Alert archive / Montana / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 13, NWS Great Falls, MT

June 9, 2021Blaine County, Montana

NWS Great Falls, MT issued this severe thunderstorm warning at Jun 9, 2021, 10:48 PM MDT for Blaine 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
Jun 9, 2021, 10:48 PM MDT (04:48 UTC)
Expired
Jun 9, 2021, 11:30 PM MDT
In force
42 min
Issued by
NWS Great Falls, MT
Area
Storm-based polygon
Hail
1.75 in
Wind
60.0 mph

County Blaine County, MT

The radar

The Glasgow radar (KGGW), 154 km from the middle of the area, began a volume at 04:50 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 9, 10:55 PM MDTHAIL 1.5Hays, MTQUARTER TO PING PONG BALL SIZED HAIL REPORTED IN HAYS, MT WITH THE THIRD SYSTEM THAT TRACKED THROUGH THE AREA, GUSTY WINDS THAT SHOOK THE TRUCK, ESTIMATED 50 MPH GUSTS.

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.

IssuedProductOfficeLasted
Jun 9, 6:42 PM MDTSevere Thunderstorm WatchSPC5 hr

The nearest sounding before it

Great_falls, MT (KTFX), launched 00:00Z, 4.8 hours before the alert went out and 156 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 00:00Z on 2021-06-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 22 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 00:00Z on 2021-06-10The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 12 square meters per square second.1939587897Sfc1 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
22 J/kg
Mixed-layer CIN
-195 J/kg
Mixed-layer LCL
1287 m above ground
0-6 km bulk shear
71 kt
0-1 km storm-relative helicity
12 m²/s²
0-3 km storm-relative helicity
408 m²/s²
Significant tornado parameter
-0.0
Supercell composite
-0.1

Open this sounding in Storm Lab

The text

As transmitted.

005 
WUUS55 KTFX 100448
SVRTFX
MTC005-100530-
/O.NEW.KTFX.SV.W.0013.210610T0448Z-210610T0530Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Great Falls MT
1048 PM MDT Wed Jun 9 2021

The National Weather Service in Great Falls has issued a

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

* Until 1130 PM MDT.

* At 1048 PM MDT, a severe thunderstorm was located 7 miles southwest
  of Hays, or 12 miles west of Zortman, moving north at 25 mph.

  HAZARD...Golf 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...
  Hays and Lodge Pole. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Prepare immediately for large hail and deadly cloud to ground
lightning. Seek shelter inside a well-built structure. 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.

&&

LAT...LON 4798 10862 4792 10864 4793 10879 4792 10885
      4794 10894 4832 10884 4823 10842 4797 10844
TIME...MOT...LOC 0448Z 201DEG 21KT 4794 10879 

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

Kredensor
3 follow-up statements
195 
WWUS55 KTFX 100506
SVSTFX

Severe Weather Statement
National Weather Service Great Falls MT
1106 PM MDT Wed Jun 9 2021

MTC005-100530-
/O.CON.KTFX.SV.W.0013.000000T0000Z-210610T0530Z/
Blaine MT-
1106 PM MDT Wed Jun 9 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1130 PM MDT
FOR SOUTHEASTERN BLAINE COUNTY...

At 1106 PM MDT, a severe thunderstorm was located near Hays, or 13
miles northwest of Zortman, moving north at 30 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...
Hays.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Prepare immediately for large hail and deadly cloud to ground
lightning. Seek shelter inside a well-built structure. 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.

&&

LAT...LON 4793 10864 4799 10892 4811 10890 4832 10884
      4823 10844 4798 10858 4798 10862
TIME...MOT...LOC 0506Z 192DEG 25KT 4804 10874 

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

Kredensor
745 
WWUS55 KTFX 100521
SVSTFX

Severe Weather Statement
National Weather Service Great Falls MT
1121 PM MDT Wed Jun 9 2021

MTC005-100530-
/O.CON.KTFX.SV.W.0013.000000T0000Z-210610T0530Z/
Blaine MT-
1121 PM MDT Wed Jun 9 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1130 PM MDT
FOR EAST CENTRAL BLAINE COUNTY...

At 1120 PM MDT, a severe thunderstorm was located 10 miles north of
Hays, or 17 miles northwest of Zortman, moving north at 30 mph.

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

SOURCE...Radar indicated.

