Alert archive / Montana / Tornado Watches in 1999

Tornado Watch 539

July 7, 199918 counties in Montana

The Storm Prediction Center issued this tornado watch at Jul 7, 1999, 6:15 PM MDT for 18 counties in Montana. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
Jul 7, 1999, 6:15 PM MDT (00:15 UTC)
Expired
Jul 8, 1999, 12:00 AM MDT
In force
6 hr
Issued by
the Storm Prediction Center

Counties Big Horn County, MT, Carter County, MT, Custer County, MT, Daniels County, MT, Dawson County, MT, Fallon County, MT, Garfield County, MT, McCone County, MT, Phillips County, MT, Powder River County, MT, Prairie County, MT, Richland County, MT, Roosevelt County, MT, Rosebud County, MT, Sheridan County, MT, Treasure County, MT, Valley County, MT, Wibaux County, MT

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Jul 7, 6:24 PM MDTSevere Thunderstorm WarningGGWPhillips, Valley61 min
Jul 7, 6:37 PM MDTSevere Thunderstorm WarningBYZPowder River33 min
Jul 7, 6:57 PM MDTSevere Thunderstorm WarningBYZCarter48 min
Jul 7, 7:23 PM MDTSevere Thunderstorm WarningGGWValley57 min
Jul 7, 7:41 PM MDTSevere Thunderstorm WarningGGWGarfield, McCone64 min
Jul 7, 8:46 PM MDTSevere Thunderstorm WarningGGWMcCone49 min
Jul 7, 9:26 PM MDTSevere Thunderstorm WarningGGWDawson64 min
Jul 7, 10:29 PM MDTSevere Thunderstorm WarningGGWRichland56 min

The nearest sounding before it

Glasgow Intl Airport, MT (KGGW), launched 00:00Z, 0.3 hours before the alert went out and 83 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 00:00Z on 1999-07-08Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1255 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, Glasgow Intl Airport, MT at 00:00Z on 1999-07-08The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 475 square meters per square second.1939587897Sfc1 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
1255 J/kg
Mixed-layer CIN
-191 J/kg
Mixed-layer LCL
1320 m above ground
0-6 km bulk shear
77 kt
0-1 km storm-relative helicity
475 m²/s²
0-3 km storm-relative helicity
855 m²/s²
Significant tornado parameter
0.0
Supercell composite
26.8

Open this sounding in Storm Lab

The text

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

Nearby

Tornado Watches in Montana, 1999Every tornado watch in 1999

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.