Alert archive / Montana / Severe Thunderstorm Warnings in 1997

Severe Thunderstorm Warning 16, NWS Missoula, MT

July 17, 1997Granite County, Montana

NWS Missoula, MT issued this severe thunderstorm warning at Jul 17, 1997, 7:00 PM MDT for Granite County, Montana. It was in force for 60 min. 1 report came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued
Jul 17, 1997, 7:00 PM MDT (01:00 UTC)
Expired
Jul 17, 1997, 8:00 PM MDT
In force
60 min
Issued by
NWS Missoula, MT
Area
Whole counties

County Granite County, MT

The radar

The Missoula radar (KMSX), 82 km from the middle of the area, began a volume at 01:02 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.

What was reported inside it

TimeReportWhereRemark
Jul 17, 7:30 PM MDTHail 1Philipsburg, MT

NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in.

The nearest sounding before it

Great_falls, MT (KTFX), launched 00:00Z, 1.0 hours before the alert went out and 246 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 1997-07-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 17 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 1997-07-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 22 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
17 J/kg
Mixed-layer CIN
-104 J/kg
Mixed-layer LCL
1361 m above ground
0-6 km bulk shear
45 kt
0-1 km storm-relative helicity
22 m²/s²
0-3 km storm-relative helicity
44 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 180102 RRA
SVRMSO
MTC039-180200-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MISSOULA MT
700 PM MDT THU JUL 17 1997
 
THE NATIONAL WEATHER SERVICE IN MISSOULA HAS ISSUED A
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL  800 PM MDT
FOR PEOPLE IN THE FOLLOWING LOCATION...
 
IN WEST CENTRAL MONTANA
 
   ...SOUTHERN GRANITE COUNTY
 
AT 700 PM MDT...MISSOULA DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM
20 MILES EAST-SOUTHEAST OF HAMILTON ALONG THE GRANITE AND RAVALLI COUNTY
BORDER. THIS STORM IS MOVING TO THE EAST AT 30 MPH AND WILL CONTINUE TO
MOVE ACROSS THE SAPPHIRE MOUNTAINS AND DEER LODGE NATIONAL FOREST. THIS
STORM IS EXPECTED TO MOVE INTO THE GEORGETOWN LAKE AREA...SOUTH OF
PHILIPSBURG BY 745 PM MDT.
 
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.  HEAVY RAINS FLOOD ROADS QUICKLY SO DON'T DRIVE INTO AREAS
WHERE WATER COVERS THE ROAD.
 
BELTZ

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 Jul 17, 1:56 PM MDT, 5 hours 4 minutes earlier.

Area forecast discussion, Jul 17, 1:56 PM MDT, 5 hours 4 minutes before
WESTERN MONTANA AND NORTH CENTRAL IDAHO FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
145 PM MDT THU JUL 17 1997

WEST COAST TROF TO MOVE ACROSS REGION TOMORROW. MINOR DIFFERENCES
BETWEEN MODELS WITH TRACK VORT CENTERS. HOWEVER...DYNAMICS APPEAR
WEAK WITH LITTLE IN THE WAY OF OMEGA GENERATED. MAIN VORT CENTER AT
BOTTOM OF TROF GOES THRU NORTHERN CALIF/NV BEFORE SWING NORTH INTO SW
MT LATE FRIDAY AFTERNOON/EVENING. MODELS HAVE DRIER AIR MASS FOR
TOMORROW AS SUB-TROPICAL MOISTURE MOVES EDVD. PRIMARY AREA FOR ANY
ACTIVITY ON FRIDAY IS OVER SW MT WHERE MOISTURE CONVERGENCE...LOW
LI'S AND CAPES CONVERGE. HAVE GONE SLIGHTLY HIGHER THAN MOS POPS MOST
AREAS FRIDAY...MAINLY DUE TO TROF PASSAGE. FOR THIS EVENING STILL
PLENTY OF MOISTURE AROUND ALTHOUGH SATELLITE IMAGERY BEGINNING TO
SHOW BREAK IN CLOUDS. WILL KEEP SCATTERED POPS AND CHANCE OF A FEW
TSTMS THRU THE EVENING HOURS. FOSS

...FORECASTS BELOW ARE PRELIMINARY AND SUBJECT TO CHANGE...

LIB .. 052/076 050/082 ... 313211
FCA BB 050/075 048/080 047 313211
POL .. 055/079 053/084 ... 313211
MSO BB 055/079 052/082 050 313211
HMM .. 053/080 050/085 ... 313211
BTM .. 053/075 050/078 ... 313341
S80 .. 055/076 053/080 ...@ 313310
P69 .. 057/080 055/084 ... 313310
SMN .. 054/076 050/085 ... 313321

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 17, 6:12 PM MDTSevere Thunderstorm WarningMSORavalli48 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; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.