Alert archive / Montana / Severe Thunderstorm Warnings in 1998

Severe Thunderstorm Warning 50, NWS Missoula, MT

August 20, 1998Sanders County, Montana

NWS Missoula, MT issued this severe thunderstorm warning at Aug 20, 1998, 10:19 PM MDT for Sanders County, Montana. It was in force for 61 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
Aug 20, 1998, 10:19 PM MDT (04:19 UTC)
Expired
Aug 20, 1998, 11:20 PM MDT
In force
61 min
Issued by
NWS Missoula, MT
Area
Whole counties

County Sanders County, MT

The nearest sounding before it

Spokane, WA (KOTX), launched 00:00Z, 4.3 hours before the alert went out and 95 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 1998-08-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 18 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 1998-08-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 15 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
18 J/kg
Mixed-layer CIN
-169 J/kg
Mixed-layer LCL
3285 m above ground
0-6 km bulk shear
41 kt
0-1 km storm-relative helicity
15 m²/s²
0-3 km storm-relative helicity
66 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 210419 RRA
SVRMSO
MTC089-210520-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MISSOULA MT
1019 PM MDT THU AUG 20 1998

THE NATIONAL WEATHER SERVICE HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTH CENTRAL SANDERS COUNTY IN WEST CENTRAL MONTANA

* UNTIL 1120 PM MDT

* AT AT 1010 PM MDT...SEVERE THUNDERSTORM INDICATED 5 WEST OF
  THOMPSON FALLS...BY NATIONAL WEATHER SERVICE DOPPLER RADAR...
  MOVING NORTH AT 15 MPH.

* SEVERE THUNDERSTORM WILL BE NEAR...
  BELKNAP AT 1025 PM MDT
  TROUT CREEK AT 1040 PM 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, 8:30 PM MDT, 1 hour 49 minutes earlier.

Area forecast discussion, Aug 20, 8:30 PM MDT, 1 hour 49 minutes before
WESTERN MONTANA AND NORTH CENTRAL IDAHO FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
830 PM MDT THU AUG 20 1998

BUSY WITH A COUPLE OF FIRE WEATHER SPOTS AND SEVERE WEATHER
STATEMENTS THIS EVENING. HAD A REPORT OF 1 INCH HAIL AT SUPERIOR
MONTANA EARLIER THIS EVENING. SATELLITE WATER VAPOR AND IR INDICATING
THE STRONGEST TSTM ACTIVITY OVER NORTHWEST AND SOUTHWEST MONTANA
ATTM. WILL UPDATE MONTANA ZONES TO BUMP POPS UP NORTHWEST MONTANA AND
KEEP MENTION OF TSTMS OVERNIGHT IN THE SOUTHWEST. FRIDAY MAX
TEMPERATURES LOOK TOO COOL AS READINGS TODAY MUCH WARMER THAN
EXPECTED SO NEED TO UPDATE IDAHO ZONES AS WELL. HARMER

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

LIB .. 052/086 048/080 ... 322221
FCA BB 049/085 045/078 044 322221
POL .. 054/083 052/076 ... 322231
MSO BB 052/086 050/080 049 322131
HMM .. 055/088 054/080 ... 322130
BTM .. 052/084 050/075 ... 322130
S80 .. 053/086 050/080 ... 321231
P69 .. 056/092 053/087 ... 322231
SMN .. 050/086 049/083 ... 322231

In the hours before

Local storm report, Aug 20, 8:15 PM MDT, 2 hours 4 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MISSOULA MT
815 PM MDT THU AUG 20 1998

TIME(MDT)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION......

0607 PM    SUPERIOR                  MT    1.00 INCH HAIL
08/20/98   MINERAL                         WEATHER SPOTTER
Local storm report, Aug 20, 8:15 PM MDT, 2 hours 4 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MISSOULA MT
815 PM MDT THU AUG 20 1998

TIME(MDT)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION......

0607 PM    SUPERIOR                  MT    1.00 INCH HAIL
08/20/98   MINERAL                         WEATHER SPOTTER

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 20, 6:25 PM MDTSevere Thunderstorm WarningMSOSanders60 min

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; the sounding from the Mesonet's radiosonde archive.