

Half inch hail and winds in excess of 30 mph will be possible with
this storm.

Locations impacted include...
Stanley and Redfish Lake.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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.

Persons in campgrounds should consider seeking sturdy shelter until
this storm passes.

&&

LAT...LON 4441 11500 4424 11470 4402 11503 4403 11505
      4406 11505 4408 11502 4409 11500 4410 11500
      4410 11502 4412 11505 4415 11502 4416 11503
      4416 11506 4418 11508 4417 11511 4420 11516
TIME...MOT...LOC 2228Z 209DEG 14KT 4408 11508

TAX
Special weather statement, Jul 23, 5:10 PM MDT, 26 minutes before
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Local storm report, Jul 23, 5:21 PM MDT, 15 minutes before
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    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
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The office that day

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

IssuedProductOfficeCountiesLasted
Jul 23, 1:28 PM MDTSpecial Weather StatementPIHCuster32 min
Jul 23, 3:14 PM MDTSpecial Weather StatementPIHPower61 min
Jul 23, 3:58 PM MDTSpecial Weather StatementPIHBingham47 min
Jul 23, 4:13 PM MDTSpecial Weather StatementPIHPower62 min
Jul 23, 4:30 PM MDTSpecial Weather StatementPIHCuster45 min
Jul 23, 5:10 PM MDTSpecial Weather StatementPIHPower35 min
Jul 23, 5:58 PM MDTSpecial Weather StatementPIHPower47 min

Nearby

Severe Thunderstorm Warnings in Idaho, 2020Every severe thunderstorm warning in 2020

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.