Alert archive / Montana / Severe Thunderstorm Warnings in 1998

Severe Thunderstorm Warning 87, NWS Great Falls, MT

August 21, 1998Blaine County, Montana

NWS Great Falls, MT issued this severe thunderstorm warning at Aug 21, 1998, 4:23 AM MDT for Blaine County, Montana. It was in force for 47 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Aug 21, 1998, 4:23 AM MDT (10:23 UTC)
Expired
Aug 21, 1998, 5:10 AM MDT
In force
47 min
Issued by
NWS Great Falls, MT
Area
Whole counties

County Blaine County, MT

The radar

The Glasgow radar (KGGW), 174 km from the middle of the area, began a volume at 10:26 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.

The nearest sounding before it

Great_falls, MT (KTFX), launched 00:00Z, 10.4 hours before the alert went out and 163 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 00:00Z on 1998-08-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 365 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 00:00Z on 1998-08-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 45 square meters per square second.19395878Sfc1 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
365 J/kg
Mixed-layer CIN
-74 J/kg
Mixed-layer LCL
2966 m above ground
0-6 km bulk shear
37 kt
0-1 km storm-relative helicity
45 m²/s²
0-3 km storm-relative helicity
132 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.8

Open this sounding in Storm Lab

The text

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

665 
WUUS1 KGTF 211028 RRA
SVRGTF
MTC005-211110-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE GREAT FALLS MT
423 AM MDT FRI AUG 21 1998


THE NATIONAL WEATHER SERVICE HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTH CENTRAL BLAINE COUNTY IN NORTH CENTRAL MONTANA

* UNTIL 510 AM MDT

* AT 421 AM MDT... DOPPLER RADAR AT GREAT FALLS INDICATED A SEVERE
  THUNDERSTORM IN THE VICINITY OF HARLEM MOVING NORTH AT 30 MPH.

* SOME LOCATIONS IN OR NEAR THE PATH OF THIS STORM ARE...   FORT
  BELKNAP AND HOGELAND.

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

In the hours before

Local storm report, Aug 20, 10:50 PM MDT, 5 hours 33 minutes before
STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS, MT
1050 PM MDT THU AUG 20 1998

TIME(MDT)  ......CITY LOCATION...... MT   ...EVENT.............
DATE(MDT)  ......COUNTY LOCATION....      ...REMARKS...........

0548 PM    10 S GREAT FALLS          MT   60 MPH WIND GUST
08/20/98   CASCADE

0910 PM    GREAT FALLS               MT   0.75 INCH HAIL
08/20/98   CASCADE

JB
Local storm report, Aug 20, 10:50 PM MDT, 5 hours 33 minutes before
STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS, MT
1050 PM MDT THU AUG 20 1998

TIME(MDT)  ......CITY LOCATION...... MT   ...EVENT.............
DATE(MDT)  ......COUNTY LOCATION....      ...REMARKS...........

0548 PM    10 S GREAT FALLS          MT   60 MPH WIND GUST
08/20/98   CASCADE

0910 PM    GREAT FALLS               MT   0.75 INCH HAIL
08/20/98   CASCADE

JB

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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.