Alert archive / Montana / Severe Thunderstorm Warnings in 1998

Severe Thunderstorm Warning 89, NWS Great Falls, MT

August 23, 1998Cascade County, Montana

NWS Great Falls, MT issued this severe thunderstorm warning at Aug 23, 1998, 4:17 PM MDT for Cascade County, Montana. It was in force for 58 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 23, 1998, 4:17 PM MDT (22:17 UTC)
Expired
Aug 23, 1998, 5:15 PM MDT
In force
58 min
Issued by
NWS Great Falls, MT
Area
Whole counties

County Cascade County, MT

The radar

The Great Falls radar (KTFX), 17 km from the middle of the area, began a volume at 22:18 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 23, 4:50 PM MDTThunderstorm Wind 50Cascade, 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, 10.3 hours before the alert went out and 59 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 1998-08-23Temperature 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 1998-08-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 20 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
2124 m above ground
0-6 km bulk shear
36 kt
0-1 km storm-relative helicity
20 m²/s²
0-3 km storm-relative helicity
95 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

815 
WUUS1 KGTF 232219 RRA
SVRGTF
MTC013-232315-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE GREAT FALLS MT
417 PM MDT SUN AUG 23 1998


THE NATIONAL WEATHER SERVICE HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  CASCADE COUNTY IN CENTRAL MONTANA

* UNTIL 515 PM MDT

* AT 415 PM MDT... DOPPLER RADAR AT GREAT FALLS INDICATED A RAPIDLY
  DEVELOPING THUNDERSTORM 18 MILES SOUTHWEST OF GREAT FALLS OR 12
  MILES SOUTH OF ULM MOVING NORTHEAST AT 25 MPH.

* SOME LOCATIONS IN OR NEAR THE PATH OF THIS STORM ARE...ULM...
   GREAT FALLS...   STOCKETT...   BLACK EAGLE AND   SAND COULEE.

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 23, 5:01 PM MDTSevere Thunderstorm WarningTFXCascade59 min
Aug 23, 5:08 PM MDTSevere Thunderstorm WarningTFXChouteau, Fergus, Judith Basin62 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.