Alert archive / Montana / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 14, NWS Great Falls, MT

June 10, 2021Fergus County, Montana

NWS Great Falls, MT issued this severe thunderstorm warning at Jun 10, 2021, 3:08 PM MDT for Fergus County, Montana. It was in force for 52 min. 3 reports 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 10, 2021, 3:08 PM MDT (21:08 UTC)
Expired: Jun 10, 2021, 4:00 PM MDT
In force: 52 min
Issued by: NWS Great Falls, MT
Area: Storm-based polygon
Hail: 1.0 in
Wind: 50.0 mph

County Fergus County, MT

The radar

The Billings radar (KBLX), 148 km from the middle of the area, began a volume at 21:08 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 10, 3:20 PM MDT	HAIL 0.88	Grass Range, MT
Jun 10, 3:28 PM MDT	HAIL 0.75	4 Ne Grass Range, MT	REPORT FROM MPING: DIME SIZE (0.75 IN.) HAIL.
Jun 10, 3:33 PM MDT	HAIL 1	4 Ne Grass Range, MT	REPORT FROM MPING: QUARTER SIZE (1.00 IN.) HAIL.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Jun 10, 2:52 PM MDT	Severe Thunderstorm Watch	SPC	6 hr

The nearest sounding before it

Great_falls, MT (KTFX), launched 12:00Z, 9.1 hours before the alert went out and 147 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1207 m above ground
0-6 km bulk shear: 68 kt
0-1 km storm-relative helicity: 166 m²/s²
0-3 km storm-relative helicity: 685 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

685 
WUUS55 KTFX 102108
SVRTFX
MTC027-102200-
/O.NEW.KTFX.SV.W.0014.210610T2108Z-210610T2200Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Great Falls MT
308 PM MDT Thu Jun 10 2021

The National Weather Service in Great Falls has issued a

* Severe Thunderstorm Warning for...
  Southeastern Fergus County in central Montana...

* Until 400 PM MDT.

* At 308 PM MDT, a severe thunderstorm was located near Grass Range,
  or 24 miles east of Lewistown, moving north at 35 mph.

  HAZARD...Quarter size hail.

  SOURCE...Radar indicated.

  IMPACT...Damage to vehicles is expected.

* Locations impacted include...
  Grass Range, Roy, Fergus, Valentine and Forestgrove. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Prepare immediately for large hail and damaging winds. People outside
should move immediately to shelter inside a strong building. Stay
away from windows.

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

Large hail and damaging winds and continuous cloud to ground
lightning is occurring with this storm. Move indoors immediately.
Lightning is one of nature's leading killers. Remember, if you can
hear thunder, you are close enough to be struck by lightning.

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4731 10841 4731 10859 4727 10860 4727 10872
      4719 10871 4718 10874 4710 10874 4710 10862
      4708 10861 4685 10882 4687 10915 4744 10921
      4734 10838
TIME...MOT...LOC 2108Z 196DEG 30KT 4706 10891 

HAIL...1.00IN
WIND...<50MPH
 
$$

TPP

2 follow-up statements

222 
WWUS55 KTFX 102134
SVSTFX

Severe Weather Statement
National Weather Service Great Falls MT
334 PM MDT Thu Jun 10 2021

MTC027-102200-
/O.CON.KTFX.SV.W.0014.000000T0000Z-210610T2200Z/
Fergus MT-
334 PM MDT Thu Jun 10 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 400 PM MDT
FOR EAST CENTRAL FERGUS COUNTY...

At 333 PM MDT, a severe thunderstorm was located 7 miles southeast of
Roy, or 28 miles northwest of Winnett, moving north at 35 mph.

HAZARD...Ping pong ball size hail.

SOURCE...Radar indicated.

IMPACT...People and animals outdoors will be injured. Expect damage 
         to roofs, siding, windows, and vehicles.

Locations impacted include...
Roy and Fergus. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Prepare immediately for large hail and damaging winds. People outside
should move to a shelter, inside a strong building and away from
windows.

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

Continuous cloud to ground lightning is occurring with this storm.
Move indoors immediately. Lightning is one of nature's leading
killers. Remember, if you can hear thunder, you are close enough to
be struck by lightning.

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4703 10869 4706 10916 4713 10918 4744 10921
      4734 10841 4731 10844 4731 10859 4727 10860
      4727 10872 4719 10871 4718 10874 4710 10874
      4710 10863
TIME...MOT...LOC 2133Z 196DEG 30KT 4727 10882 

HAIL...1.50IN
WIND...<50MPH
 
$$

TPP

131 
WWUS55 KTFX 102155
SVSTFX

Severe Weather Statement
National Weather Service Great Falls MT
355 PM MDT Thu Jun 10 2021

MTC027-102204-
/O.EXP.KTFX.SV.W.0014.000000T0000Z-210610T2200Z/
Fergus MT-
355 PM MDT Thu Jun 10 2021

...THE SEVERE THUNDERSTORM WARNING FOR EAST CENTRAL FERGUS COUNTY
WILL EXPIRE AT 400 PM MDT...
        
