Alert archive / Montana / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 21, NWS Billings, MT

July 6, 2021Big Horn County, Yellowstone County, Montana

NWS Billings, MT issued this severe thunderstorm warning at Jul 6, 2021, 5:55 PM MDT for Big Horn County, Yellowstone County, Montana. It was in force for 50 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 6, 2021, 5:55 PM MDT (23:55 UTC)
Expired: Jul 6, 2021, 6:45 PM MDT
In force: 50 min
Issued by: NWS Billings, MT
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Big Horn County, MT, Yellowstone County, MT

The radar

The Billings radar (KBLX), 32 km from the middle of the area, began a volume at 23:59 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 6, 5:56 PM MDT	HAIL 1	1 S Huntley, MT

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.

Issued	Product	Office	Lasted
Jul 6, 5:00 PM MDT	Severe Thunderstorm Watch	SPC	6 hr

The nearest sounding before it

Great_falls, MT (KTFX), launched 12:00Z, 11.9 hours before the alert went out and 261 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: 103 J/kg
Mixed-layer CIN: -251 J/kg
Mixed-layer LCL: 1154 m above ground
0-6 km bulk shear: 27 kt
0-1 km storm-relative helicity: 37 m²/s²
0-3 km storm-relative helicity: 134 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.2

Open this sounding in Storm Lab

The text

As transmitted.

810 
WUUS55 KBYZ 062355
SVRBYZ
MTC003-111-070045-
/O.NEW.KBYZ.SV.W.0021.210706T2355Z-210707T0045Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Billings MT
555 PM MDT Tue Jul 6 2021

The National Weather Service in Billings has issued a

* Severe Thunderstorm Warning for...
  North central Big Horn County in south central Montana...
  South central Yellowstone County in south central Montana...

* Until 645 PM MDT.

* At 555 PM MDT, a severe thunderstorm was located near Huntley, or
  11 miles northeast of Billings, moving southeast at 25 mph.

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

  SOURCE...Trained weather spotters.

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

* Locations impacted include...
  Shepherd and Huntley. 

This warning does not include the city of Billings.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4588 10843 4597 10830 4569 10780 4552 10809
TIME...MOT...LOC 2355Z 320DEG 23KT 4586 10832 

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

Carrothers

1 follow-up statement

971 
WWUS55 KBYZ 070024
SVSBYZ

Severe Weather Statement
National Weather Service Billings MT
624 PM MDT Tue Jul 6 2021

MTC003-111-070045-
/O.CON.KBYZ.SV.W.0021.000000T0000Z-210707T0045Z/
Big Horn MT-Yellowstone MT-
624 PM MDT Tue Jul 6 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 645 PM MDT
FOR NORTH CENTRAL BIG HORN AND SOUTH CENTRAL YELLOWSTONE COUNTIES...

At 624 PM MDT, a severe thunderstorm was located 14 miles southeast
of Huntley, or 19 miles east of Billings, moving southeast at 25 mph.

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

SOURCE...Trained weather spotters.

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 north
central Big Horn and south central Yellowstone Counties.

This warning does not include the city of Billings.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4578 10823 4586 10811 4569 10780 4556 10802
TIME...MOT...LOC 0024Z 320DEG 23KT 4572 10815 

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

Carrothers

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 6, 3:50 PM MDT	Special Weather Statement	BYZ	Golden Valley	25 min
Jul 6, 4:21 PM MDT	Severe Thunderstorm Warning	BYZ	Golden Valley, Musselshell	24 min
Jul 6, 4:43 PM MDT	Severe Thunderstorm Warning	BYZ	Golden Valley, Musselshell, Yellowstone	32 min
Jul 6, 4:43 PM MDT	Severe Thunderstorm Warning	BYZ	Musselshell, Rosebud	47 min
Jul 6, 5:12 PM MDT	Severe Thunderstorm Warning	BYZ	Yellowstone	48 min
Jul 6, 5:27 PM MDT	Severe Thunderstorm Warning	BYZ	Musselshell, Rosebud, Treasure, Yellowstone	63 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.