Alert archive / Wyoming / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 28, NWS Billings, MT

July 6, 2021Sheridan County, Wyoming

NWS Billings, MT issued this severe thunderstorm warning at Jul 6, 2021, 9:13 PM MDT for Sheridan County, Wyoming. It was in force for 30 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, 9:13 PM MDT (03:13 UTC)
Expired: Jul 6, 2021, 9:43 PM MDT
In force: 30 min
Issued by: NWS Billings, MT
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

County Sheridan County, WY

The radar

The Billings radar (KBLX), 172 km from the middle of the area, began a volume at 03:16 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, 9:35 PM MDT	HAIL 0.25	1 N Sheridan, WY

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

Did it verify

Not verified. The Iowa Environmental Mesonet's Cow found no qualifying storm report inside this severe thunderstorm warning while it was in force. That is not proof nothing happened: reports are thin where few people live.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

The nearest sounding before it

Riverton, WY (KRIW), launched 00:00Z, 3.2 hours before the alert went out and 218 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: 138 J/kg
Mixed-layer CIN: -63 J/kg
Mixed-layer LCL: 3032 m above ground
0-6 km bulk shear: 21 kt
0-1 km storm-relative helicity: -17 m²/s²
0-3 km storm-relative helicity: 59 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

795 
WUUS55 KBYZ 070313
SVRBYZ
WYC033-070415-
/O.NEW.KBYZ.SV.W.0028.210707T0313Z-210707T0415Z/

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

The National Weather Service in Billings has issued a

* Severe Thunderstorm Warning for...
  Central Sheridan County in north central Wyoming...

* Until 1015 PM MDT.

* At 912 PM MDT, a severe thunderstorm was located near Ranchester,
  or 10 miles northwest of Sheridan, moving southeast at 20 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...
  Sheridan, Ranchester, Dayton, Big Horn, Banner, Story and Ucross. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4488 10730 4498 10701 4456 10653 4456 10706
TIME...MOT...LOC 0312Z 327DEG 18KT 4487 10714 

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

Lester

1 follow-up statement

853 
WWUS55 KBYZ 070343
SVSBYZ

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

WYC033-070352-
/O.CAN.KBYZ.SV.W.0028.000000T0000Z-210707T0415Z/
Sheridan WY-
943 PM MDT Tue Jul 6 2021

...THE SEVERE THUNDERSTORM WARNING FOR CENTRAL SHERIDAN COUNTY IS
CANCELLED...
                
The storm which prompted the warning has weakened, and no longer 
poses an immediate threat to life or property. Therefore, the 
warning has been cancelled.

LAT...LON 4488 10730 4498 10701 4456 10653 4456 10706
TIME...MOT...LOC 0341Z 327DEG 18KT 4474 10702 

$$

Lester

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Billings, MT wrote its last area forecast discussion before this severe thunderstorm warning went out at Jul 6, 8:50 PM MDT, 23 minutes earlier.

Area forecast discussion, Jul 6, 8:50 PM MDT, 23 minutes before

Area Forecast Discussion
National Weather Service Billings MT
850 PM MDT Tue Jul 6 2021

.UPDATE...
Have cancelled Yellowstone, Musselshell and Treasure Counties from
the Severe Thunderstorm Watch. The risk remains for the rest of
the watch area. A couple strong to severe storms currently exist
near Lame Deer and Decker, and another is approaching northern
Rosebud County. All storms are moving from the NNW to SSE,
consistent with the expectation for right-moving supercells. JKL

&&

.DISCUSSION...
Today through Wednesday night...

Ridging to the west of the area will keep door open for
disturbances dropping in from the northwest tonight. These
disturbances will interact with a dryline/stalled front draped
across the central portion of the forecast area just east of a
Roundup to Billings to Sheridan line to produce isolated to maybe
scattered showers and thunderstorms through late tonight. Along
the boundary shear and CAPE values will support a few strong to
severe thunderstorms, with large hail, strong wind gusts and heavy
downpours. Convection will slowly shift eastward overnight but
wouldn't be surprised to see a few showers or even a lingering
thunderstorm along the eastern state line around sunrise.

Ridge axis shifts into the area tomorrow boosting temperatures to
around 100 degrees in many areas. Late in the day into the evening
hours a series of disturbances will duck under the ridge and push
through the area. Models have trended wetter with this period
bumping precipitation chances to 30-40percent for most of the area
into the late night hours. The main threat with any storms
Wednesday given the heat and lower RH values will be gusty winds
over the western half of the forecast area, further east exists
better ingredients for a strong storm but by the time the energy
gets that far east the diurnal trend will be on the downswing.
Chambers

Thursday through Tuesday...

