Alert archive / Idaho / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 11, NWS Pocatello, ID

July 20, 2021Caribou County, Idaho

NWS Pocatello, ID issued this severe thunderstorm warning at Jul 20, 2021, 2:53 PM MDT for Caribou County, Idaho. It was in force for 37 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Jul 20, 2021, 2:53 PM MDT (20:53 UTC)
Expired: Jul 20, 2021, 3:30 PM MDT
In force: 37 min
Issued by: NWS Pocatello, ID
Area: Storm-based polygon
Hail: 1.0 in
Wind: 50.0 mph

County Caribou County, ID

The radar

The Pocatello radar (KSFX), 87 km from the middle of the area, began a volume at 20:56 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, 8.9 hours before the alert went out and 221 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 92 J/kg
Mixed-layer CIN: -127 J/kg
Mixed-layer LCL: 1787 m above ground
0-6 km bulk shear: 16 kt
0-1 km storm-relative helicity: 38 m²/s²
0-3 km storm-relative helicity: 38 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

619 
WUUS55 KPIH 202053
SVRPIH
IDC029-202130-
/O.NEW.KPIH.SV.W.0011.210720T2053Z-210720T2130Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Pocatello ID
253 PM MDT Tue Jul 20 2021

The National Weather Service in Pocatello has issued a

* Severe Thunderstorm Warning for...
  Central Caribou County in southeastern Idaho...

* Until 330 PM MDT.

* At 253 PM MDT, a severe thunderstorm was located 10 miles southeast
  of Chesterfield, or 10 miles northwest of Soda Springs, moving
  northeast at 30 mph.

  HAZARD...Quarter size hail.

  SOURCE...Radar indicated.

  IMPACT...Damage to vehicles is expected.

* Locations impacted include...
  Blackfoot Reservoir and Bancroft. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

Large hail and continuous cloud to ground lightning are occurring 
with this storm. Move indoors immediately.
Lightning is one of nature's leading killers. Remember, if you can
hear thunder, you are close enough to be struck by lightning.

&&

LAT...LON 4266 11181 4273 11193 4295 11165 4280 11144
TIME...MOT...LOC 2053Z 230DEG 28KT 4275 11175 

HAIL...1.00IN
WIND...<50MPH
 
$$

KSmith

2 follow-up statements

863 
WWUS55 KPIH 202110
SVSPIH

Severe Weather Statement
National Weather Service Pocatello ID
310 PM MDT Tue Jul 20 2021

IDC029-202130-
/O.CON.KPIH.SV.W.0011.000000T0000Z-210720T2130Z/
Caribou ID-
310 PM MDT Tue Jul 20 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 330 PM MDT
FOR CENTRAL CARIBOU COUNTY...

At 310 PM MDT, a severe thunderstorm was located near Blackfoot
Reservoir, moving northeast at 30 mph.

HAZARD...Quarter size hail.

SOURCE...Radar indicated.

IMPACT...Damage to vehicles is expected.

Locations impacted include...
Southern Blackfoot Reservoir.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

Continuous cloud to ground lightning is occurring with this storm.
Move indoors immediately. Lightning is one of nature's leading
killers. Remember, if you can hear thunder, you are close enough to
be struck by lightning.

&&

LAT...LON 4269 11178 4279 11185 4295 11165 4281 11146
TIME...MOT...LOC 2110Z 228DEG 26KT 4283 11164 

HAIL...1.00IN
WIND...<50MPH
 
$$

KSmith

782 
WWUS55 KPIH 202125
SVSPIH

Severe Weather Statement
National Weather Service Pocatello ID
325 PM MDT Tue Jul 20 2021

IDC029-202134-
/O.EXP.KPIH.SV.W.0011.000000T0000Z-210720T2130Z/
Caribou ID-
325 PM MDT Tue Jul 20 2021

...THE SEVERE THUNDERSTORM WARNING FOR CENTRAL CARIBOU COUNTY WILL
EXPIRE AT 330 PM MDT...
                
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning will be allowed to expire. The storm will 
continue to produce heavy downpours and lightning as it approaches 
Highway 34.

LAT...LON 4269 11178 4279 11185 4295 11165 4281 11146
TIME...MOT...LOC 2124Z 230DEG 28KT 4289 11154 

$$

KSmith

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 19, 7:32 PM MDT	Special Weather Statement	PIH	Bear Lake	43 min
Jul 20, 1:23 PM MDT	Special Weather Statement	PIH	Butte	67 min
Jul 20, 2:06 PM MDT	Special Weather Statement	PIH	Cassia	69 min
Jul 20, 2:16 PM MDT	Special Weather Statement	PIH	Power	44 min
Jul 20, 2:21 PM MDT	Special Weather Statement	PIH	Butte	54 min
Jul 20, 2:51 PM MDT	Special Weather Statement	PIH	Caribou	24 min
Jul 20, 3:35 PM MDT	Special Weather Statement	PIH	Bonneville	55 min
Jul 20, 4:09 PM MDT	Special Weather Statement	PIH	Caribou	36 min
Jul 20, 4:34 PM MDT	Special Weather Statement	PIH	Bonneville, Teton	56 min
Jul 20, 4:39 PM MDT	Special Weather Statement	PIH	Fremont, Madison	51 min
Jul 20, 4:41 PM MDT	Special Weather Statement	PIH	Caribou	34 min
Jul 20, 5:28 PM MDT	Special Weather Statement	PIH	Teton	32 min
Jul 20, 5:35 PM MDT	Special Weather Statement	PIH	Fremont	25 min

Nearby

Severe Thunderstorm Warnings in Idaho, 2021 Every severe thunderstorm warning in 2021

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.