Alert archive / Montana / Severe Thunderstorm Warnings in 1997

Severe Thunderstorm Warning 77, NWS Great Falls, MT

September 15, 1997Lewis and Clark County, Montana

NWS Great Falls, MT issued this severe thunderstorm warning at Sep 15, 1997, 12:27 PM MDT for Lewis and Clark County, Montana. It was in force for 48 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
Sep 15, 1997, 12:27 PM MDT (18:27 UTC)
Expired
Sep 15, 1997, 1:15 PM MDT
In force
48 min
Issued by
NWS Great Falls, MT
Area
Whole counties

County Lewis and Clark County, MT

The nearest sounding before it

Great_falls, MT (KTFX), launched 12:00Z, 6.5 hours before the alert went out and 140 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 1997-09-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 54 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 1997-09-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 156 square meters per square second.1939587897Sfc1 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
54 J/kg
Mixed-layer CIN
-492 J/kg
Mixed-layer LCL
1231 m above ground
0-6 km bulk shear
37 kt
0-1 km storm-relative helicity
156 m²/s²
0-3 km storm-relative helicity
181 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 151829 RRA
SVRGTF
MTC049-151915-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE GREAT FALLS MT
1227 PM MDT MON SEP 15 1997
 
THE NATIONAL WEATHER SERVICE IN GREAT FALLS HAS ISSUED A
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL  115 PM MDT
FOR PEOPLE IN THE FOLLOWING LOCATION...
 
IN SOUTHWEST MONTANA
 
   ...SOUTHERN LEWIS AND CLARK COUNTY
 
AT 1225 PM...AN OBSERVER IN BOULDER REPORTED A SEVERE THUNDERSTORM WITH
A WIND GUST TO NEAR 60 MPH. THIS STORM WAS MOVING NORTHEAST AT 35 MPH
AND WILL MOVE OVER THE TOWN OF HELENA BY 1240 PM AND OVER NORTHERN
CANYON FERRY AREA BY 1250. STRONG GUSTY WINDS TO NEAR 60 MPH...HEAVY
RAIN AND HAIL ARE LIKELY WITH THIS STORM.
&

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 15, 11:46 AM MDTSevere Thunderstorm WarningTFXLewis and Clark44 min
Sep 15, 12:36 PM MDTSevere Thunderstorm WarningTFXCascade, Lewis and Clark54 min
Sep 15, 1:04 PM MDTSevere Thunderstorm WarningTFXCascade41 min
Sep 15, 1:42 PM MDTSevere Thunderstorm WarningTFXCascade, Chouteau, Judith Basin63 min
Sep 15, 2:42 PM MDTSevere Thunderstorm WarningTFXBlaine, Chouteau, Hill63 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.