Alert archive / Montana / Severe Thunderstorm Watches in 1998

Severe Thunderstorm Watch 739

July 11, 199820 counties in Montana

The Storm Prediction Center issued this severe thunderstorm watch at Jul 11, 1998, 3:30 PM MDT for 20 counties in Montana. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
Jul 11, 1998, 3:30 PM MDT (21:30 UTC)
Expired
Jul 11, 1998, 9:00 PM MDT
In force
6 hr
Issued by
the Storm Prediction Center

Counties Big Horn County, MT, Carbon County, MT, Carter County, MT, Custer County, MT, Fallon County, MT, Golden Valley County, MT, Judith Basin County, MT, Meagher County, MT, Musselshell County, MT, Park County, MT, Petroleum County, MT, Powder River County, MT, Prairie County, MT, Rosebud County, MT, Stillwater County, MT, Sweet Grass County, MT, Treasure County, MT, Wheatland County, MT, Wibaux County, MT, Yellowstone County, MT

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Jul 11, 3:45 PM MDTSevere Thunderstorm WarningBYZPark65 min
Jul 11, 4:03 PM MDTSevere Thunderstorm WarningBYZBig Horn62 min
Jul 11, 5:06 PM MDTSevere Thunderstorm WarningBYZBig Horn64 min
Jul 11, 6:03 PM MDTSevere Thunderstorm WarningBYZRosebud47 min
Jul 11, 6:37 PM MDTSevere Thunderstorm WarningBYZPowder River63 min

The nearest sounding before it

Great_falls, MT (KTFX), launched 12:00Z, 9.5 hours before the alert went out and 213 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 1998-07-11Temperature 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 1998-07-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 51 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
-306 J/kg
Mixed-layer LCL
1932 m above ground
0-6 km bulk shear
24 kt
0-1 km storm-relative helicity
51 m²/s²
0-3 km storm-relative helicity
52 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

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The text

The text of this product is not in the archive. The NWS text archive before 2002 is incomplete.

Nearby

Severe Thunderstorm Watches in Montana, 1998Every severe thunderstorm watch in 1998

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.