Alert archive / Montana / Severe Thunderstorm Warnings in 1997

Severe Thunderstorm Warning 47, NWS Great Falls, MT

July 19, 1997Cascade County, Montana

NWS Great Falls, MT issued this severe thunderstorm warning at Jul 19, 1997, 6:30 PM MDT for Cascade County, Montana. It was in force for 30 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 19, 1997, 6:30 PM MDT (00:30 UTC)
Expired
Jul 19, 1997, 7:00 PM MDT
In force
30 min
Issued by
NWS Great Falls, MT
Area
Whole counties

County Cascade County, MT

The radar

The Great Falls radar (KTFX), 17 km from the middle of the area, began a volume at 00:32 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 00:00Z, 0.5 hours before the alert went out and 59 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 1997-07-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 202 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 00:00Z on 1997-07-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -26 square meters per square second.19395878Sfc1 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
202 J/kg
Mixed-layer CIN
-77 J/kg
Mixed-layer LCL
1458 m above ground
0-6 km bulk shear
23 kt
0-1 km storm-relative helicity
-26 m²/s²
0-3 km storm-relative helicity
24 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 200032 RRA
SVRGTF
MTC013-200100-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE GREAT FALLS MT
630 PM MDT SAT JUL 19 1997
 
THE NATIONAL WEATHER SERVICE IN GREAT FALLS HAS ISSUED A
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL  700 PM MDT
FOR PEOPLE IN THE FOLLOWING LOCATION...
 
IN NORTH MONTANA
 
   ...SOUTHERN CASCADE COUNTY
 
RADAR INDICATES A SEVERE THUNDERSTORM OVER SOUTHERN CASCADE COUNTY
MOVING NORTH AT 15 TO 20 MPH. THIS THUNDERSTORM SHOULD REACH THE TOWN OF
CASCADE BY 645 PM MDT. HEAVY RAIN AND LARGE HAIL CAN BE EXPECTED WITH
THIS THUNDERSTORM.

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.