Alert archive / Montana / Severe Thunderstorm Watches in 2008

Severe Thunderstorm Watch 657

July 4, 200816 counties in Montana

The Storm Prediction Center issued this severe thunderstorm watch at Jul 4, 2008, 3:05 PM MDT for 16 counties in Montana. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued
Jul 4, 2008, 3:05 PM MDT (21:05 UTC)
Expired
Jul 4, 2008, 10:00 PM MDT
In force
7 hr
Issued by
the Storm Prediction Center
Largest hail expected
2 in
Strongest gust expected
60 kt

Counties Blaine County, MT, Fergus County, MT, Gallatin County, MT, Garfield County, MT, Golden Valley County, MT, Judith Basin County, MT, McCone County, MT, Meagher County, MT, Musselshell County, MT, Park County, MT, Petroleum County, MT, Phillips County, MT, Stillwater County, MT, Sweet Grass County, MT, Valley County, MT, Wheatland County, MT

The radar

The Billings radar (KBLX), 129 km from the middle of the area, began a volume at 21:05 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
10%
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
40%
One or more hailstones of 2 inches or more
20%
Six or more combined severe hail and wind reports
90%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Jul 4, 4:10 PM MDTSevere Thunderstorm WarningTFXChouteau, Fergus, Judith Basin50 min
Jul 4, 4:10 PM MDTSevere Thunderstorm WarningTFXJudith Basin, Meagher25 min
Jul 4, 4:38 PM MDTSevere Thunderstorm WarningTFXJudith Basin67 min
Jul 4, 5:06 PM MDTSevere Thunderstorm WarningTFXCascade, Meagher39 min
Jul 4, 5:18 PM MDTSevere Thunderstorm WarningTFXFergus40 min
Jul 4, 5:23 PM MDTSevere Thunderstorm WarningTFXFergus, Judith Basin34 min
Jul 4, 5:45 PM MDTSevere Thunderstorm WarningTFXCascade, Meagher45 min
Jul 4, 6:02 PM MDTSevere Thunderstorm WarningTFXChouteau, Fergus, Judith Basin43 min
Jul 4, 6:07 PM MDTSevere Thunderstorm WarningTFXCascade, Judith Basin38 min
Jul 4, 6:27 PM MDTSevere Thunderstorm WarningTFXCascade, Chouteau, Judith Basin, Lewis and Clark, Teton48 min
Jul 4, 6:28 PM MDTSevere Thunderstorm WarningGGWPetroleum43 min
Jul 4, 6:47 PM MDTSevere Thunderstorm WarningTFXChouteau, Judith Basin25 min
Jul 4, 6:54 PM MDTSevere Thunderstorm WarningGGWGarfield, Petroleum, Phillips66 min
Jul 4, 6:58 PM MDTSevere Thunderstorm WarningTFXCascade, Chouteau, Fergus, Judith Basin, Teton47 min
Jul 4, 7:42 PM MDTSevere Thunderstorm WarningTFXBlaine, Chouteau, Hill, Liberty63 min
Jul 4, 7:57 PM MDTSevere Thunderstorm WarningGGWGarfield, Phillips, Valley24 min
Jul 4, 8:08 PM MDTSevere Thunderstorm WarningGGWGarfield, Phillips, Valley37 min
Jul 4, 8:36 PM MDTSevere Thunderstorm WarningTFXBlaine, Hill39 min
Jul 4, 9:15 PM MDTSevere Thunderstorm WarningGGWGarfield, McCone35 min
Jul 4, 9:15 PM MDTSevere Thunderstorm WarningTFXBlaine, Hill45 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, 9.1 hours before the alert went out and 110 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 2008-07-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 32 joules per kilogram.LCLLFCEL10008507005003002001001 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 2008-07-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 132 square meters per square second.193958Sfc1 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
32 J/kg
Mixed-layer CIN
-527 J/kg
Mixed-layer LCL
2745 m above ground
0-6 km bulk shear
39 kt
0-1 km storm-relative helicity
132 m²/s²
0-3 km storm-relative helicity
109 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 4, 1:45 PM MDTMesoscale DiscussionSPCBeaverhead, Broadwater, Cascade, Chouteau, Deer Lodge, Flathead and 15 more60 min
Jul 4, 2:04 PM MDTSevere Thunderstorm WatchSPCBeaverhead, Broadwater, Cascade, Chouteau, Deer Lodge, Flathead and 15 more8 hr
Jul 4, 3:02 PM MDTMesoscale DiscussionSPCBlaine, Carbon, Fergus, Golden Valley, Judith Basin, Musselshell and 7 more58 min
Jul 4, 5:45 PM MDTMesoscale DiscussionSPCBeaverhead, Blaine, Broadwater, Cascade, Chouteau, Deer Lodge and 28 more60 min

Nearby

Severe Thunderstorm Watches in Montana, 2008Every severe thunderstorm watch in 2008

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.