Alert archive / Montana / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 36, NWS Great Falls, MT

July 7, 2021Fergus County, Judith Basin County, Montana

NWS Great Falls, MT issued this severe thunderstorm warning at Jul 7, 2021, 6:10 PM MDT for Fergus County, Judith Basin County, Montana. It was in force for 35 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Jul 7, 2021, 6:10 PM MDT (00:10 UTC)
Expired
Jul 7, 2021, 6:45 PM MDT
In force
35 min
Issued by
NWS Great Falls, MT
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties Fergus County, MT, Judith Basin County, MT

The radar

The Great Falls radar (KTFX), 148 km from the middle of the area, began a volume at 00:10 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.

The watch it was issued in

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

IssuedProductOfficeLasted
Jul 7, 3:03 PM MDTSevere Thunderstorm WatchSPC8 hr

The nearest sounding before it

Great_falls, MT (KTFX), launched 00:00Z, 0.2 hours before the alert went out and 92 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 2021-07-08Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 17 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 2021-07-08The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 301 square meters per square second.19395878Sfc1 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
17 J/kg
Mixed-layer CIN
-372 J/kg
Mixed-layer LCL
2303 m above ground
0-6 km bulk shear
62 kt
0-1 km storm-relative helicity
301 m²/s²
0-3 km storm-relative helicity
511 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

665 
WUUS55 KTFX 080010
SVRTFX
MTC027-045-080045-
/O.NEW.KTFX.SV.W.0036.210708T0010Z-210708T0045Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Great Falls MT
610 PM MDT Wed Jul 7 2021

The National Weather Service in Great Falls has issued a

* Severe Thunderstorm Warning for...
  East central Judith Basin County in central Montana...
  Central Fergus County in central Montana...

* Until 645 PM MDT.

* At 608 PM MDT, severe thunderstorms were located along a line
  extending from 9 miles northwest of Lewistown to near Hobson,
  moving east at 25 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.

* Locations impacted include...
  Lewistown, Hobson, Moore, Moccasin, Giltedge, Ackley Lake State
  Park and Glengarry.

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 4724 10888 4690 10967 4696 11000 4703 11001
      4722 10955
TIME...MOT...LOC 0008Z 270DEG 16KT 4718 10953 4701 10994 

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

Kredensor
2 follow-up statements
033 
WWUS55 KTFX 080031
SVSTFX

Severe Weather Statement
National Weather Service Great Falls MT
631 PM MDT Wed Jul 7 2021

MTC027-045-080045-
/O.CON.KTFX.SV.W.0036.000000T0000Z-210708T0045Z/
Judith Basin MT-Fergus MT-
631 PM MDT Wed Jul 7 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 645 PM MDT
FOR EAST CENTRAL JUDITH BASIN AND SOUTH CENTRAL FERGUS COUNTIES...

At 631 PM MDT, severe thunderstorms were located along a line
extending from 8 miles north of Lewistown to near Hobson, moving east
at 25 mph.

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

SOURCE...Radar indicated.

IMPACT...Expect damage to roofs, siding, and trees.

Locations impacted include...
Lewistown, Hobson, Moore, Giltedge and Glengarry. 

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 4724 10890 4691 10967 4697 11000 4722 10944
      4724 10898
TIME...MOT...LOC 0031Z 270DEG 16KT 4718 10939 4701 10980 

HAIL...0.75IN
WIND...60MPH
 
$$

Kredensor
770 
WWUS55 KTFX 080045
SVSTFX

Severe Weather Statement
National Weather Service Great Falls MT
645 PM MDT Wed Jul 7 2021

MTC027-045-080055-
/O.EXP.KTFX.SV.W.0036.000000T0000Z-210708T0045Z/
Judith Basin MT-Fergus MT-
645 PM MDT Wed Jul 7 2021

...THE SEVERE THUNDERSTORM WARNING FOR EAST CENTRAL JUDITH BASIN AND
SOUTH CENTRAL FERGUS COUNTIES HAS EXPIRED...
            
The storms which prompted the warning have weakened below severe
limits, and no longer pose an immediate threat to life or property.
Therefore, the warning has been allowed to expire.  However gusty
winds are still possible with these thunderstorms.

A Severe Thunderstorm Watch remains in effect until 1100 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 4724 10890 4691 10967 4697 11000 4722 10944
      4724 10898
TIME...MOT...LOC 0045Z 270DEG 16KT 4718 10930 4701 10971 

$$

Kredensor

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 7, 6:36 PM MDTSpecial Weather StatementTFX24 min
Jul 7, 6:56 PM MDTSpecial Weather StatementTFXPetroleum34 min
Jul 7, 8:02 PM MDTSpecial Weather StatementTFXGlacier28 min
Jul 7, 8:48 PM MDTSpecial Weather StatementTFXGlacier27 min
Jul 7, 9:33 PM MDTSpecial Weather StatementTFXGlacier27 min
Jul 8, 11:48 AM MDTSpecial Weather StatementTFXBlaine42 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.