Alert archive / Montana / Severe Thunderstorm Warnings in 1998

Severe Thunderstorm Warning 48, NWS Missoula, MT

August 20, 1998Mineral County, Montana

NWS Missoula, MT issued this severe thunderstorm warning at Aug 20, 1998, 5:32 PM MDT for Mineral County, Montana. It was in force for 63 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
Aug 20, 1998, 5:32 PM MDT (23:32 UTC)
Expired
Aug 20, 1998, 6:35 PM MDT
In force
63 min
Issued by
NWS Missoula, MT
Area
Whole counties

County Mineral County, MT

What was reported inside it

TimeReportWhereRemark
Aug 20, 6:07 PM MDTHail 1Superior, 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 12:00Z, 11.5 hours before the alert went out and 122 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 1998-08-20Temperature 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 12:00Z on 1998-08-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 17 square meters per square second.193958Sfc1 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
2346 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
17 m²/s²
0-3 km storm-relative helicity
27 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.

747 
WUUS1 KMSO 202333 RRA
SVRMSO
MTC061-210035-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MISSOULA MT
532 PM MDT THU AUG 20 1998

THE NATIONAL WEATHER SERVICE HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHERN MINERAL COUNTY IN WEST CENTRAL MONTANA

* UNTIL 635 PM MDT

* AT 530PM MDT...SEVERE THUNDERSTORM INDICATED 10 MILES SOUTHWEST
  OF ALBERTON...BY NATIONAL WEATHER SERVICE DOPPLER RADAR...MOVING
  NORTH 15 MPH.

* SEVERE THUNDERSTORM WILL...
  CROSS HIGHWAY I-90 10 MILES WEST OF ALBERTON BY
  545PM 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 DO NOT DRIVE
INTO AREAS WHERE WATER COVERS THE ROAD.

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 Aug 20, 2:45 PM MDT, 2 hours 47 minutes earlier.

Area forecast discussion, Aug 20, 2:45 PM MDT, 2 hours 47 minutes before
WESTERN MONTANA AND NORTH CENTRAL IDAHO FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
245 PM MDT THU AUG 20 1998

FIRE WEATHER FORECASTER WILL CONTINUE THE RED FLAG WARNING THRU THIS
EVENING FOR FIRE WEATHER ZONES SOUTHERN 103B..SOUTHERN 106 AND 107B.

DRY UNSTABLE ATMOSPHERE TONIGHT WITH A WEAK SHORTWAVE ROTATING NORTH
THRU CENTRAL IDAHO UP INTO NORTHWEST MONTANA BY MORNING. BEST
MOISTURE IF YOU CAN CALL IT THAT RESIDING OVER THE SOUTHERN HALF OF
THE MISSOULA COUNTY WARNING AREA WITH INVERTED V SOUNDINGS INDICATED.
UPPER LOW OVER NORTHERN CALIFORNIA BEGINS TO OPEN UP NEXT 12 TO 24
HOURS AND BEGINS TO ROTATE A TROUGH NORTHEAST OVER THE AREA BETWEEN
00Z SATURDAY AND 12Z SATURDAY MORNING. SOUNDINGS INDICATE DEEPENING
MOISTURE SO WILL GO WITH CHANCE POPS BY FRIDAY EVENING...MAINLY
SOUTHERN HALF. WEAK SHORTWAVE AND MOISTURE MOVES ACROSS NORTHERN
PORTION OF MISSOULA COUNTY WARNING AREA SATURDAY...HOWEVER AREA WILL
BE STABILIZING FOR ONLY ISOLATED ACTIVITY.
TC
...FORECASTS BELOW ARE PRELIMINARY AND SUBJECT TO CHANGE...

LIB .. 052/081 048/080 ... 291221
FCA BB 049/080 045/078 044 291221
POL .. 054/083 052/076 ... 291221
MSO BB 052/084 050/080 049 292121
HMM .. 055/085 054/080 ... 292120
BTM .. 052/080 050/075 ... 292120
S80 .. 053/082 050/080 ... 291231
P69 .. 056/090 053/087 ... 292231
SMN .. 050/086 049/083 ... 292231

Nearby

Severe Thunderstorm Warnings in Montana, 1998Every severe thunderstorm warning in 1998

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.