Alert archive / Montana / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 17, NWS Great Falls, MT

June 24, 2021Fergus County, Montana

NWS Great Falls, MT issued this severe thunderstorm warning at Jun 24, 2021, 5:29 PM MDT for Fergus County, Montana. It was in force for 31 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 24, 2021, 5:29 PM MDT (23:29 UTC)
Expired
Jun 24, 2021, 6:00 PM MDT
In force
31 min
Issued by
NWS Great Falls, MT
Area
Storm-based polygon
Hail
1.25 in
Wind
60.0 mph

County Fergus County, MT

The radar

The Billings radar (KBLX), 111 km from the middle of the area, began a volume at 23:31 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
Jun 24, 5:35 PM MDTTSTM WND GST 5913 Sse Forestgrove, MTAWOS STATION KMVH N BAR RANCH AWOS. TIME ESTIMATED BASED ON RADAR.

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, 11.5 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-pSkew-T log-p diagram, Great_falls, MT at 12:00Z on 2021-06-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 10 joules per kilogram.LCLLFCEL10008507005003002001001 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 2021-06-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 105 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
10 J/kg
Mixed-layer CIN
-138 J/kg
Mixed-layer LCL
2437 m above ground
0-6 km bulk shear
20 kt
0-1 km storm-relative helicity
105 m²/s²
0-3 km storm-relative helicity
109 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

532 
WUUS55 KTFX 242329
SVRTFX
MTC027-250000-
/O.NEW.KTFX.SV.W.0017.210624T2329Z-210625T0000Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Great Falls MT
529 PM MDT Thu Jun 24 2021

The National Weather Service in Great Falls has issued a

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

* Until 600 PM MDT.

* At 528 PM MDT, a severe thunderstorm was located 18 miles southeast
  of Lewistown, moving east at 35 mph.

  HAZARD...60 mph wind gusts and half dollar size hail.

  SOURCE...Radar indicated.

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

* Locations impacted include...
  Grass Range and Forestgrove. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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.

&&

LAT...LON 4676 10863 4675 10868 4675 10914 4677 10928
      4702 10921 4703 10861
TIME...MOT...LOC 2328Z 278DEG 29KT 4687 10916 

HAIL...1.25IN
WIND...60MPH
 
$$

Ludwig
1 follow-up statement
683 
WWUS55 KTFX 242348
SVSTFX

Severe Weather Statement
National Weather Service Great Falls MT
548 PM MDT Thu Jun 24 2021

MTC027-250000-
/O.CON.KTFX.SV.W.0017.000000T0000Z-210625T0000Z/
Fergus MT-
548 PM MDT Thu Jun 24 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 600 PM MDT
FOR SOUTHEASTERN FERGUS COUNTY...

At 547 PM MDT, a severe thunderstorm was located 14 miles southwest
of Grass Range, or 26 miles southeast of Lewistown, moving east at 35
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.

This severe thunderstorm will remain over mainly rural areas of
southeastern Fergus County.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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.

&&

LAT...LON 4675 10868 4679 10904 4698 10899 4700 10861
      4676 10863
TIME...MOT...LOC 2347Z 278DEG 29KT 4685 10896 

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

Ludwig

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 24, 2:05 PM MDTSpecial Weather StatementTFXCascade40 min
Jun 24, 3:57 PM MDTSpecial Weather StatementTFXTeton33 min
Jun 24, 4:07 PM MDTSpecial Weather StatementTFXMeagher23 min
Jun 24, 4:25 PM MDTSpecial Weather StatementTFXTeton35 min
Jun 24, 4:29 PM MDTSevere Thunderstorm WarningTFXFergus, Judith Basin31 min
Jun 24, 4:55 PM MDTSevere Thunderstorm WarningTFXFergus, Judith Basin35 min
Jun 24, 5:16 PM MDTSpecial Weather StatementTFXFergus44 min
Jun 24, 5:59 PM MDTSevere Thunderstorm WarningTFXFergus31 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.