Alert archive / Montana / Severe Thunderstorm Watches in 2011
Severe Thunderstorm Watch 642
The Storm Prediction Center issued this severe thunderstorm watch at Jul 14, 2011, 1:56 PM MDT for 29 counties in Montana. It was in force for 9 hr.
The area
The outline as issued.
The facts
- Issued
- Jul 14, 2011, 1:56 PM MDT (19:56 UTC)
- Expired
- Jul 14, 2011, 11:00 PM MDT
- In force
- 9 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2.5 in
- Strongest gust expected
- 60 kt
All 29 counties
Big Horn County, MT, Blaine County, MT, Carbon County, MT, Carter County, MT, Custer County, MT, Daniels County, MT, Dawson County, MT, Fallon County, MT, Fergus County, MT, Garfield County, MT, Golden Valley County, MT, McCone County, MT, Musselshell County, MT, Park County, MT, Petroleum County, MT, Phillips County, MT, Powder River County, MT, Prairie County, MT, Richland County, MT, Roosevelt County, MT, Rosebud County, MT, Sheridan County, MT, Stillwater County, MT, Sweet Grass County, MT, Treasure County, MT, Valley County, MT, Wheatland County, MT, Wibaux County, MT, Yellowstone County, MT
The radar
The Glasgow radar (KGGW), 133 km from the middle of the area, began a volume at 19:57 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.
What SPC expected
The probabilities SPC published with the watch, for the watch area over its life.
- Two or more tornadoes
- 20%
- One or more EF2 to EF5 tornadoes
- 5%
- Ten or more severe wind reports
- 40%
- One or more gusts of 65 knots or more
- 30%
- Ten or more severe hail reports
- 30%
- One or more hailstones of 2 inches or more
- 50%
- Six or more combined severe hail and wind reports
- 80%
Warnings issued inside it
33 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 14, 3:44 PM MDT | Severe Thunderstorm Warning | BYZ | Golden Valley, Wheatland | 40 min |
| Jul 14, 3:53 PM MDT | Severe Thunderstorm Warning | TFX | Fergus | 52 min |
| Jul 14, 4:07 PM MDT | Severe Thunderstorm Warning | BYZ | Carbon, Stillwater, Yellowstone | 38 min |
| Jul 14, 4:29 PM MDT | Severe Thunderstorm Warning | BYZ | Yellowstone | 61 min |
| Jul 14, 4:59 PM MDT | Tornado Warning | BYZ | Yellowstone | 31 min |
| Jul 14, 5:13 PM MDT | Severe Thunderstorm Warning | BYZ | Yellowstone | 62 min |
| Jul 14, 5:27 PM MDT | Severe Thunderstorm Warning | BYZ | Big Horn | 63 min |
| Jul 14, 5:30 PM MDT | Severe Thunderstorm Warning | BYZ | Musselshell, Yellowstone | 60 min |
| Jul 14, 5:35 PM MDT | Severe Thunderstorm Warning | BYZ | Golden Valley, Stillwater, Yellowstone | 33 min |
| Jul 14, 5:52 PM MDT | Severe Thunderstorm Warning | GGW | Garfield, Phillips | 53 min |
| Jul 14, 6:01 PM MDT | Severe Thunderstorm Warning | BYZ | Treasure, Yellowstone | 59 min |
| Jul 14, 6:09 PM MDT | Severe Thunderstorm Warning | BYZ | Musselshell, Rosebud | 51 min |
| Jul 14, 6:26 PM MDT | Severe Thunderstorm Warning | GGW | Phillips, Valley | 64 min |
| Jul 14, 6:28 PM MDT | Severe Thunderstorm Warning | BYZ | Big Horn, Treasure | 62 min |
| Jul 14, 6:43 PM MDT | Severe Thunderstorm Warning | GGW | Garfield | 62 min |
| Jul 14, 6:59 PM MDT | Severe Thunderstorm Warning | BYZ | Rosebud, Treasure | 31 min |
| Jul 14, 7:14 PM MDT | Severe Thunderstorm Warning | GGW | Valley | 61 min |
| Jul 14, 7:16 PM MDT | Severe Thunderstorm Warning | BYZ | Big Horn, Rosebud, Treasure | 59 min |
| Jul 14, 7:19 PM MDT | Flash Flood Warning | GGW | Garfield | 3 hr |
| Jul 14, 7:45 PM MDT | Severe Thunderstorm Warning | BYZ | Custer, Rosebud | 60 min |
| Jul 14, 7:58 PM MDT | Severe Thunderstorm Warning | GGW | Garfield, McCone, Prairie | 62 min |
| Jul 14, 8:02 PM MDT | Severe Thunderstorm Warning | BYZ | Custer, Powder River, Rosebud | 58 min |
| Jul 14, 8:42 PM MDT | Severe Thunderstorm Warning | GGW | Dawson, McCone | 63 min |
| Jul 14, 8:44 PM MDT | Severe Thunderstorm Warning | GGW | Roosevelt, Valley | 61 min |
| Jul 14, 8:59 PM MDT | Severe Thunderstorm Warning | BYZ | Custer | 61 min |
| Jul 14, 9:17 PM MDT | Severe Thunderstorm Warning | BYZ | Rosebud | 58 min |
| Jul 14, 9:33 PM MDT | Severe Thunderstorm Warning | GGW | Dawson, Prairie, Wibaux | 57 min |
| Jul 14, 9:40 PM MDT | Severe Thunderstorm Warning | BYZ | Carter, Custer, Fallon | 50 min |
| Jul 14, 9:44 PM MDT | Severe Thunderstorm Warning | GGW | Daniels, Roosevelt, Sheridan | 61 min |
| Jul 14, 10:16 PM MDT | Severe Thunderstorm Warning | BYZ | Rosebud | 29 min |
| Jul 14, 10:29 PM MDT | Flash Flood Warning | BYZ | Rosebud | 3 hr |
| Jul 14, 10:29 PM MDT | Severe Thunderstorm Warning | BYZ | Fallon | 46 min |
| Jul 14, 10:29 PM MDT | Severe Thunderstorm Warning | GGW | Dawson, Wibaux | 46 min |
Discussions around it
SPC mesoscale discussions over the same counties from four hours before the watch to its end.
The nearest sounding before it
Great_falls, MT (KTFX), launched 12:00Z, 7.9 hours before the alert went out and 200 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
- 88 J/kg
- Mixed-layer CIN
- -148 J/kg
- Mixed-layer LCL
- 1371 m above ground
- 0-6 km bulk shear
- 31 kt
- 0-1 km storm-relative helicity
- -25 m²/s²
- 0-3 km storm-relative helicity
- 88 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- -0.0
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 13, 7:33 PM MDT | Mesoscale Discussion | SPC | Blaine, Cascade, Chouteau, Fergus, Flathead, Glacier and 8 more | 57 min |
| Jul 14, 11:04 AM MDT | Mesoscale Discussion | SPC | Blaine, Fergus, Golden Valley, Judith Basin, Meagher, Musselshell and 5 more | 116 min |
Nearby
Severe Thunderstorm Watches in Montana, 2011Every severe thunderstorm watch in 2011
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.