Alert archive / Montana / Severe Thunderstorm Warnings in 1999

Severe Thunderstorm Warning 20, NWS Great Falls, MT

June 21, 1999Judith Basin County, Montana

NWS Great Falls, MT issued this severe thunderstorm warning at Jun 21, 1999, 4:31 PM MDT for Judith Basin County, Montana. It was in force for 29 min. 3 reports came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued
Jun 21, 1999, 4:31 PM MDT (22:31 UTC)
Expired
Jun 21, 1999, 5:00 PM MDT
In force
29 min
Issued by
NWS Great Falls, MT
Area
Whole counties; the outline is the Mesonet’s reconstruction

County Judith Basin County, MT

What was reported inside it

TimeReportWhereRemark
Jun 21, 4:33 PM MDTThunderstorm Wind 61Stanford, MT
Jun 21, 4:44 PM MDTThunderstorm Wind 69Windham, MT
Jun 21, 5:09 PM MDTThunderstorm Wind 69Moccasin, MT

NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Jun 21, 3:00 PM MDTSevere Thunderstorm WatchSPC6 hr

The nearest sounding before it

Great_falls, MT (KTFX), launched 12:00Z, 10.5 hours before the alert went out and 52 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.

The office that day

Everything else NWS Great Falls, MT issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jun 21, 2:52 PM MDTSevere Thunderstorm WarningTFXGallatin33 min
Jun 21, 4:56 PM MDTSevere Thunderstorm WarningTFXFergus, Judith Basin64 min
Jun 21, 5:05 PM MDTSevere Thunderstorm WarningTFXFergus25 min
Jun 21, 5:50 PM MDTSevere Thunderstorm WarningTFXFergus25 min

Nearby

Severe Thunderstorm Warnings in Montana, 1999Every severe thunderstorm warning 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; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive.