Alert archive / Montana / Severe Thunderstorm Warnings in 2011

Severe Thunderstorm Warning 58, NWS Great Falls, MT

August 14, 20116 counties in Montana

NWS Great Falls, MT issued this severe thunderstorm warning at Aug 14, 2011, 10:35 PM MDT for 6 counties in Montana. It was in force for 40 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
Aug 14, 2011, 10:35 PM MDT (04:35 UTC)
Expired
Aug 14, 2011, 11:15 PM MDT
In force
40 min
Issued by
NWS Great Falls, MT
Area
Storm-based polygon

Counties Cascade County, MT, Chouteau County, MT, Hill County, MT, Liberty County, MT, Pondera County, MT, Teton County, MT

The radar

The Great Falls radar (KTFX), 69 km from the middle of the area, began a volume at 04:37 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

Great_falls, MT (KTFX), launched 00:00Z, 4.6 hours before the alert went out and 83 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 00:00Z on 2011-08-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.1000850700500300200100-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Great_falls, MT at 00:00Z on 2011-08-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 24 square meters per square second.1939Sfc1 km3 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
3913 m above ground
0-6 km bulk shear
4 kt
0-1 km storm-relative helicity
24 m²/s²
0-3 km storm-relative helicity
74 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 Great Falls, MT wrote its last area forecast discussion before this severe thunderstorm warning went out at Aug 14, 9:40 PM MDT, 55 minutes earlier.

Area forecast discussion, Aug 14, 9:40 PM MDT, 55 minutes before
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Hazardous weather outlook, Aug 14, 4:19 AM MDT, 18 hours 16 minutes before
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREAT FALLS MT
419 AM MDT SUN AUG 14 2011

MTZ008>015-044>055-151030-
BEAVERHEAD-NORTHERN ROCKY MOUNTAIN FRONT-EASTERN GLACIER-HILL-
CASCADE-CHOUTEAU-CENTRAL AND SOUTHERN LEWIS AND CLARK-MADISON-
TOOLE-LIBERTY-EASTERN PONDERA-BLAINE-
SOUTHERN ROCKY MOUNTAIN FRONT-EASTERN TETON-JUDITH BASIN-FERGUS-
JEFFERSON-BROADWATER-MEAGHER-GALLATIN-
419 AM MDT SUN AUG 14 2011

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL
MONTANA...NORTH CENTRAL MONTANA AND SOUTHWEST MONTANA.

.DAY ONE...TODAY AND TONIGHT

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.

In the hours before

Special weather statement, Aug 14, 8:57 PM MDT, 1 hour 38 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREAT FALLS MT
857 PM MDT SUN AUG 14 2011

MTZ012-150345-
CASCADE MT-MEAGHER MT-
857 PM MDT SUN AUG 14 2011

...SIGNIFICANT WEATHER ADVISORY FOR CENTRAL CASCADE COUNTIES UNTIL
945 PM MDT...

AT 855 PM...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
MODERATE THUNDERSTORM 13 MILES SOUTHEAST OF CASCADE...MOVING
NORTHEAST AT 25 MPH.

LOCATIONS NEAR THE PATH OF THE THUNDERSTORM INCLUDE
ULM...CASCADE...SAND COULEE AND GREAT FALLS.

HAIL UP TO A HALF INCH IN DIAMETER...WIND GUSTS TO 50 MPH AND BRIEF
HEAVY RAINFALL ARE POSSIBLE FROM THIS STORM.

LAT...LON 4763 11117 4716 11088 4698 11155 4727 11185
TIME...MOT...LOC 0257Z 223DEG 23KT 4712 11155
Local storm report, Aug 14, 9:41 PM MDT, 54 minutes before
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Local storm report, Aug 14, 9:52 PM MDT, 43 minutes before
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Special weather statement, Aug 14, 9:52 PM MDT, 43 minutes before
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Local storm report, Aug 14, 9:54 PM MDT, 41 minutes before
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Special weather statement, Aug 14, 10:24 PM MDT, 11 minutes before
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The office that day

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

IssuedProductOfficeCountiesLasted
Aug 14, 8:57 PM MDTSpecial Weather StatementTFXCascade48 min
Aug 14, 9:26 PM MDTRed Flag WarningTFXBlaine, Broadwater, Cascade, Chouteau, Fergus, Gallatin and 6 more24 hr
Aug 14, 9:52 PM MDTSpecial Weather StatementTFXCascade38 min
Aug 14, 10:24 PM MDTSpecial Weather StatementTFXJudith Basin51 min
Aug 14, 10:36 PM MDTSpecial Weather StatementTFXChouteau39 min
Aug 14, 11:14 PM MDTSpecial Weather StatementTFXHill46 min
Aug 15, 1:41 AM MDTSpecial Weather StatementTFXMadison49 min
Aug 15, 1:32 PM MDTSpecial Weather StatementTFXGallatin43 min
Aug 15, 3:00 PM MDTSpecial Weather StatementTFXBroadwater45 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; radar from the NEXRAD Level II archive.