Alert archive / Montana / Severe Thunderstorm Warnings in 1991
Severe Thunderstorm Warning 21, NWS Great Falls, MT
NWS Great Falls, MT issued this severe thunderstorm warning at Aug 14, 1991, 3:08 PM MDT for Fergus County, Montana. It was in force for 52 min.
The area
The counties it named.
The facts
- Issued
- Aug 14, 1991, 3:08 PM MDT (21:08 UTC)
- Expired
- Aug 14, 1991, 4:00 PM MDT
- In force
- 52 min
- Issued by
- NWS Great Falls, MT
- Area
- Whole counties
County Fergus County, MT
The nearest sounding before it
Great Falls, MT (KGTF), launched 12:00Z, 9.1 hours before the alert went out and 158 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.
- Mixed-layer CAPE
- 244 J/kg
- Mixed-layer CIN
- -86 J/kg
- Mixed-layer LCL
- 832 m above ground
- 0-6 km bulk shear
- 34 kt
- 0-1 km storm-relative helicity
- -27 m²/s²
- 0-3 km storm-relative helicity
- 18 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.1
The text
As transmitted, in the capitals the NWS used until 2016.
000 TTAA00 KGTF 142108 SVRGTF MTC027-045-142200- BULLETIN - IMMEDIATE BROADCAST REQUESTED SEVERE THUNDERSTORM WARNING NATIONAL WEATHER SERVICE GREAT FALLS MT 308 PM MDT WED AUG 14 1991 THE NATIONAL WEATHER SERVICE IN GREAT FALLS HAS ISSUED A SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL 400 PM MDT FOR PEOPLE IN THE FOLLOWING LOCATION...S... IN NORTH CENTRAL MONTANA ...NORTHWESTERN FERGUS COUNTY...NORTHERN JUDITH BASIN COUNTY AT 3 PM WEATHER RADAR SHOWED A SEVERE THUNDERSTORM IN NORTHERN JUDITH BASIN COUNTY JUST WEST AND NORTH OF THE TOWN OF STANFORD. THIS THUNDERSTORM WAS MOVING SLOWLY EAST AT AROUND 10 MILES AN HOUR. IF YOU ARE CAUGHT OUTSIDE...SEEK SHELTER FROM THE WEATHER IN A STRONG BUILDING. DAMA/GING WIND...LARGE HAIL...VERY HEAVY RAIN... AND DEADLY LIGHTNING ARE ALL POSSIBLE IN SEVERE THUNDERSTORMS. STAY INSIDE AWAY FROM WINDOWS UNTIL THE STORM HAS PASSED. GRAHAM
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.
In the hours before
Local storm report, Aug 14, 10:08 AM MDT, 5 hours before
STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS, MT
1007 AM MDT WED AUG 14 1991
...ALL DATA FOR TUESDAY AUGUST 13...
TIME EVENT
528 PM MDT REPORTS OF HAIL UP TO THE SIZE OF SOFTBALLS IN THE
BRADY AREA OF EASTERN PONDERA COUNTY RECEIVED BY
CO-OP OBSERVER AT THE KNEES. OTHER REPORTS OF SOFT
BALL SIZE HAIL RECEIVED BY RADIO STATION KSEN AT
APPROXIMATELY THE SAME TIME.
554 PM MDT GOLF BALL SIZE HAIL FELL AT THE KNEES IN NORTHWEST
CHOTEAU COUNTY. HAIL BROKE A CAR`S WINDSHIELD.
730 PM MDT .40 INCH OF RAIN FALLS AT FORT BENTON IN CHOTEAU
COUNTY BETWEEN 710 AND 730 PM.
1035 PM MDT MARBLE SIZE HAIL FALLS 10 MILES EAST OF BRADYThe office that day
Everything else NWS Great Falls, MT issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 13, 6:01 PM MDT | Severe Thunderstorm Warning | TFX | Chouteau | 44 min |
| Aug 13, 6:50 PM MDT | Severe Thunderstorm Warning | TFX | Chouteau | 2 hr |
| Aug 14, 3:08 PM MDT | Severe Thunderstorm Warning | TFX | Judith Basin | 33 min |
| Aug 14, 4:01 PM MDT | Severe Thunderstorm Warning | TFX | Fergus | 44 min |
Nearby
Severe Thunderstorm Warnings in Montana, 1991Every severe thunderstorm warning in 1991
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.