Alert archive / Montana / Severe Thunderstorm Warnings in 1997

Severe Thunderstorm Warning 69, NWS Missoula, MT

September 15, 1997Missoula County, Montana

NWS Missoula, MT issued this severe thunderstorm warning at Sep 15, 1997, 5:41 AM MDT for Missoula County, Montana. It was in force for 64 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
Sep 15, 1997, 5:41 AM MDT (11:41 UTC)
Expired
Sep 15, 1997, 6:45 AM MDT
In force
64 min
Issued by
NWS Missoula, MT
Area
Whole counties

County Missoula County, MT

The radar

The Missoula radar (KMSX), 5 km from the middle of the area, began a volume at 11:41 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
Sep 15, 6:30 AM MDTThunderstorm Wind 60Missoula, 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

Spokane, WA (KOTX), launched 00:00Z, 11.7 hours before the alert went out and 201 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 1997-09-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 1997-09-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -5 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1521 m above ground
0-6 km bulk shear
58 kt
0-1 km storm-relative helicity
-5 m²/s²
0-3 km storm-relative helicity
318 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 151143 RRA
SVRMSO
MTC063-151245-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MISSOULA MT
541 AM MDT MON SEP 15 1997
 
THE NATIONAL WEATHER SERVICE IN MISSOULA HAS ISSUED A
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL  645 AM MDT
FOR PEOPLE IN THE FOLLOWING LOCATION...
 
IN WEST CENTRAL MONTANA
 
   ...SOUTHEASTERN MISSOULA COUNTY
 
AT 530 AM...DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM WAS LOCATED 10
MILES SOUTHEAST OF LOLO. THE STORM WAS MOVING NORTHEAST AT 30 MPH AND
WILL MOVE THROUGH SOUTHEAST MISSOULA AND APPROACH MILTOWN BY 600 AM.
HAIL BETWEEN DIME TO NICKEL SIZE IS LIKELY WITH THE STORM ALONG WITH
HEAVY RAIN.
 
IF YOU ARE CAUGHT OUTSIDE...SEEK SHELTER FROM THE WEATHER IN A
STRONG BUILDING.  DAMAGING WIND...LARGE HAIL...VERY HEAVY RAIN...
AND DEADLY LIGHTNING ARE ALL POSSIBLE IN SEVERE THUNDERSTORMS.
STAY INSIDE AWAY FROM WINDOWS UNTIL THE STORM HAS PASSED.

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 Sep 15, 2:03 AM MDT, 3 hours 38 minutes earlier.

Area forecast discussion, Sep 15, 2:03 AM MDT, 3 hours 38 minutes before
WESTERN MONTANA AND NORTH CENTRAL IDAHO FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
200 AM MDT MON SEP 15 1997

WINDS HAVE SHIFTED TO THE NORTHWEST WITH PRESSURE RISING AT MSO WITH
THE PASSAGE OF A FAIRLY DRY SHORTWAVE AT THE SURFACE. TWO OTHER
FRONTAL BOUNDARIES EVIDENT ON SATELLITE AND FORECAST BY MODELS OVER
WASHINGTON/OREGON/IDAHO BORDERS AND ALONG WASHINGTON AND OREGON
COAST. FRONTAL BOUNDARY WITH UPPER LEVEL JET ENTERING INTO IDAHO THIS
MORNING WILL MOVE INTO WESTERN MONTANA BY DAYBREAK AND NEAR THE
DIVIDE BY LATE AFTERNOON. PREFER SLOWER ETA MODEL WHICH HAS FEATURES
MORE MERIDIONAL. 90KT JET ON FRONT SIDE OF TROUGH OVER OREGON AND
NORTHERN CA WILL MAKE FRONT PROGRESSIVE...BUT 90KT JET NEAR 50N 140W
WILL KEEP MOVEMENT IN CHECK. DYNAMICS ALONG FRONTAL BOUNDARY WEAKENS
AS IT APPROACHES THE DIVIDE. THUS WILL GO LIKELY POPS FOR IDAHO AND
WESTERN MT ZONES BUT CHANCE POPS OVER SOUTHWEST MT. MODELS HANDLE
INSTABILITY DIFFERENTLY FOR TODAY WITH ETA THE MOST STABLE AND NGM
VERY UNSTABLE. WILL GO WITH COMPROMISE OF AVN MODEL AND HAVE ISOLATED
THUNDERSTORMS OVER WEST CENTRAL MONTANA AND SCATTERED OVER SOUTHWEST
MT WHERE GREATEST INSTABILITY LIES. UPPER LEVEL TROUGH MOVES OVER CWA
AND BECOMES MORE ZONAL BY TUESDAY WITH SCATTERED SHOWERS IN MORE
STABLE ATMOSPHERE. FELSCH

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

LIB .. 061/045 060/... ... 30744
FCA WE 062/044 058/040 060 30744
POL .. 063/050 0460/... ... 30643
MSO WE 065/046 060/042 063 30643
HMM .. 066/044 062/... ... 30643
BTM .. 065/044 056/... ... 30553
S80 .. 064/047 060/... ... 30743
P69 .. 066/052 063/... ... 30753
SMN .. 066/044 063/... ... 30652

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 14, 9:30 PM MDTSevere Thunderstorm WarningMSOFlathead45 min
Sep 15, 10:40 AM MDTSevere Thunderstorm WarningMSOMissoula, Powell60 min
Sep 15, 10:50 AM MDTSevere Thunderstorm WarningMSOGranite, Powell40 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.