Alert archive / Montana / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 40, NWS Great Falls, MT

July 11, 2021Liberty County, Toole County, Montana

NWS Great Falls, MT issued this severe thunderstorm warning at Jul 11, 2021, 4:18 PM MDT for Liberty County, Toole County, Montana. It was in force for 27 min. 2 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: Jul 11, 2021, 4:18 PM MDT (22:18 UTC)
Expired: Jul 11, 2021, 4:45 PM MDT
In force: 27 min
Issued by: NWS Great Falls, MT
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Liberty County, MT, Toole County, MT

The radar

The Great Falls radar (KTFX), 98 km from the middle of the area, began a volume at 22:22 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
Jul 11, 4:30 PM MDT	TSTM WND DMG	8 Ese Lothair, MT	SWING SET BLOWN AWAY, MANY TREES HAD SIGNIFICANT NUMBER OF LIMBS BLOWN OFF.
Jul 11, 4:34 PM MDT	TSTM WND GST 64	10 Nne Galata, MT

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

The nearest sounding before it

Great_falls, MT (KTFX), launched 12:00Z, 10.3 hours before the alert went out and 104 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: 3738 m above ground
0-6 km bulk shear: 21 kt
0-1 km storm-relative helicity: -10 m²/s²
0-3 km storm-relative helicity: 104 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

003 
WUUS55 KTFX 112218
SVRTFX
MTC051-101-112245-
/O.NEW.KTFX.SV.W.0040.210711T2218Z-210711T2245Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Great Falls MT
418 PM MDT Sun Jul 11 2021

The National Weather Service in Great Falls has issued a

* Severe Thunderstorm Warning for...
  Southern Liberty County in north central Montana...
  Southeastern Toole County in north central Montana...

* Until 445 PM MDT.

* At 416 PM MDT, a severe thunderstorm was located 7 miles west of
  Lothair, or 19 miles west of Chester, moving east at 55 mph.

  HAZARD...60 mph wind gusts and quarter size hail. Severe wind 
           gusts may occur well to the south and southwest of the 
           main storm.

  SOURCE...Radar indicated.

  IMPACT...Hail damage to vehicles is expected. Expect wind damage 
           to roofs, siding, and trees.

* Locations impacted include...
  Chester, Joplin, Lothair, Tiber Dam, Devon and Galata. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

If on or near Lake Elwell, get away from the water and move indoors 
or inside a vehicle. Remember, lightning can strike out to 15 miles 
from the parent thunderstorm. If you can hear thunder, you are close 
enough to be struck by lightning. Move to safe shelter now!  Do not 
be caught on the water in a thunderstorm.

&&

LAT...LON 4861 11075 4822 11075 4821 11083 4813 11083
      4813 11140 4822 11141 4822 11157 4824 11161
      4863 11140
TIME...MOT...LOC 2216Z 286DEG 48KT 4849 11139 

HAIL...1.00IN
WIND...60MPH
 
$$

HART

2 follow-up statements

382 
WWUS55 KTFX 112234
SVSTFX

Severe Weather Statement
National Weather Service Great Falls MT
434 PM MDT Sun Jul 11 2021

MTC051-101-112245-
/O.CON.KTFX.SV.W.0040.000000T0000Z-210711T2245Z/
Liberty MT-Toole MT-
434 PM MDT Sun Jul 11 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 445 PM MDT
FOR SOUTHERN LIBERTY AND SOUTHEASTERN TOOLE COUNTIES...

At 432 PM MDT, a severe thunderstorm was located 7 miles southwest of
Chester, moving east at 55 mph.

HAZARD...60 mph wind gusts and quarter size hail. Severe wind gusts 
         may occur well to the south and southwest of the main storm.

SOURCE...Radar indicated.

IMPACT...Hail damage to vehicles is expected. Expect wind damage to 
         roofs, siding, and trees.

Locations impacted include...
Chester, Joplin, Lothair, Tiber Dam, Devon and Galata. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Frequent 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.

&&

LAT...LON 4861 11075 4822 11075 4821 11083 4813 11083
      4813 11140 4822 11141 4822 11157 4824 11161
      4863 11140
TIME...MOT...LOC 2232Z 286DEG 48KT 4843 11106 

HAIL...1.00IN
WIND...60MPH
 
$$

HART

347 
WWUS55 KTFX 112245
SVSTFX

Severe Weather Statement
National Weather Service Great Falls MT
445 PM MDT Sun Jul 11 2021

MTC051-101-112253-
/O.EXP.KTFX.SV.W.0040.000000T0000Z-210711T2245Z/
Liberty MT-Toole MT-
445 PM MDT Sun Jul 11 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHERN LIBERTY AND
SOUTHEASTERN TOOLE COUNTIES WILL EXPIRE AT 445 PM MDT...
                
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning will be allowed to expire.  However small 
hail up to nickel size and gusty winds of 50 to 55 mph are still 
possible with this thunderstorm.

LAT...LON 4861 11075 4822 11075 4821 11083 4813 11083
      4813 11140 4822 11141 4822 11157 4824 11161
      4863 11140
TIME...MOT...LOC 2243Z 286DEG 48KT 4839 11085 

$$

HART

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 11, 12:33 AM MDT	Red Flag Warning	TFX	Blaine, Broadwater, Cascade, Chouteau, Fergus, Gallatin and 12 more	20 hr
Jul 11, 2:18 PM MDT	Special Weather Statement	TFX	Glacier	42 min
Jul 11, 2:28 PM MDT	Severe Thunderstorm Warning	TFX	Glacier	50 min
Jul 11, 2:58 PM MDT	Special Weather Statement	TFX	Glacier	32 min
Jul 11, 3:03 PM MDT	Severe Thunderstorm Warning	TFX	Glacier, Toole	42 min
Jul 11, 3:40 PM MDT	Severe Thunderstorm Warning	TFX	Toole	50 min
Jul 11, 4:36 PM MDT	Special Weather Statement	TFX	Pondera	24 min
Jul 11, 4:47 PM MDT	Special Weather Statement	TFX	Chouteau	28 min
Jul 11, 5:05 PM MDT	Special Weather Statement	TFX	Pondera	25 min
Jul 11, 5:11 PM MDT	Severe Thunderstorm Warning	TFX	Chouteau, Hill	49 min
Jul 11, 5:55 PM MDT	Severe Thunderstorm Warning	TFX	Blaine, Chouteau, Hill	65 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.