Alert archive / Montana / Severe Thunderstorm Watches in 2011

Severe Thunderstorm Watch 419

June 2, 201114 counties in Montana

The Storm Prediction Center issued this severe thunderstorm watch at Jun 2, 2011, 2:09 PM MDT for 14 counties in Montana. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued
Jun 2, 2011, 2:09 PM MDT (20:09 UTC)
Expired
Jun 2, 2011, 9:00 PM MDT
In force
7 hr
Issued by
the Storm Prediction Center
Largest hail expected
2 in
Strongest gust expected
60 kt

Counties Custer County, MT, Daniels County, MT, Dawson County, MT, Fallon County, MT, Garfield County, MT, McCone County, MT, Phillips County, MT, Prairie County, MT, Richland County, MT, Roosevelt County, MT, Rosebud County, MT, Sheridan County, MT, Valley County, MT, Wibaux County, MT

The radar

The Glasgow radar (KGGW), 38 km from the middle of the area, began a volume at 20:10 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
30%
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
20%
Six or more combined severe hail and wind reports
80%

Warnings issued inside it

12 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
Jun 2, 2:16 PM MDTSevere Thunderstorm WarningGGWGarfield, Phillips, Valley59 min
Jun 2, 2:20 PM MDTSevere Thunderstorm WarningGGWGarfield43 min
Jun 2, 2:23 PM MDTSevere Thunderstorm WarningGGWPhillips, Valley52 min
Jun 2, 2:40 PM MDTSevere Thunderstorm WarningGGWPhillips, Valley49 min
Jun 2, 3:06 PM MDTSevere Thunderstorm WarningGGWPhillips, Valley39 min
Jun 2, 3:09 PM MDTSevere Thunderstorm WarningBYZCuster, Rosebud45 min
Jun 2, 3:10 PM MDTSevere Thunderstorm WarningGGWValley65 min
Jun 2, 3:49 PM MDTSevere Thunderstorm WarningGGWPrairie29 min
Jun 2, 3:50 PM MDTSevere Thunderstorm WarningGGWGarfield, McCone, Valley25 min
Jun 2, 4:08 PM MDTSevere Thunderstorm WarningGGWGarfield, McCone, Roosevelt, Valley52 min
Jun 2, 4:46 PM MDTSevere Thunderstorm WarningGGWDawson, Prairie24 min
Jun 2, 4:49 PM MDTFlash Flood WarningGGWValley3 hr

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Glasgow Intl Airport, MT (KGGW), launched 12:00Z, 8.2 hours before the alert went out and 38 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, Glasgow Intl Airport, MT at 12:00Z on 2011-06-02Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Glasgow Intl Airport, MT at 12:00Z on 2011-06-02The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 22 square meters per square second.1939587897117Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
736 m above ground
0-6 km bulk shear
58 kt
0-1 km storm-relative helicity
22 m²/s²
0-3 km storm-relative helicity
201 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.1

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jun 2, 1:54 PM MDTMesoscale DiscussionSPCCuster, Daniels, Dawson, Fallon, Garfield, McCone and 6 more66 min
Jun 2, 4:37 PM MDTMesoscale DiscussionSPCDaniels, Dawson, Richland, Roosevelt, Sheridan, Wibaux83 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.