Alert archive / Montana / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 38, NWS Great Falls, MT

July 11, 2021Glacier County, Toole County, Montana

NWS Great Falls, MT issued this severe thunderstorm warning at Jul 11, 2021, 3:03 PM MDT for Glacier County, Toole County, Montana. It was in force for 42 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
Jul 11, 2021, 3:03 PM MDT (21:03 UTC)
Expired
Jul 11, 2021, 3:45 PM MDT
In force
42 min
Issued by
NWS Great Falls, MT
Area
Storm-based polygon
Hail
1.5 in
Wind
70.0 mph

Counties Glacier County, MT, Toole County, MT

The radar

The Great Falls radar (KTFX), 153 km from the middle of the area, began a volume at 21:07 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

TimeReportWhereRemark
Jul 11, 3:24 PM MDTTSTM WND DMGCut Bank, MTPOWER LINES DOWN IN CUT BANK WITH A HIGH NUMBER OF POWER OUTAGES. ALSO REPORTED A TREE WAS DOWNED.

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, 9.1 hours before the alert went out and 185 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 12:00Z on 2021-07-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Great_falls, MT at 12:00Z on 2021-07-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -10 square meters per square second.193958Sfc1 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
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.

285 
WUUS55 KTFX 112103
SVRTFX
MTC035-101-112145-
/O.NEW.KTFX.SV.W.0038.210711T2103Z-210711T2145Z/

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

The National Weather Service in Great Falls has issued a

* Severe Thunderstorm Warning for...
  East central Glacier County in north central Montana...
  West central Toole County in north central Montana...

* Until 345 PM MDT.

* At 302 PM MDT, a severe thunderstorm was located 16 miles northwest
  of Cut Bank, moving southeast at 45 mph.

  HAZARD...70 mph wind gusts and ping pong ball size hail.

  SOURCE...Radar indicated.

  IMPACT...People and animals outdoors will be injured. Expect hail 
           damage to roofs, siding, windows, and vehicles. Expect 
           considerable tree damage. Wind damage is also likely to 
           mobile homes, roofs, and outbuildings.

* Locations impacted include...
  Shelby, Cut Bank, Kevin, Ethridge, Oilmont and Santa Rita. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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.

&&

LAT...LON 4875 11266 4892 11242 4870 11165 4840 11189
TIME...MOT...LOC 2102Z 300DEG 41KT 4882 11254 

HAIL...1.50IN
WIND...70MPH
 
$$

HART
2 follow-up statements
618 
WWUS55 KTFX 112124
SVSTFX

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

MTC035-101-112145-
/O.CON.KTFX.SV.W.0038.000000T0000Z-210711T2145Z/
Glacier MT-Toole MT-
324 PM MDT Sun Jul 11 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 345 PM MDT
FOR EAST CENTRAL GLACIER AND WEST CENTRAL TOOLE COUNTIES...

At 323 PM MDT, a severe thunderstorm was located near Cut Bank,
moving southeast at 45 mph.

HAZARD...Ping pong ball size hail and 60 mph wind gusts.

SOURCE...Radar indicated.

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

Locations impacted include...
Shelby, Kevin, Ethridge, Oilmont and Santa Rita. 

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 4874 11250 4889 11231 4870 11165 4840 11189
TIME...MOT...LOC 2123Z 299DEG 39KT 4871 11224 

HAIL...1.50IN
WIND...60MPH
 
$$

HART
887 
WWUS55 KTFX 112135
SVSTFX

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

MTC035-101-112145-
/O.CON.KTFX.SV.W.0038.000000T0000Z-210711T2145Z/
Glacier MT-Toole MT-
335 PM MDT Sun Jul 11 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 345 PM MDT
FOR EAST CENTRAL GLACIER AND WEST CENTRAL TOOLE COUNTIES...

At 334 PM MDT, a severe thunderstorm was located 8 miles southwest of
Kevin, or 11 miles east of Cut Bank, moving southeast at 45 mph.

HAZARD...Golf ball size hail and 60 mph wind gusts.

SOURCE...Radar indicated. A 60 mph wind gust was also recently 
         measured at the Cut Bank airport.

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

Locations impacted include...
Shelby, Kevin, Ethridge and Oilmont. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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.

&&

LAT...LON 4866 11235 4885 11218 4870 11165 4840 11189
TIME...MOT...LOC 2134Z 299DEG 39KT 4865 11209 

HAIL...1.75IN
WIND...60MPH
 
$$

HART

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 11, 12:33 AM MDTRed Flag WarningTFXBlaine, Broadwater, Cascade, Chouteau, Fergus, Gallatin and 12 more20 hr
Jul 11, 2:18 PM MDTSpecial Weather StatementTFXGlacier42 min
Jul 11, 2:28 PM MDTSevere Thunderstorm WarningTFXGlacier50 min
Jul 11, 2:58 PM MDTSpecial Weather StatementTFXGlacier32 min
Jul 11, 3:40 PM MDTSevere Thunderstorm WarningTFXToole50 min
Jul 11, 4:18 PM MDTSevere Thunderstorm WarningTFXLiberty, Toole27 min
Jul 11, 4:36 PM MDTSpecial Weather StatementTFXPondera24 min
Jul 11, 4:47 PM MDTSpecial Weather StatementTFXChouteau28 min
Jul 11, 5:05 PM MDTSpecial Weather StatementTFXPondera25 min
Jul 11, 5:11 PM MDTSevere Thunderstorm WarningTFXChouteau, Hill49 min
Jul 11, 5:55 PM MDTSevere Thunderstorm WarningTFXBlaine, Chouteau, Hill65 min

Nearby

Severe Thunderstorm Warnings in Montana, 2021Every 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.