Alert archive / Montana / Severe Thunderstorm Watches in 2002
Severe Thunderstorm Watch 657
The Storm Prediction Center issued this severe thunderstorm watch at Aug 31, 2002, 4:05 PM MDT for 13 counties in Montana. It was in force for 5 hr.
The area
The outline as issued.
The facts
- Issued
- Aug 31, 2002, 4:05 PM MDT (22:05 UTC)
- Expired
- Aug 31, 2002, 9:00 PM MDT
- In force
- 5 hr
- Issued by
- the Storm Prediction Center
Counties Big Horn County, MT, Carter County, MT, Custer County, MT, Dawson County, MT, Fallon County, MT, Garfield County, MT, McCone County, MT, Powder River County, MT, Prairie County, MT, Richland County, MT, Rosebud County, MT, Treasure County, MT, Wibaux County, MT
The radar
The Glasgow radar (KGGW), 149 km from the middle of the area, began a volume at 22:06 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.
Warnings issued inside it
3 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 31, 4:53 PM MDT | Severe Thunderstorm Warning | GGW | Garfield | 67 min |
| Aug 31, 4:59 PM MDT | Severe Thunderstorm Warning | BYZ | Rosebud | 61 min |
| Aug 31, 5:54 PM MDT | Severe Thunderstorm Warning | BYZ | Custer | 51 min |
The nearest sounding before it
Glasgow Intl Airport, MT (KGGW), launched 12:00Z, 10.1 hours before the alert went out and 150 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
- 564 J/kg
- Mixed-layer CIN
- -146 J/kg
- Mixed-layer LCL
- 1144 m above ground
- 0-6 km bulk shear
- 33 kt
- 0-1 km storm-relative helicity
- -59 m²/s²
- 0-3 km storm-relative helicity
- 4 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.3
The text
As transmitted, in the capitals the NWS used until 2016.
000 WWUS20 KWNS 312203 SEL7 SPC WW 312205 MTZ000-010300- URGENT - IMMEDIATE BROADCAST REQUESTED SEVERE THUNDERSTORM WATCH NUMBER 657 STORM PREDICTION CENTER NORMAN OK 405 PM MDT SAT AUG 31 2002 THE STORM PREDICTION CENTER HAS ISSUED A SEVERE THUNDERSTORM WATCH FOR PORTIONS OF EASTERN MONTANA EFFECTIVE THIS SATURDAY AFTERNOON AND EVENING FROM 405 PM UNTIL 900 PM MDT. HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS. THE SEVERE THUNDERSTORM WATCH AREA IS ALONG AND 95 STATUTE MILES NORTH AND SOUTH OF A LINE FROM 85 MILES WEST OF MILES CITY MONTANA TO 40 MILES EAST SOUTHEAST OF GLENDIVE MONTANA. REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS AND POSSIBLE WARNINGS. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY DO PRODUCE TORNADOES. DISCUSSION...CONVECTION IS INCREASING NEAR SW/NE SURFACE FRONT AS UPPER VORTICITY MAX MOVES ENEWD ACROSS SRN MT. AIR MASS IS MODERATELY UNSTABLE WITH MLCAPE AROUND 1500 J/KG...AND 35-45 KT WSWLY MID LEVEL FLOW IS PROVIDING SUFFICIENT DEEP LAYER SHEAR TO ENHANCE SEVERE THREAT. ADDITIONAL WATCHES...THE DAKOTAS ARE BEING MONITORED FOR ANOTHER WW SHORTLY. AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM MOTION VECTOR 24035. ...WEISS 474,1073 481,1040 453,1040 450,1073
Nearby
Severe Thunderstorm Watches in Montana, 2002Every severe thunderstorm watch in 2002
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; radar from the NEXRAD Level II archive.