Alert archive / Montana / Severe Thunderstorm Warnings in 1991
Severe Thunderstorm Warning 21, NWS Billings, MT
NWS Billings, MT issued this severe thunderstorm warning at Jun 21, 1991, 4:36 PM MDT for Treasure County, Yellowstone County, Montana. It was in force for 69 min. 2 reports 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
- Jun 21, 1991, 4:36 PM MDT (22:36 UTC)
- Expired
- Jun 21, 1991, 5:45 PM MDT
- In force
- 69 min
- Issued by
- NWS Billings, MT
- Area
- Whole counties
Counties Treasure County, MT, Yellowstone County, MT
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| Jun 21, 4:45 PM MDT | Hail 1.75 | Yellowstone, MT | |
| Jun 21, 5:40 PM MDT | Tornado F1 | Yellowstone, 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. Storm Data before 1996 records only tornadoes, thunderstorm wind and hail.
The nearest sounding before it
Great Falls, MT (KGTF), launched 12:00Z, 10.6 hours before the alert went out and 311 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1217 m above ground
- 0-6 km bulk shear
- 60 kt
- 0-1 km storm-relative helicity
- 1 m²/s²
- 0-3 km storm-relative helicity
- 59 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
The text of this product is not in the archive. The NWS text archive before 2002 is incomplete.
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.
In the hours before
Special weather statement, Jun 21, 1:48 PM MDT, 2 hours 48 minutes before
WYZ003-004-005-212300- SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE SHERIDAN WY 150 PM MDT WED JUN 21 1991 ...A SEVERE THUNDERSTORM WATCH IS IN EFFECT FOR SHERIDAN AND JONHSON COUNTIES UNTIL 8 PM MDT THIS EVENING... AT 130 PM MDT RADAR SHOWED THUNDERSTORMS STARTING TO DEVELOP IN NORTH CENTRAL WYOMING. AT THIS TIME NO SEVERE WEATHER HAS BEEN REPORTED. THE STRONGEST OF THESE STORMS IS SOUTH OF SHERIDAN ABOUT 25 MILES MOVING NORTHEAST. ,PERSONS IN NORTH CENRAL WYOMING SHOULD KEEP AN EYE ON THE WEATHER AND IF THREATENING WEATHER IS SIGHT GO TO A SAFE PLACE. ZEGLIN
The office that day
Everything else NWS Billings, MT issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 21, 4:11 PM MDT | Flash Flood Warning | BYZ | Golden Valley, Musselshell | 64 min |
| Jun 21, 4:11 PM MDT | Severe Thunderstorm Warning | BYZ | Golden Valley, Musselshell | 64 min |
| Jun 21, 4:36 PM MDT | Flash Flood Warning | BYZ | Treasure, Yellowstone | 69 min |
| Jun 21, 4:43 PM MDT | Tornado Warning | BYZ | Yellowstone | 32 min |
| Jun 21, 5:01 PM MDT | Tornado Warning | BYZ | Big Horn | 29 min |
| Jun 21, 5:37 PM MDT | Tornado Warning | BYZ | Big Horn | 38 min |
| Jun 21, 5:55 PM MDT | Tornado Warning | BYZ | Rosebud | 65 min |
Nearby
Severe Thunderstorm Warnings in Montana, 1991Every severe thunderstorm warning in 1991
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.