Alert archive / Montana / Severe Thunderstorm Warnings in 2011

Severe Thunderstorm Warning 21, NWS Great Falls, MT

July 7, 2011Fergus County, Montana

NWS Great Falls, MT issued this severe thunderstorm warning at Jul 7, 2011, 1:53 PM MDT for Fergus County, Montana. It was in force for 41 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 7, 2011, 1:53 PM MDT (19:53 UTC)
Expired
Jul 7, 2011, 2:34 PM MDT
In force
41 min
Issued by
NWS Great Falls, MT
Area
Storm-based polygon

County Fergus County, MT

The nearest sounding before it

Great_falls, MT (KTFX), launched 12:00Z, 7.9 hours before the alert went out and 148 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, Great_falls, MT at 12:00Z on 2011-07-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 874 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Great_falls, MT at 12:00Z on 2011-07-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 4 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
874 J/kg
Mixed-layer CIN
-164 J/kg
Mixed-layer LCL
1766 m above ground
0-6 km bulk shear
29 kt
0-1 km storm-relative helicity
4 m²/s²
0-3 km storm-relative helicity
55 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.1

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

675 
WUUS55 KTFX 071953
SVRTFX
MTC027-072100-
/O.NEW.KTFX.SV.W.0021.110707T1953Z-110707T2100Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE GREAT FALLS MT
153 PM MDT THU JUL 7 2011

THE NATIONAL WEATHER SERVICE IN GREAT FALLS HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTH CENTRAL FERGUS COUNTY IN CENTRAL MONTANA...

* UNTIL 300 PM MDT

* AT 147 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM 16 MILES SOUTH OF LEWISTOWN...MOVING EAST AT 20
  MPH.

* THE SEVERE THUNDERSTORM WILL GENERALLY REMAIN OVER RURAL AREAS
  OF SOUTH CENTRAL FERGUS COUNTY NEAR THE BIG AND LITTLE SNOWY 
  MOUNTAINS INCLUDING THE HALF MOON PASS AREA.

HAIL TO THE SIZE OF QUARTERS AND WIND GUSTS TO 60 MPH ARE LIKELY WITH
THIS STORM.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

&&

LAT...LON 4682 10862 4675 10861 4674 10863 4675 10938
      4673 10939 4674 10945 4693 10945 4699 10860
      4699 10859 4689 10859 4684 10860
TIME...MOT...LOC 1952Z 274DEG 19KT 4684 10934

$$

HOENISCH
1 follow-up statement
457 
WWUS55 KTFX 072034
SVSTFX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREAT FALLS MT
234 PM MDT THU JUL 7 2011

MTC027-072044-
/O.CAN.KTFX.SV.W.0021.000000T0000Z-110707T2100Z/
FERGUS MT-
234 PM MDT THU JUL 7 2011

...THE SEVERE THUNDERSTORM WARNING FOR SOUTH CENTRAL FERGUS COUNTY IS
CANCELLED...

NATIONAL WEATHER SERVICE RADAR INDICATED THAT THE SEVERE THUNDERSTORM
THAT PROMPTED THE WARNING HAD WEAKENED AND WAS NO LONGER SEVERE...
THUS THE WARNING HAS BEEN CANCELLED.

LAT...LON 4682 10862 4675 10861 4674 10863 4675 10938
      4673 10939 4674 10945 4693 10945 4699 10860
      4699 10859 4689 10859 4684 10860
TIME...MOT...LOC 2034Z 274DEG 19KT 4682 10902

$$

SUK

The office that day

Everything else NWS Great Falls, MT issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 7, 7:47 AM MDTSpecial Weather StatementTFXFergus43 min
Jul 7, 8:47 AM MDTSpecial Weather StatementTFXPetroleum43 min
Jul 7, 9:32 AM MDTSevere Thunderstorm WarningTFXFergus30 min
Jul 7, 11:59 AM MDTSpecial Weather StatementTFXJudith Basin46 min
Jul 7, 12:39 PM MDTSpecial Weather StatementTFXWheatland51 min
Jul 7, 1:33 PM MDTSpecial Weather StatementTFXFergus72 min
Jul 7, 2:39 PM MDTSpecial Weather StatementTFXWheatland51 min
Jul 7, 2:56 PM MDTFlash Flood WarningTFXFergus, Judith Basin3 hr
Jul 7, 2:57 PM MDTHigh Wind WarningTFX36 hr
Jul 7, 3:51 PM MDTSpecial Weather StatementTFXBlaine54 min
Jul 7, 5:11 PM MDTAreal Flood WarningTFXMadison35 min
Jul 7, 5:37 PM MDTSpecial Weather StatementTFXBlaine53 min

Nearby

Severe Thunderstorm Warnings in Montana, 2011Every severe thunderstorm warning in 2011

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.