Alert archive / Montana / Severe Thunderstorm Warnings in 1997

Severe Thunderstorm Warning 81, NWS Great Falls, MT

September 15, 1997Blaine County, Chouteau County, Hill County, Montana

NWS Great Falls, MT issued this severe thunderstorm warning at Sep 15, 1997, 2:42 PM MDT for Blaine County, Chouteau County, Hill County, Montana. It was in force for 63 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, 2:42 PM MDT (20:42 UTC)
Expired
Sep 15, 1997, 3:45 PM MDT
In force
63 min
Issued by
NWS Great Falls, MT
Area
Whole counties

Counties Blaine County, MT, Chouteau County, MT, Hill County, MT

The radar

The Great Falls radar (KTFX), 150 km from the middle of the area, began a volume at 20:44 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, 8.7 hours before the alert went out and 111 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 152044
SVRGTF
MTC005-015-041-152145-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE GREAT FALLS MT
242 PM MDT MON SEP 15 1997
 
THE NATIONAL WEATHER SERVICE IN GREAT FALLS HAS ISSUED A
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL  345 PM MDT
FOR PEOPLE IN THE FOLLOWING LOCATIONS...
 
IN NORTH CENTRAL MONTANA
 
   ...WESTERN BLAINE COUNTY...EASTERN CHOUTEAU COUNTY
   ...CENTRAL AND EASTERN HILL COUNTY
 
DOPPLER RADAR INDICATES A SQUALL LINE MOVING TO THE NORTHEAST AT 40 MPH.
WIND SPEEDS IN EXCESS OF 60 MPH HAVE BEEN REPORTED WITH THESE STORMS
ALONG WITH HAIL AND BRIEF HEAVY RAIN. THE SQUALL LINE SHOULD REACH THE
HAVRE AREA BETWEEN 3 AND 315 PM THIS AFTERNlOON.
 
 
 
&

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

Special weather statement, Sep 15, 1:26 PM MDT, 1 hour 16 minutes before
MTZ014-151930-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREAT FALLS MT
120 PM MDT MON SEP 15 1997

...SEVERE THUNDERSTORM WARNING FOR SOUTHERN LEWIS AND CLARK COUNTY HAS
   BEEN ALLOWED TO EXPIRE...

...SEVERE THUNDERSTORM WARNING CONTINUES FOR NORTHERN CASCADE COUNTY
   UNTIL 145 PM MDT...

THE SEVERE THUNDERSTORM THAT DEVELOPED OVER SOUTHERN LEWIS AND CLARK HAS
DIMINISHED IN INTENSITY AND HAS MOVED EAST INTO NORTHERN BROADWATER
COUNTY. REPORTS OF WIND GUSTS TO 60 MPH AND HAIL THREE-QUARTER INCH IN
DIAMETER WERE REPORTED IN THE HELENA AREA.

A SEVERE THUNDERSTORM OVER NORTHERN CASCADE COUNTY CONTINUES TO MOVE
NORTHEAST AT 40 MPH. STRONG GUSTY WINDS IN EXCESS OF 55 MPH...HEAVY
RAIN AND HAIL HAVE BEEN REPORTED WITH THIS STORM.
&

&
Special weather statement, Sep 15, 1:27 PM MDT, 1 hour 15 minutes before
MTZ014-151930-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREAT FALLS MT
120 PM MDT MON SEP 15 1997

...SEVERE THUNDERSTORM WARNING FOR SOUTHERN LEWIS AND CLARK COUNTY HAS
   BEEN ALLOWED TO EXPIRE...

...SEVERE THUNDERSTORM WARNING CONTINUES FOR NORTHERN CASCADE COUNTY
   UNTIL 145 PM MDT...

THE SEVERE THUNDERSTORM THAT DEVELOPED OVER SOUTHERN LEWIS AND CLARK HAS
DIMINISHED IN INTENSITY AND HAS MOVED EAST INTO NORTHERN BROADWATER
COUNTY. REPORTS OF WIND GUSTS TO 60 MPH AND HAIL THREE-QUARTER INCH IN
DIAMETER WERE REPORTED IN THE HELENA AREA.

A SEVERE THUNDERSTORM OVER NORTHERN CASCADE COUNTY CONTINUES TO MOVE
NORTHEAST AT 40 MPH. STRONG GUSTY WINDS IN EXCESS OF 55 MPH...HEAVY
RAIN AND HAIL HAVE BEEN REPORTED WITH THIS STORM.
&

&
Special weather statement, Sep 15, 2:07 PM MDT, 35 minutes before
MTZ012-013-152015-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREAT FALLS MT
203 PM MDT MON SEP 15 1997

...SEVERE THUNDERSTORM WARNING FOR NORTHERN CASCADE COUNTY HAS
   EXPIRED...

...SEVERE THUNDERSTORM WARNING CONTINUES UNTIL 230 PM MDT FOR EAST CENTR
   CASCADE COUNTY...SOUTHWESTERN CHOUTEAU COUNTY AND NORTHWESTERN JUDITH
A   COUNTY...

THUNDERSTORMS ACROSS NORTHERN CASCADE COUNTY HAVE DIMINISHED IN INTENSIT
ATHEY MOVE INTO CHOUTEAU COUNTY.

AT 2PM MDT...AN AREA OF SEVERE THUNDERSTORMS CONTINUED TO MOVE TOWARD NO
HAT 45 MPH ACROSS EAST CENTRAL CASCADE COUNTY. STRONG GUSTY WINDS IN EXCE
OF 55 MPH ALONG WITH HAIL THREE-QUARTER INCH IN DIAMETER HAVE BEEN REPOR
DWITH THESER STORMS.

&

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, 12:27 PM MDTSevere Thunderstorm WarningTFXLewis and Clark48 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

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.