Alert archive / Montana / Severe Thunderstorm Watches in 2003

Severe Thunderstorm Watch 848

August 6, 200310 counties in Montana

The Storm Prediction Center issued this severe thunderstorm watch at Aug 6, 2003, 4:50 PM MDT for 10 counties in Montana. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued
Aug 6, 2003, 4:50 PM MDT (22:50 UTC)
Expired
Aug 6, 2003, 10:00 PM MDT
In force
5 hr
Issued by
the Storm Prediction Center

Counties Blaine County, MT, Broadwater County, MT, Fergus County, MT, Golden Valley County, MT, Judith Basin County, MT, Meagher County, MT, Musselshell County, MT, Petroleum County, MT, Phillips County, MT, Wheatland County, MT

The radar

The Great Falls radar (KTFX), 138 km from the middle of the area, began a volume at 22:53 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

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

IssuedProductOfficeCountiesLasted
Aug 6, 4:54 PM MDTSevere Thunderstorm WarningTFXBlaine36 min
Aug 6, 5:06 PM MDTSevere Thunderstorm WarningTFXBlaine39 min
Aug 6, 5:09 PM MDTSevere Thunderstorm WarningTFXFergus51 min
Aug 6, 5:21 PM MDTSevere Thunderstorm WarningGGWPhillips54 min
Aug 6, 5:35 PM MDTSevere Thunderstorm WarningTFXBlaine25 min
Aug 6, 5:45 PM MDTSevere Thunderstorm WarningTFXBlaine30 min
Aug 6, 6:00 PM MDTSevere Thunderstorm WarningTFXFergus60 min
Aug 6, 6:14 PM MDTSevere Thunderstorm WarningGGWPhillips61 min
Aug 6, 7:16 PM MDTSevere Thunderstorm WarningGGWPhillips59 min
Aug 6, 7:26 PM MDTSevere Thunderstorm WarningBYZGolden Valley64 min
Aug 6, 8:12 PM MDTSevere Thunderstorm WarningGGWGarfield, Petroleum, Phillips, Valley63 min
Aug 6, 8:20 PM MDTSevere Thunderstorm WarningBYZMusselshell55 min
Aug 6, 8:30 PM MDTSevere Thunderstorm WarningGGWGarfield, Phillips, Valley60 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, 10.8 hours before the alert went out and 80 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 2003-08-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 23 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 2003-08-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 13 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
23 J/kg
Mixed-layer CIN
-474 J/kg
Mixed-layer LCL
2186 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
13 m²/s²
0-3 km storm-relative helicity
42 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
Aug 6, 1:10 PM MDTMesoscale DiscussionSPCDeer Lodge, Granite, Jefferson, Lake, Lewis and Clark, Mineral and 5 more3 hr
Aug 6, 2:10 PM MDTSevere Thunderstorm WatchSPCBeaverhead, Cascade, Deer Lodge, Flathead, Glacier, Granite and 12 more7 hr
Aug 6, 4:27 PM MDTMesoscale DiscussionSPCBlaine, Daniels, Dawson, Garfield, McCone, Phillips and 4 more2 hr
Aug 6, 5:41 PM MDTMesoscale DiscussionSPCBeaverhead, Cascade, Deer Lodge, Flathead, Glacier, Granite and 12 more2 hr

Nearby

Severe Thunderstorm Watches in Montana, 2003Every severe thunderstorm watch in 2003

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.