Alert archive / Montana / Severe Thunderstorm Warnings in 1997

Severe Thunderstorm Warning 59, NWS Great Falls, MT

August 7, 1997Pondera County, Montana

NWS Great Falls, MT issued this severe thunderstorm warning at Aug 7, 1997, 4:34 PM MDT for Pondera County, Montana. It was in force for 56 min. 1 report came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued
Aug 7, 1997, 4:34 PM MDT (22:34 UTC)
Expired
Aug 7, 1997, 5:30 PM MDT
In force
56 min
Issued by
NWS Great Falls, MT
Area
Whole counties

County Pondera County, MT

The radar

The Great Falls radar (KTFX), 106 km from the middle of the area, began a volume at 22:34 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.

What was reported inside it

TimeReportWhereRemark
Aug 7, 5:10 PM MDTHail 2Valier, MT

NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in.

The nearest sounding before it

Great_falls, MT (KTFX), launched 12:00Z, 10.6 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 1997-08-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 151 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, Great_falls, MT at 12:00Z on 1997-08-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 92 square meters per square second.1939Sfc1 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
151 J/kg
Mixed-layer CIN
-192 J/kg
Mixed-layer LCL
2429 m above ground
0-6 km bulk shear
18 kt
0-1 km storm-relative helicity
92 m²/s²
0-3 km storm-relative helicity
70 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KGTF 072235 RRA
SVRGTF
MTC073-072330-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE GREAT FALLS MT
434 PM MDT THU AUG 7 1997
 
THE NATIONAL WEATHER SERVICE IN GREAT FALLS HAS ISSUED A
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL  530 PM MDT
FOR PEOPLE IN THE FOLLOWING LOCATION...
 
IN NORTH MONTANA
 
   ...PONDERA COUNTY
 
AT 430 PM...WEATHER RADAR INDICATED A SEVERE THUNDERSTORM OVER WESTERN
PONDERA COUNTY NEAR HEART BUTTE. THIS STORM WAS MOVING EAST AT 30 MPH.
IT WILL BE MOVING TO NEAR CONRAD BY 530 PM. LARGE HAIL...STRONG WINDS...
HEAVY RAIN AND DANGEROUS LIGHTNING ARE LIKELY WITH THIS STORM.

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 7, 1:41 PM MDTSevere Thunderstorm WarningTFXCascade49 min
Aug 7, 4:09 PM MDTSevere Thunderstorm WarningTFXCascade36 min
Aug 7, 4:46 PM MDTSevere Thunderstorm WarningTFXCascade59 min

Nearby

Severe Thunderstorm Warnings in Montana, 1997Every severe thunderstorm warning in 1997

Sources

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