Alert archive / Montana / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 35, NWS Great Falls, MT

July 7, 2021Blaine County, Montana

NWS Great Falls, MT issued this severe thunderstorm warning at Jul 7, 2021, 5:38 PM MDT for Blaine County, Montana. It was in force for 37 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Jul 7, 2021, 5:38 PM MDT (23:38 UTC)
Expired: Jul 7, 2021, 6:15 PM MDT
In force: 37 min
Issued by: NWS Great Falls, MT
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

County Blaine County, MT

The radar

The Glasgow radar (KGGW), 178 km from the middle of the area, began a volume at 23:42 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 12:00Z, 11.6 hours before the alert went out and 131 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: 42 J/kg
Mixed-layer CIN: -360 J/kg
Mixed-layer LCL: 2232 m above ground
0-6 km bulk shear: 36 kt
0-1 km storm-relative helicity: -61 m²/s²
0-3 km storm-relative helicity: 70 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

019 
WUUS55 KTFX 072338
SVRTFX
MTC005-080015-
/O.NEW.KTFX.SV.W.0035.210707T2338Z-210708T0015Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Great Falls MT
538 PM MDT Wed Jul 7 2021

The National Weather Service in Great Falls has issued a

* Severe Thunderstorm Warning for...
  South central Blaine County in north central Montana...

* Until 615 PM MDT.

* At 538 PM MDT, a severe thunderstorm was located 21 miles west of
  Hays, or 27 miles west of Zortman, moving southeast at 25 mph.

  HAZARD...60 mph wind gusts and penny size hail.

  SOURCE...Radar indicated.

  IMPACT...Expect damage to roofs, siding, and trees.

* This severe thunderstorm will remain over mainly rural areas of
  south central Blaine County.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 4792 10889 4774 10890 4779 10895 4781 10898
      4780 10903 4793 10929 4810 10907 4793 10870
TIME...MOT...LOC 2338Z 303DEG 23KT 4797 10911 

HAIL...0.75IN
WIND...60MPH
 
$$

CMC

2 follow-up statements

333 
WWUS55 KTFX 072357
SVSTFX

Severe Weather Statement
National Weather Service Great Falls MT
557 PM MDT Wed Jul 7 2021

MTC005-080015-
/O.CON.KTFX.SV.W.0035.000000T0000Z-210708T0015Z/
Blaine MT-
557 PM MDT Wed Jul 7 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 615 PM MDT
FOR SOUTH CENTRAL BLAINE COUNTY...

At 557 PM MDT, a severe thunderstorm was located 15 miles southwest
of Hays, or 19 miles west of Zortman, moving southeast at 25 mph.

HAZARD...60 mph wind gusts and penny size hail.

SOURCE...Radar indicated.

IMPACT...Expect damage to roofs, siding, and trees.

This severe thunderstorm will remain over mainly rural areas of south
central Blaine County.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

To report severe weather contact your nearest law enforcement agency.
They will send your report to the National Weather Service office in
Great Falls.

&&

LAT...LON 4786 10912 4803 10895 4797 10879 4793 10870
      4792 10889 4774 10890 4779 10895 4781 10898
      4780 10902
TIME...MOT...LOC 2357Z 303DEG 23KT 4790 10896 

HAIL...0.75IN
WIND...60MPH
 
$$

Kredensor

303 
WWUS55 KTFX 080016
SVSTFX

Severe Weather Statement
National Weather Service Great Falls MT
616 PM MDT Wed Jul 7 2021

MTC005-080025-
/O.EXP.KTFX.SV.W.0035.000000T0000Z-210708T0015Z/
Blaine MT-
616 PM MDT Wed Jul 7 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTH CENTRAL BLAINE COUNTY
HAS EXPIRED...
        
The storm which prompted the warning has moved out of the area.
Therefore, the warning has been allowed to expire.

A Severe Thunderstorm Watch remains in effect until 1100 PM MDT for
central Montana.

To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
Great Falls.

LAT...LON 4786 10912 4803 10895 4797 10879 4793 10870
      4792 10889 4774 10890 4779 10895 4781 10898
      4780 10902
TIME...MOT...LOC 0015Z 303DEG 23KT 4784 10882 

$$

Kredensor

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 6, 6:14 PM MDT	Severe Thunderstorm Warning	TFX	Blaine	29 min
Jul 6, 6:16 PM MDT	Special Weather Statement	TFX	Toole	29 min
Jul 6, 6:50 PM MDT	Severe Thunderstorm Warning	TFX	Blaine	40 min
Jul 6, 6:57 PM MDT	Special Weather Statement	TFX	Toole	33 min
Jul 6, 7:27 PM MDT	Severe Thunderstorm Warning	TFX	Blaine	63 min
Jul 6, 7:30 PM MDT	Special Weather Statement	TFX	Liberty	30 min
Jul 6, 8:20 PM MDT	Tornado Warning	TFX	Blaine	25 min
Jul 6, 8:45 PM MDT	Severe Thunderstorm Warning	TFX	Blaine	19 min
Jul 7, 1:51 PM MDT	Special Weather Statement	TFX	Beaverhead	39 min
Jul 7, 2:03 PM MDT	Special Weather Statement	TFX	Judith Basin	27 min
Jul 7, 2:18 PM MDT	Special Weather Statement	TFX	Fergus	27 min
Jul 7, 2:43 PM MDT	Special Weather Statement	TFX	Fergus	32 min
Jul 7, 2:46 PM MDT	Severe Thunderstorm Warning	TFX	Fergus	29 min
Jul 7, 2:55 PM MDT	Special Weather Statement	TFX	Madison	50 min
Jul 7, 3:06 PM MDT	Special Weather Statement	TFX	Jefferson	54 min
Jul 7, 3:13 PM MDT	Severe Thunderstorm Warning	TFX	Fergus	47 min
Jul 7, 3:21 PM MDT	Special Weather Statement	TFX	Fergus	24 min
Jul 7, 3:26 PM MDT	Severe Thunderstorm Warning	TFX	Jefferson, Lewis and Clark	34 min
Jul 7, 3:36 PM MDT	Special Weather Statement	TFX	Fergus	24 min
Jul 7, 3:40 PM MDT	Special Weather Statement	TFX	Lewis and Clark	35 min
Jul 7, 3:46 PM MDT	Special Weather Statement	TFX	Broadwater, Jefferson	44 min
Jul 7, 3:55 PM MDT	Special Weather Statement	TFX	Gallatin	50 min
Jul 7, 3:59 PM MDT	Special Weather Statement	TFX	Fergus	46 min
Jul 7, 4:02 PM MDT	Special Weather Statement	TFX	Broadwater, Jefferson	43 min
Jul 7, 4:30 PM MDT	Severe Thunderstorm Warning	TFX	Gallatin	30 min
Jul 7, 4:36 PM MDT	Severe Thunderstorm Warning	TFX	Gallatin	15 min
Jul 7, 4:48 PM MDT	Special Weather Statement	TFX	Silver Bow	27 min
Jul 7, 4:56 PM MDT	Special Weather Statement	TFX	Meagher	34 min
Jul 7, 5:12 PM MDT	Special Weather Statement	TFX	Judith Basin	48 min
Jul 7, 5:13 PM MDT	Special Weather Statement	TFX	Blaine	62 min
Jul 7, 5:56 PM MDT	Special Weather Statement	TFX	Blaine	34 min

Nearby

Severe Thunderstorm Warnings in Montana, 2021 Every severe thunderstorm warning in 2021

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.