Alert archive / Montana / Severe Thunderstorm Warnings in 2002

Severe Thunderstorm Warning 9, NWS Great Falls, MT

June 21, 2002Jefferson County, Montana

NWS Great Falls, MT issued this severe thunderstorm warning at Jun 21, 2002, 7:45 PM MDT for Jefferson County, Montana. It was in force for 30 min. 1 report came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Jun 21, 2002, 7:45 PM MDT (01:45 UTC)
Expired: Jun 21, 2002, 8:15 PM MDT
In force: 30 min
Issued by: NWS Great Falls, MT
Area: Counties, with a storm outline in the text

County Jefferson County, MT

The radar

The Great Falls radar (KTFX), 125 km from the middle of the area, began a volume at 01:46 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

Time	Report	Where	Remark
Jun 21, 8:10 PM MDT	Thunderstorm Wind 52 E	Clancy, MT	A severe thunderstorm produced a 60 mph wind gust at Clancy 6N.

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 00:00Z, 1.8 hours before the alert went out and 158 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 354 J/kg
Mixed-layer CIN: -88 J/kg
Mixed-layer LCL: 2291 m above ground
0-6 km bulk shear: 39 kt
0-1 km storm-relative helicity: 74 m²/s²
0-3 km storm-relative helicity: 182 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.8

Open this sounding in Storm Lab

The text

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

000 
WUUS55 KTFX 220145 CCA
SVRTFX
MTC043-220215-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING...CORRECTION
NATIONAL WEATHER SERVICE GREAT FALLS MT
737 PM MDT FRI JUN 21 2002

THE NATIONAL WEATHER SERVICE IN GREAT FALLS HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTH CENTRAL JEFFERSON COUNTY IN SOUTHWEST MONTANA

* UNTIL 815 PM MDT

* AT 726 PM MDT...THE PUBLIC REPORTED A SEVERE THUNDERSTORM 
  NEAR BOULDER...MOVING NORTHEAST AT 25 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  MONTANA CITY AT 750 PM MDT

THE PUBLIC REPORTED ONE INCH HAIL AND STRONG WINDS WITH THIS STORM.

LAT...LON 4639 11221 4624 11186 4655 11181 4655 11201

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 21, 7:39 PM MDT	Severe Thunderstorm Warning	TFX	Jefferson	36 min
Jun 21, 7:59 PM MDT	Severe Thunderstorm Warning	TFX	Broadwater	31 min
Jun 21, 8:03 PM MDT	Severe Thunderstorm Warning	TFX	Cascade	42 min
Jun 21, 8:07 PM MDT	Severe Thunderstorm Warning	TFX	Lewis and Clark	23 min
Jun 21, 8:08 PM MDT	Severe Thunderstorm Warning	TFX	Cascade	37 min
Jun 21, 8:28 PM MDT	Severe Thunderstorm Warning	TFX	Meagher	32 min
Jun 21, 8:58 PM MDT	Severe Thunderstorm Warning	TFX	Meagher	47 min
Jun 21, 9:11 PM MDT	Severe Thunderstorm Warning	TFX	Cascade, Meagher	64 min
Jun 21, 9:57 PM MDT	Severe Thunderstorm Warning	TFX	Judith Basin	48 min
Jun 22, 2:49 PM MDT	Severe Thunderstorm Warning	TFX	Fergus	26 min
Jun 22, 3:20 PM MDT	Severe Thunderstorm Warning	TFX	Fergus	55 min
Jun 22, 4:19 PM MDT	Severe Thunderstorm Warning	TFX	Blaine	41 min

Nearby

Severe Thunderstorm Warnings in Montana, 2002 Every severe thunderstorm warning in 2002

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.