Alert archive / Montana / Severe Thunderstorm Warnings in 1997

Severe Thunderstorm Warning 15, NWS Missoula, MT

July 17, 1997Ravalli County, Montana

NWS Missoula, MT issued this severe thunderstorm warning at Jul 17, 1997, 6:12 PM MDT for Ravalli 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
Jul 17, 1997, 6:12 PM MDT (00:12 UTC)
Expired
Jul 17, 1997, 7:00 PM MDT
In force
48 min
Issued by
NWS Missoula, MT
Area
Whole counties

County Ravalli County, MT

The radar

The Missoula radar (KMSX), 107 km from the middle of the area, began a volume at 00:13 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

Spokane, WA (KOTX), launched 00:00Z, 0.2 hours before the alert went out and 250 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, Spokane, WA at 00:00Z on 1997-07-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 107 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, Spokane, WA at 00:00Z on 1997-07-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 20 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
107 J/kg
Mixed-layer CIN
-33 J/kg
Mixed-layer LCL
2404 m above ground
0-6 km bulk shear
57 kt
0-1 km storm-relative helicity
20 m²/s²
0-3 km storm-relative helicity
77 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000 
TTAA00 KMSO 180014 RRA
SVRMSO
MTC081-180100-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MISSOULA MT
612 PM MDT THU JUL 17 1997
 
THE NATIONAL WEATHER SERVICE IN MISSOULA HAS ISSUED A
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL 700 PM MDT
FOR PEOPLE IN THE FOLLOWING LOCATION...
 
IN WEST CENTRAL MONTANA
 
   ...CENTRAL RAVALLI COUNTY
 
AT 610 PM MDT...MISSOULA DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM 5
MILES NORTHWEST OF DARBY. THIS STORM WAS MOVING TO THE NORTHEAST AT 20
MPH AND IS EXPECTED TO MOVE ACROSS HIGHWAY 93 BETWEEN HAMILTON AND DARBY
BY 630 PM MDT AND THEN INTO THE SAPPHIRE MOUNTAINS. THIS STORM HAS
ALREADY PRODUCE 1/2 INCH IN DIAMETER HAIL NEAR DARBY.
 
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 QUIvCKLY 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, 4 hours 16 minutes earlier.

Area forecast discussion, Jul 17, 1:56 PM MDT, 4 hours 16 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, 7:00 PM MDTSevere Thunderstorm WarningMSOGranite60 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.