Alert archive / Montana / Severe Thunderstorm Warnings in 1998

Severe Thunderstorm Warning 77, NWS Great Falls, MT

August 7, 1998Cascade County, Chouteau County, Teton County, Montana

NWS Great Falls, MT issued this severe thunderstorm warning at Aug 7, 1998, 4:45 PM MDT for Cascade County, Chouteau County, Teton County, Montana. It was in force for 45 min. 1 report 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
Aug 7, 1998, 4:45 PM MDT (22:45 UTC)
Expired
Aug 7, 1998, 5:30 PM MDT
In force
45 min
Issued by
NWS Great Falls, MT
Area
Whole counties

Counties Cascade County, MT, Chouteau County, MT, Teton County, MT

The radar

The Great Falls radar (KTFX), 24 km from the middle of the area, began a volume at 22:45 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.

What was reported inside it

TimeReportWhereRemark
Aug 7, 4:45 PM MDTHail 1.75Dutton, 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 nearest sounding before it

Great_falls, MT (KTFX), launched 12:00Z, 10.8 hours before the alert went out and 61 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 1998-08-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 70 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 1998-08-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 90 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
70 J/kg
Mixed-layer CIN
-254 J/kg
Mixed-layer LCL
1445 m above ground
0-6 km bulk shear
34 kt
0-1 km storm-relative helicity
90 m²/s²
0-3 km storm-relative helicity
153 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
Aug 7, 3:54 PM MDTSevere Thunderstorm WarningTFXBroadwater, Jefferson, Lewis and Clark46 min
Aug 7, 4:10 PM MDTSevere Thunderstorm WarningTFXCascade, Teton35 min
Aug 7, 4:19 PM MDTSevere Thunderstorm WarningTFXPondera51 min
Aug 7, 4:51 PM MDTSevere Thunderstorm WarningTFXLewis and Clark49 min
Aug 7, 4:57 PM MDTSevere Thunderstorm WarningTFXPondera, Toole48 min
Aug 7, 5:19 PM MDTSevere Thunderstorm WarningTFXLiberty, Toole36 min
Aug 7, 5:25 PM MDTSevere Thunderstorm WarningTFXChouteau50 min
Aug 7, 5:39 PM MDTSevere Thunderstorm WarningTFXBroadwater, Meagher51 min
Aug 7, 5:39 PM MDTSevere Thunderstorm WarningTFXJefferson51 min
Aug 7, 5:48 PM MDTSevere Thunderstorm WarningTFXLiberty42 min

Nearby

Severe Thunderstorm Warnings in Montana, 1998Every severe thunderstorm warning 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; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.