Alert archive / Montana / Tornado Watches in 1999

Tornado Watch 459

June 21, 19998 counties in Montana

The Storm Prediction Center issued this tornado watch at Jun 21, 1999, 5:30 PM MDT for 8 counties in Montana. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
Jun 21, 1999, 5:30 PM MDT (23:30 UTC)
Expired
Jun 21, 1999, 11:00 PM MDT
In force
6 hr
Issued by
the Storm Prediction Center

Counties Blaine County, MT, Daniels County, MT, McCone County, MT, Phillips County, MT, Richland County, MT, Roosevelt County, MT, Sheridan County, MT, Valley County, MT

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Jun 21, 5:41 PM MDTSevere Thunderstorm WarningGGWPhillips64 min
Jun 21, 6:38 PM MDTSevere Thunderstorm WarningGGWPhillips62 min
Jun 21, 6:51 PM MDTSevere Thunderstorm WarningGGWValley59 min
Jun 21, 6:56 PM MDTSevere Thunderstorm WarningGGWMcCone64 min
Jun 21, 7:17 PM MDTSevere Thunderstorm WarningGGWPhillips63 min
Jun 21, 7:40 PM MDTTornado WarningGGWPhillips, Valley65 min
Jun 21, 7:52 PM MDTSevere Thunderstorm WarningGGWDaniels, Roosevelt63 min
Jun 21, 8:28 PM MDTTornado WarningGGWRoosevelt62 min
Jun 21, 8:30 PM MDTSevere Thunderstorm WarningGGWMcCone, Richland60 min
Jun 21, 8:44 PM MDTSevere Thunderstorm WarningGGWSheridan61 min
Jun 21, 8:55 PM MDTSevere Thunderstorm WarningGGWDaniels35 min

The nearest sounding before it

Great_falls, MT (KTFX), launched 12:00Z, 11.5 hours before the alert went out and 271 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 1999-06-21Temperature 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 1999-06-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 58 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1908 m above ground
0-6 km bulk shear
36 kt
0-1 km storm-relative helicity
58 m²/s²
0-3 km storm-relative helicity
202 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

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.

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jun 20, 9:00 PM MDTSevere Thunderstorm WatchSPCCarter, Custer, Fallon, Powder River4 hr
Jun 21, 3:00 PM MDTSevere Thunderstorm WatchSPCBig Horn, Carbon, Carter, Custer, Dawson, Fallon and 17 more6 hr

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.