Alert archive / Montana / Severe Thunderstorm Warnings in 1998
Severe Thunderstorm Warning 47, NWS Missoula, MT
NWS Missoula, MT issued this severe thunderstorm warning at Aug 7, 1998, 4:31 PM MDT for Powell County, Montana. It was in force for 34 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 7, 1998, 4:31 PM MDT (22:31 UTC)
- Expired
- Aug 7, 1998, 5:05 PM MDT
- In force
- 34 min
- Issued by
- NWS Missoula, MT
- Area
- Whole counties
County Powell County, MT
The nearest sounding before it
Great_falls, MT (KTFX), launched 12:00Z, 10.5 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.
- Mixed-layer CAPE
- 70 J/kg
- Mixed-layer CIN
- -254 J/kg
- Mixed-layer LCL
- 1445 m above ground
- 0-6 km bulk shear
- 34 kt
- 0-1 km storm-relative helicity
- 90 m²/s²
- 0-3 km storm-relative helicity
- 153 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
570 WUUS1 KMSO 072235 RRA SVRMSO MTC077-072305- BULLETIN - IMMEDIATE BROADCAST REQUESTED SEVERE THUNDERSTORM WARNING NATIONAL WEATHER SERVICE MISSOULA MT 431 PM MDT FRI AUG 7 1998 THE NATIONAL WEATHER SERVICE HAS EXTENDED A * SEVERE THUNDERSTORM WARNING FOR... SOUTHERN POWELL COUNTY IN WEST CENTRAL MONTANA * UNTIL 505 PM MDT * AT 430 PM MDT...SEVERE THUNDERSTORM INDICATED 5 MILES SOUTHEAST OF HELMVILLE...BY NATIONAL WEATHER SERVICE DOPPLER RADAR... MOVING NORTHEAST AT 25 MPH. * SEVERE THUNDERSTORM WILL BE NEAR... STATE ROUTE 141...5 MILES EAST OF HELMVILLE AT 445 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 7, 2:30 PM MDT, 2 hours 1 minute earlier.
Area forecast discussion, Aug 7, 2:30 PM MDT, 2 hours 1 minute before
WESTERN MONTANA AND NORTH CENTRAL IDAHO FORECAST DISCUSSION NATIONAL WEATHER SERVICE MISSOULA MT 230 PM MDT FRI AUG 7 1998 VORT CENTER CRUISING OVER CENTRAL WASHINGTON IDENTIFIED WELL BY ETA ALONG WITH SURFACE CONVERGENCE ZONE OVER SOUTHWEST MONTANA WHERE ACTIVITY STILL GENERATING WHILE SLIPPING SOUTHEASTWARD. CONVECTIVE INSTABILITIES STILL REMAIN FAVORABLE OVER THE ENTIRE CWA FOR THIS AFTERNOON AND EVENING ISOLATED ACTIVITY...MORE SCATTERED SOUTH. BY SATURDAY MORNING...HEIGHTS START TO RISE REDEFINING AND BUILDING UPPER RIDGE OVER THE FORECAST AREA. ETA SUGGEST BEST INSTABILITY TO SHIFT EAST OF THE DIVIDE WITH DRIER AIR ADVECTING OVER CWA. TEMPERATURES TREND UPWARD FOR SUNDAY AS THERMAL TROF REDEVELOPS OVER WESTERN IDAHO. STOLL LIB .. 047/087 048/088 ... 332000 FCA UU 048/088 049/089 051 332000 POL .. 049/086 050/087 ... 332000 MSO UU 053/088 051/091 053 332000 HMM .. 055/090 054/093 ... 332000 BTM .. 048/088 047/091 ... 332100 S80 .. 053/089 054/090 ... 331000 P69 .. 055/091 054/091 ... 331000 SMN .. 049/089 048/090 ... 331000
The office that day
Everything else NWS Missoula, MT issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 7, 12:15 AM MDT | Severe Thunderstorm Warning | MSO | Missoula, Ravalli | 60 min |
| Aug 7, 2:33 PM MDT | Severe Thunderstorm Warning | MSO | Deer Lodge | 47 min |
| Aug 7, 3:43 PM MDT | Severe Thunderstorm Warning | MSO | Powell | 47 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.