Alert archive / Montana / Severe Thunderstorm Warnings in 1997

Severe Thunderstorm Warning 51, NWS Missoula, MT

August 7, 1997Granite County, Powell County, Montana

NWS Missoula, MT issued this severe thunderstorm warning at Aug 7, 1997, 7:15 PM MDT for Granite County, Powell 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
Aug 7, 1997, 7:15 PM MDT (01:15 UTC)
Expired
Aug 7, 1997, 8:00 PM MDT
In force
45 min
Issued by
NWS Missoula, MT
Area
Whole counties

Counties Granite County, MT, Powell County, MT

The radar

The Missoula radar (KMSX), 76 km from the middle of the area, began a volume at 01:15 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, 1.3 hours before the alert went out and 217 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 1997-08-08Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 655 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 1997-08-08The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -8 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
655 J/kg
Mixed-layer CIN
-41 J/kg
Mixed-layer LCL
2423 m above ground
0-6 km bulk shear
7 kt
0-1 km storm-relative helicity
-8 m²/s²
0-3 km storm-relative helicity
72 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 KMSO 080118 RRA
SVRMSO
MTC039-077-080200-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MISSOULA MT
715 PM MDT THU AUG 7 1997
 
THE NATIONAL WEATHER SERVICE IN MISSOULA HAS ISSUED A
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL  8 PM MDT
FOR PEOPLE IN THE FOLLOWING LOCATIONS...
 
IN WEST CENTRAL MONTANA
 
   ...EASTERN GRANITE COUNTY...POWELL COUNTY
 
AT 715 PM MDT...MISSOULA DOPPLER RADAR INDICATED SEVERE THUNDERSTORMS IN
EASTERN GRANITE AND POWELL COUNTIES. THE STORMS IN POWELL COUNTY WERE
NEAR HELMVILLE WITH ANOTHER 3 MILES NORTH OF DRUMMOND AND THE FINAL
STORM 10 MILES SOUTH OF GARRISON. IN GRANITE COUNTY...A SEVERE STORM WAS
NEAR MAXVILLE. THIS STORM PRODUCED ONE INCH IN DIAMETER HAIL AT 705 PM
MDT IN MAXVILLE.
 
SEVERE THUNDERSTORMS PRODUCE DAMAGING WIND IN EXCESS OF 55 MPH
...DESTRUCTIVE HAIL...DEADLY LIGHTNING...AND VERY HEAVY RAIN.
FOR YOUR PROTECTION MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR*
OF YOUR HOME OR BUSINESS.
 
BELTZ/CLEMMONS
&

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.

NWS Missoula, MT wrote its last area forecast discussion before this severe thunderstorm warning went out at Aug 7, 1:45 PM MDT, 5 hours 30 minutes earlier.

Area forecast discussion, Aug 7, 1:45 PM MDT, 5 hours 30 minutes before
WESTERN MONTANA AND NORTH CENTRAL IDAHO FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
145 PM MDT THU AUG 7 1997

SFC FRONT STILL EXTENDS FROM EXTREME NORTHWEST MT TO SOUTHEAST WA.
ISOLATED TSTMS IN PANHANDLE AND NORTHWEST MONTANA WITH FIRST WARNING
JUST ISSUED FOR STORM NEAR FCA. BUILDUPS STILL OCCURRING AHEAD OF
FRONT OVER CENTRAL ID/SOUTHWEST MT SO NOT OUT OF WOODS YET IN THESE
AREAS SINCE FRONT/ASSOCIATED SHORTWAVE STILL YET TO PUSH EAST...WHICH
SHOULD TRIGGER SCATTERED TSTMS IN THESE AREAS BY LATE AFTERNOON DUE
TO VERY UNSTABLE ATMOSPHERE. BECOMING COOL AND DRY BEHIND FRONT BUT
CHANNELED VORT WITH SOME MOISTURE WORKING THROUGH WEST MONTANA LATER
FRIDAY INTO SATURDAY. DYNAMICS LACKING SO MAY ONLY MENTION ISOLATED
SHOWERS OVER THE NORTHERN MOUNTAINS. BELTZ

...FORECASTS BELOW ARE PRELIMINARY AND SUBJECT TO CHANGE...
LIB .. 047/074 045/073 ... 2710-1
FCA BB 049/075 046/073 046 2710-1
POL .. 053/077 051/075 ... 271001
MSO BB 052/080 048/078 048 27200-
HMM .. 049/082 046/080 ... 272000
BTM .. 048/080 045/077 ... 273000
S80 .. 056/081 051/080 ... 271000
P69 .. 058/083 053/082 ... 272000
SMN .. 050/083 047/082 ... 272000

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 7, 6:15 PM MDTSevere Thunderstorm WarningMSOGranite, Missoula, Powell60 min
Aug 7, 8:00 PM MDTSevere Thunderstorm WarningMSOPowell45 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.