Alert archive / Montana / Severe Thunderstorm Warnings in 1997

Severe Thunderstorm Warning 39, NWS Great Falls, MT

July 6, 1997Chouteau County, Montana

NWS Great Falls, MT issued this severe thunderstorm warning at Jul 6, 1997, 5:30 PM MDT for Chouteau County, Montana. It was in force for 45 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 6, 1997, 5:30 PM MDT (23:30 UTC)
Expired
Jul 6, 1997, 6:15 PM MDT
In force
45 min
Issued by
NWS Great Falls, MT
Area
Whole counties

County Chouteau County, MT

The radar

The Great Falls radar (KTFX), 85 km from the middle of the area, began a volume at 23:32 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 12:00Z, 11.5 hours before the alert went out and 48 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 1997-07-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 26 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 1997-07-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 67 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
26 J/kg
Mixed-layer CIN
-297 J/kg
Mixed-layer LCL
2153 m above ground
0-6 km bulk shear
35 kt
0-1 km storm-relative helicity
67 m²/s²
0-3 km storm-relative helicity
85 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 062330 RRA
SVRGTF
MTC015-070015-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE GREAT FALLS MT
530 PM MDT SUN JUL 6 1997
 
THE NATIONAL WEATHER SERVICE IN GREAT FALLS HAS ISSUED A
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL  615 PM MDT
FOR PEOPLE IN THE FOLLOWING LOCATION...
 
IN NORTH CENTRAL MONTANA
 
   ...EASTERN CHOUTEAU COUNTY
 
AT 530 PM...RADAR INDICATED A SEVERE THUNDERSTORM 15 MILES SOUTHEAST OF
BIG SANDY...OR 40 MILES SOUTHWEST HAVRE. THIS STORM WAS MOVING EAST AT
35 MPH. IT WILL CONTINUE TO MOVE THROUGH EASTERN CHOUTEAU COUNTY OVER
THE NEXT 45 MINUTES. EXPECT LARGE HAIL...STRONG WIND AND DANGEROUS
LIGHTNING TO ACCOMPANY THIS STORM.

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 6, 1:46 PM MDTSevere Thunderstorm WarningTFXFergus59 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.