The storm which prompted the warning has moved out of the area.
Therefore, the warning will be allowed to expire.  However gusty
winds and heavy rain are still possible with this thunderstorm.

A Severe Thunderstorm Watch remains in effect until 1000 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 4703 10869 4706 10916 4713 10918 4744 10921
      4734 10841 4731 10844 4731 10859 4727 10860
      4727 10872 4719 10871 4718 10874 4710 10874
      4710 10863
TIME...MOT...LOC 2154Z 196DEG 30KT 4739 10877 

$$

TPP

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 9, 6:18 PM MDT	Severe Thunderstorm Warning	TFX	Blaine	42 min
Jun 9, 6:55 PM MDT	Severe Thunderstorm Warning	TFX	Blaine	35 min
Jun 9, 7:08 PM MDT	Special Weather Statement	TFX	Fergus	22 min
Jun 9, 7:19 PM MDT	Special Weather Statement	TFX	Teton	56 min
Jun 9, 7:26 PM MDT	Special Weather Statement	TFX	Fergus	34 min
Jun 9, 7:28 PM MDT	Special Weather Statement	TFX	Judith Basin	32 min
Jun 9, 7:36 PM MDT	Special Weather Statement	TFX	Fergus	24 min
Jun 9, 7:53 PM MDT	Severe Thunderstorm Warning	TFX	Chouteau, Fergus	37 min
Jun 9, 7:57 PM MDT	Special Weather Statement	TFX	Hill	33 min
Jun 9, 8:04 PM MDT	Special Weather Statement	TFX	Judith Basin	26 min
Jun 9, 8:19 PM MDT	Special Weather Statement	TFX	Teton	26 min
Jun 9, 8:28 PM MDT	Severe Thunderstorm Warning	TFX	Chouteau, Judith Basin	32 min
Jun 9, 8:31 PM MDT	Special Weather Statement	TFX	Chouteau	29 min
Jun 9, 8:42 PM MDT	Severe Thunderstorm Warning	TFX	Blaine, Fergus	33 min
Jun 9, 8:45 PM MDT	Special Weather Statement	TFX	Petroleum	30 min
Jun 9, 8:48 PM MDT	Special Weather Statement	TFX	Hill	27 min
Jun 9, 8:57 PM MDT	Special Weather Statement	TFX	Blaine	18 min
Jun 9, 9:04 PM MDT	Severe Thunderstorm Warning	TFX	Chouteau, Hill	26 min
Jun 9, 9:09 PM MDT	Severe Thunderstorm Warning	TFX	Blaine, Fergus	21 min
Jun 9, 9:18 PM MDT	Special Weather Statement	TFX	Toole	42 min
Jun 9, 9:26 PM MDT	Special Weather Statement	TFX	Blaine	49 min
Jun 9, 9:30 PM MDT	Severe Thunderstorm Warning	TFX	Blaine	45 min
Jun 9, 9:37 PM MDT	Special Weather Statement	TFX	Blaine	23 min
Jun 9, 9:38 PM MDT	Special Weather Statement	TFX	Fergus	37 min
Jun 9, 9:38 PM MDT	Severe Thunderstorm Warning	TFX	Blaine	40 min
Jun 9, 9:51 PM MDT	Special Weather Statement	TFX	Blaine	24 min
Jun 9, 10:17 PM MDT	Special Weather Statement	TFX	Blaine	28 min
Jun 9, 10:32 PM MDT	Special Weather Statement	TFX	Fergus	43 min
Jun 9, 10:48 PM MDT	Severe Thunderstorm Warning	TFX	Blaine	42 min
Jun 9, 11:34 PM MDT	Special Weather Statement	TFX	Blaine, Fergus, Hill	116 min
Jun 10, 2:11 AM MDT	Special Weather Statement	TFX	Blaine	34 min
Jun 10, 2:53 PM MDT	Special Weather Statement	TFX	Fergus	37 min
Jun 10, 3:53 PM MDT	Special Weather Statement	TFX	Fergus	37 min
Jun 10, 4:22 PM MDT	Special Weather Statement	TFX	Cascade	23 min
Jun 10, 4:56 PM MDT	Special Weather Statement	TFX	Cascade	34 min
Jun 10, 5:33 PM MDT	Special Weather Statement	TFX	Cascade	27 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.