Alert archive / Montana / Severe Thunderstorm Watches in 2011

Severe Thunderstorm Watch 590

July 3, 201129 counties in Montana

The Storm Prediction Center issued this severe thunderstorm watch at Jul 3, 2011, 4:08 PM MDT for 29 counties in Montana. It was in force for 8 hr.

The area

The outline as issued.

The facts

Issued
Jul 3, 2011, 4:08 PM MDT (22:08 UTC)
Expired
Jul 3, 2011, 11:38 PM MDT
In force
8 hr
Issued by
the Storm Prediction Center
Largest hail expected
2 in
Strongest gust expected
70 kt
All 29 counties

Big Horn County, MT, Blaine County, MT, Carbon County, MT, Carter County, MT, Chouteau County, MT, Custer County, MT, Dawson County, MT, Fallon County, MT, Fergus County, MT, Gallatin County, MT, Garfield County, MT, Golden Valley County, MT, Hill County, MT, Judith Basin County, MT, McCone County, MT, Meagher County, MT, Musselshell County, MT, Park County, MT, Petroleum County, MT, Phillips County, MT, Powder River County, MT, Prairie County, MT, Rosebud County, MT, Stillwater County, MT, Sweet Grass County, MT, Treasure County, MT, Valley County, MT, Wheatland County, MT, Yellowstone County, MT

The radar

The Billings radar (KBLX), 103 km from the middle of the area, began a volume at 22:10 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
2%
Ten or more severe wind reports
80%
One or more gusts of 65 knots or more
50%
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
95%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Jul 3, 5:53 PM MDTSevere Thunderstorm WarningBYZCarbon, Stillwater, Yellowstone52 min
Jul 3, 6:18 PM MDTSevere Thunderstorm WarningBYZBig Horn, Treasure, Yellowstone57 min
Jul 3, 6:39 PM MDTSevere Thunderstorm WarningBYZMusselshell, Rosebud, Treasure, Yellowstone36 min
Jul 3, 7:05 PM MDTSevere Thunderstorm WarningGGWPhillips, Valley55 min
Jul 3, 7:14 PM MDTSevere Thunderstorm WarningBYZBig Horn, Rosebud, Treasure43 min
Jul 3, 7:30 PM MDTSevere Thunderstorm WarningGGWPhillips60 min
Jul 3, 7:55 PM MDTSevere Thunderstorm WarningGGWPhillips, Valley65 min
Jul 3, 7:58 PM MDTSevere Thunderstorm WarningGGWDaniels, Phillips, Valley62 min
Jul 3, 8:35 PM MDTSevere Thunderstorm WarningBYZCuster, Powder River, Rosebud55 min
Jul 3, 8:54 PM MDTSevere Thunderstorm WarningGGWPhillips, Valley66 min
Jul 3, 9:04 PM MDTSevere Thunderstorm WarningBYZCarter, Custer, Fallon, Powder River56 min
Jul 3, 9:39 PM MDTSevere Thunderstorm WarningBYZCuster, Rosebud51 min
Jul 3, 9:51 PM MDTSevere Thunderstorm WarningBYZCarter, Custer, Fallon54 min
Jul 3, 10:25 PM MDTSevere Thunderstorm WarningBYZCuster, Rosebud52 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, 10.1 hours before the alert went out and 134 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, Great_falls, MT at 12:00Z on 2011-07-03Temperature 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, Great_falls, MT at 12:00Z on 2011-07-03The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -12 square meters per square second.19395878Sfc1 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
2139 m above ground
0-6 km bulk shear
35 kt
0-1 km storm-relative helicity
-12 m²/s²
0-3 km storm-relative helicity
140 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 2, 6:48 PM MDTMesoscale DiscussionSPCCarter, Custer, Fallon, Powder River117 min
Jul 3, 12:31 PM MDTMesoscale DiscussionSPCBlaine, Broadwater, Cascade, Chouteau, Custer, Fergus and 19 more2 hr

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.