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

This severe thunderstorm will remain over mainly rural areas of east
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 4803 10859 4809 10887 4832 10883 4823 10846
TIME...MOT...LOC 0520Z 193DEG 25KT 4814 10870 

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

Kredensor
816 
WWUS55 KTFX 100535
SVSTFX

Severe Weather Statement
National Weather Service Great Falls MT
1135 PM MDT Wed Jun 9 2021

MTC005-100544-
/O.EXP.KTFX.SV.W.0013.000000T0000Z-210610T0530Z/
Blaine MT-
1135 PM MDT Wed Jun 9 2021

...THE SEVERE THUNDERSTORM WARNING FOR EAST CENTRAL BLAINE COUNTY HAS
EXPIRED...
    
The severe thunderstorm which prompted the warning has weakened. 
Therefore, the warning was allowed to expire.  However small hail 
and gusty winds are still possible with this thunderstorm.

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

LAT...LON 4803 10859 4809 10887 4832 10883 4823 10846
TIME...MOT...LOC 0534Z 201DEG 21KT 4822 10866 

$$

Kredensor

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 9, 6:18 PM MDTSevere Thunderstorm WarningTFXBlaine42 min
Jun 9, 6:55 PM MDTSevere Thunderstorm WarningTFXBlaine35 min
Jun 9, 7:08 PM MDTSpecial Weather StatementTFXFergus22 min
Jun 9, 7:19 PM MDTSpecial Weather StatementTFXTeton56 min
Jun 9, 7:26 PM MDTSpecial Weather StatementTFXFergus34 min
Jun 9, 7:28 PM MDTSpecial Weather StatementTFXJudith Basin32 min
Jun 9, 7:36 PM MDTSpecial Weather StatementTFXFergus24 min
Jun 9, 7:53 PM MDTSevere Thunderstorm WarningTFXChouteau, Fergus37 min
Jun 9, 7:57 PM MDTSpecial Weather StatementTFXHill33 min
Jun 9, 8:04 PM MDTSpecial Weather StatementTFXJudith Basin26 min
Jun 9, 8:19 PM MDTSpecial Weather StatementTFXTeton26 min
Jun 9, 8:28 PM MDTSevere Thunderstorm WarningTFXChouteau, Judith Basin32 min
Jun 9, 8:31 PM MDTSpecial Weather StatementTFXChouteau29 min
Jun 9, 8:42 PM MDTSevere Thunderstorm WarningTFXBlaine, Fergus33 min
Jun 9, 8:45 PM MDTSpecial Weather StatementTFXPetroleum30 min
Jun 9, 8:48 PM MDTSpecial Weather StatementTFXHill27 min
Jun 9, 8:57 PM MDTSpecial Weather StatementTFXBlaine18 min
Jun 9, 9:04 PM MDTSevere Thunderstorm WarningTFXChouteau, Hill26 min
Jun 9, 9:09 PM MDTSevere Thunderstorm WarningTFXBlaine, Fergus21 min
Jun 9, 9:18 PM MDTSpecial Weather StatementTFXToole42 min
Jun 9, 9:26 PM MDTSpecial Weather StatementTFXBlaine49 min
Jun 9, 9:30 PM MDTSevere Thunderstorm WarningTFXBlaine45 min
Jun 9, 9:37 PM MDTSpecial Weather StatementTFXBlaine23 min
Jun 9, 9:38 PM MDTSpecial Weather StatementTFXFergus37 min
Jun 9, 9:38 PM MDTSevere Thunderstorm WarningTFXBlaine40 min
Jun 9, 9:51 PM MDTSpecial Weather StatementTFXBlaine24 min
Jun 9, 10:17 PM MDTSpecial Weather StatementTFXBlaine28 min
Jun 9, 10:32 PM MDTSpecial Weather StatementTFXFergus43 min
Jun 9, 11:34 PM MDTSpecial Weather StatementTFXBlaine, Fergus, Hill116 min
Jun 10, 2:11 AM MDTSpecial Weather StatementTFXBlaine34 min
Jun 10, 2:53 PM MDTSpecial Weather StatementTFXFergus37 min
Jun 10, 3:08 PM MDTSevere Thunderstorm WarningTFXFergus52 min
Jun 10, 3:53 PM MDTSpecial Weather StatementTFXFergus37 min
Jun 10, 4:22 PM MDTSpecial Weather StatementTFXCascade23 min
Jun 10, 4:56 PM MDTSpecial Weather StatementTFXCascade34 min
Jun 10, 5:33 PM MDTSpecial Weather StatementTFXCascade27 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.