Alert archive / Montana / Severe Thunderstorm Warnings in 1997

Severe Thunderstorm Warning 9, NWS Missoula, MT

May 31, 1997Lake County, Missoula County, Montana

NWS Missoula, MT issued this severe thunderstorm warning at May 31, 1997, 5:55 PM MDT for Lake County, Missoula County, Montana. It was in force for 65 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
May 31, 1997, 5:55 PM MDT (23:55 UTC)
Expired
May 31, 1997, 7:00 PM MDT
In force
65 min
Issued by
NWS Missoula, MT
Area
Whole counties

Counties Lake County, MT, Missoula County, MT

The radar

The Missoula radar (KMSX), 33 km from the middle of the area, began a volume at 23:54 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
May 31, 6:30 PM MDTThunderstorm Wind 63Huson, 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
May 31, 4:15 PM MDTSevere Thunderstorm WatchSPC6 hr

The nearest sounding before it

Spokane, WA (KOTX), launched 12:00Z, 11.9 hours before the alert went out and 184 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 12:00Z on 1997-05-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 11 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Spokane, WA at 12:00Z on 1997-05-31The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 14 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
11 J/kg
Mixed-layer CIN
-225 J/kg
Mixed-layer LCL
1213 m above ground
0-6 km bulk shear
50 kt
0-1 km storm-relative helicity
14 m²/s²
0-3 km storm-relative helicity
146 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 010000 RRA
SVRMSO
MTC047-063-010100-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MISSOULA MT
555 PM MDT SAT MAY 31 1997
 
THE NATIONAL WEATHER SERVICE IN MISSOULA HAS ISSUED A
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL  700 PM MDT
FOR PEOPLE IN THE FOLLOWING LOCATIONS...
 
IN WEST CENTRAL MONTANA
 
   ...SOUTHERN LAKE COUNTY...MISSOULA COUNTY
 
AT 555 PM MDT RADAR INDICATED A LINE OF SEVERE THUNDERSTORMS EXTENDING
FROM SOUTHERN LAKE COUNTY THROUGH WESTERN MISSOULA COUNTY. THE LINE IS
MOVING EAST AT 30 MPH...AND WILL PUSH THROUGH POLSON...ARLEE...AND
MISSOULA BY 615 PM MDT.
 
THESE STORMS MAY PRODUCE LARGE HAIL...HEAVY RAIN...AND WIND GUSTS TO 60
MPH.
 
WHEN THUNDERSTORMS ARE OCCURRING...PEOPLE SHOULD MOVE INSIDE A
STRONG BUILDING.  DO NOT STAND BY WINDOWS.  DON'T USE TELEPHONES
OR ELECTRICAL APPLIANCES UNLESS IN AN EMERGENCY UNTIL THE STORM
HAS PASSED.  MOTORISTS SHOULD NOT DRIVE INTO LOW WATE.R CROSSINGS.
 
WHITMORE/FOSS

The office that day

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

IssuedProductOfficeCountiesLasted
May 31, 4:25 PM MDTSevere Thunderstorm WarningMSOBeaverhead45 min
May 31, 4:30 PM MDTSevere Thunderstorm WarningMSOBeaverhead45 min
May 31, 4:34 PM MDTSevere Thunderstorm WarningMSOLincoln, Sanders41 min
May 31, 4:49 PM MDTSevere Thunderstorm WarningMSOMineral41 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.