Alert archive / Montana / Severe Thunderstorm Warnings in 1997

Severe Thunderstorm Warning 22, NWS Missoula, MT

July 19, 1997Powell County, Montana

NWS Missoula, MT issued this severe thunderstorm warning at Jul 19, 1997, 5:25 PM MDT for Powell County, Montana. It was in force for 50 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 19, 1997, 5:25 PM MDT (23:25 UTC)
Expired
Jul 19, 1997, 6:15 PM MDT
In force
50 min
Issued by
NWS Missoula, MT
Area
Whole counties

County Powell County, MT

The radar

The Missoula radar (KMSX), 82 km from the middle of the area, began a volume at 23:25 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 19, 5:40 PM MDTHail 0.75Avon, 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 12:00Z, 11.4 hours before the alert went out and 189 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 1997-07-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 122 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 1997-07-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 44 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
122 J/kg
Mixed-layer CIN
-92 J/kg
Mixed-layer LCL
1225 m above ground
0-6 km bulk shear
17 kt
0-1 km storm-relative helicity
44 m²/s²
0-3 km storm-relative helicity
51 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 192330
SVRMSO
MTC077-200015-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING...CORRECTED FOR STORM LOCATION
NATIONAL WEATHER SERVICE MISSOULA MT
525 PM MDT SAT JUL 19 1997

THE NATIONAL WEATHER SERVICE IN MISSOULA HAS ISSUED A
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL  615 PM MDT
FOR PEOPLE IN THE FOLLOWING LOCATION...

IN WEST CENTRAL MONTANA

   ...SOUTHERN AND CENTRAL POWELL COUNTY

AT 525 PM MDT MISSOULA RADAR INDICATED A SEVERE THUNDERSTORM 15 MILES
NORTHEAST OF DEER LODGE. THIS STORM IS MOVING TO THE NORTH AT 15 MPH JUST
EAST OF STATE HIGHWAY 141.

THIS STORM WILL LIKELY PRODUCE LARGE HAIL AND 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.

WHITMORE/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 19, 1:51 PM MDT, 3 hours 34 minutes earlier.

Area forecast discussion, Jul 19, 1:51 PM MDT, 3 hours 34 minutes before
WESTERN MONTANA AND NORTH CENTRAL IDAHO FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
145 PM MDT SAT JUL 19 1997

WE GOT OUR OWN LITTLE VERSION OF HURRICANE DANNY OVER THE NORTHERN
ROCKIES THIS AFTERNOON.  LARGE AREAS OF MODERATE TO HEAVY SHOWERS AND
HAIL-PRODUCING THUNDERSTORMS ROTATING AROUND LOW CENTER.  NEW MODELS
DID NOT VERIFY WELL ON POSITION OF LOW CENTER...THEY WERE ALL TOO FAR
SOUTH.  LOW APPEARS TO BE WAFFLING WESTWARD INTO NORTH CENTRAL IDAHO.
MODELS PROGRESS LOW VERY LITTLE THROUGH MIDDAY SUNDAY...THEN MOVE IT
TO THE EAST SUNDAY AFTERNOON.  HARD TO KNOW WHAT TO BELIEVE IN THIS
CUTOFF SITUATION.  WILL KEEP EARLY-PERIOD POPS UP...AND THEN SLOWLY
DRY THINGS SUNDAY NIGHT INTO MONDAY.  I KEPT IT FAIRLY CLOSE TO MOS
GUIDANCE.  NOT SURE WHETHER MOISTURE BANDS WILL MAKE IT DEEP INTO
NORTHWEST MONTANA...SO WILL SIT ON THE FENCE THERE.  SHOULD BE
ANOTHER ACTIVELY CONVECTIVE DAY AGAIN SUNDAY.             WHITMORE

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

LIB .. 057/079 057/084 ... 344442
FCA WE 056/077 056/082 053 345542
POL .. 057/077 057/084 ... 346542
MSO WE 056/076 056/085 053 347532
HMM .. 055/079 055/085 ... 347532
BTM .. 050/075 050/0r78 ... 347532
S80 .. 055/084 055/088 ... 344321
P69 .. 058/083 058/087 ... 345321
SMN .. 053/082 053/086 ... 346432

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 19, 8:30 AM MDTSevere Thunderstorm WarningMSOBeaverhead, Silver Bow60 min
Jul 19, 9:34 AM MDTSevere Thunderstorm WarningMSODeer Lodge56 min
Jul 19, 12:00 PM MDTSevere Thunderstorm WarningMSOPowell45 min
Jul 19, 2:19 PM MDTFlash Flood WarningMSOBeaverhead56 min
Jul 19, 2:19 PM MDTSevere Thunderstorm WarningMSOBeaverhead56 min
Jul 19, 3:06 PM MDTTornado WarningMSOBeaverhead69 min
Jul 19, 4:00 PM MDTSevere Thunderstorm WarningMSOSilver Bow60 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.