Overall pattern through the extended continues to look fairly
active. An upper ridge will get broken down on Thursday and Friday
before building back over the region next weekend.

Latest guidance indicates the ridge will break down in a couple
different waves. The first wave will slide across southern Canada
on Thursday, with an associated cold front dropping south through
the area late in the day into Thursday evening. This will bring
the return chances for some showers and thunderstorms. Depending
on the timing of the front, the gusty northwest winds associated
with it could be a fire weather concern. The second wave, in the
form of an upper trough, looks to eject out of the Pac NW and into
the Northern Rockies Thursday night bringing cooler temperatures
and chances for showers and thunderstorms on Friday. Friday looks
to have the highest chances for precipitation during the extended.

Upper ridging builds back into the region for Saturday and Sunday
bringing a return to hot and dry conditions. Another ridge
breakdown is possible late in the day on Monday as an area of low
pressure is progged to slide east across the Canadian border,
dropping a cold front through the area and bringing chances for
showers and thunderstorms Monday and possibly Tuesday.

High temperatures look to range from the 90s on Thursday, cooling
to the upper 70s to 80s on Friday. Highs in the 80s and 90s
return for the weekend, with another cooldown next week dropping
temperatures back into the 80s. Overnight lows look to be in the
50s and 60s for most nights. STP/Hooley

&&

.AVIATION...

VFR conditions will prevail for the next 24 hours outside of
thunderstorms. Isolated to scattered thunderstorms are expected
this evening into the early morning hours. The strongest activity
will be east of Billings and a few severe storms with large hail,
damaging winds and locally heavy rainfall are possible. In the
vicinity of thunderstorms expect local MVFR conditions, and
occasional mountain and pass obscuration. Chambers

&&

.PRELIMINARY POINT TEMP/POPS...

    Wed     Thu     Fri     Sat     Sun     Mon     Tue
-----------------------------------------------------------
BIL 061/097 065/095 063/082 060/090 062/097 065/092 061/090
    21/U    41/U    34/T    10/U    00/U    11/U    11/U
LVM 055/095 055/092 053/082 051/090 055/096 056/089 054/089
    22/T    32/T    33/T    10/U    00/U    11/U    11/U
HDN 058/100 062/098 060/084 056/090 057/099 062/095 059/092
    21/U    31/U    34/T    21/U    00/U    11/U    11/U
MLS 062/095 066/095 064/083 059/085 060/095 064/093 062/089
    31/U    41/U    35/T    31/U    00/U    11/U    11/U
4BQ 064/095 066/093 063/082 059/082 059/092 063/092 062/088
    31/U    31/U    35/T    32/T    00/U    01/U    11/U
BHK 056/090 059/094 059/082 056/082 055/089 058/092 059/088
    41/U    42/T    35/T    52/T    00/U    01/U    21/U
SHR 056/095 059/093 056/080 053/085 054/093 058/092 056/088
    31/U    31/U    24/T    21/U    00/U    11/U    11/U

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...Severe Thunderstorm Watch 339 in effect until 11 PM MDT this
      evening FOR ZONES 31-32-36-57-58-138-139-169-171.
WY...None.

&&

weather.gov/billings

In the hours before

Local storm report, Jul 6, 6:40 PM MDT, 2 hours 33 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BILLINGS MT
640 PM MDT TUE JUL 06 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0638 PM     HAIL             13 WSW HYSHAM           46.19N 107.44W
07/06/2021  E1.75 INCH       TREASURE           MT   TRAINED SPOTTER

&&

JKL

Special weather statement, Jul 6, 7:42 PM MDT, 1 hour 31 minutes before

Special Weather Statement
National Weather Service Billings MT
742 PM MDT Tue Jul 6 2021

MTZ138-WYZ199-070230-
Southern Big Horn MT-Sheridan Foothills WY-
742 PM MDT Tue Jul 6 2021

...SIGNIFICANT WEATHER ADVISORY...

At 741 PM MDT, Doppler radar was tracking a strong thunderstorm over
Lodge Grass, or 31 miles south of Hardin, moving southeast at 40 mph.

Dime size hail and wind gusts up to 50 mph are possible with this
storm.

Locations impacted include...
Ranchester, Lodge Grass, Wyola, Tongue River Reservoir, Rosebud
Battlefield Park and Parkman.

A Severe Thunderstorm Watch remains in effect until 1100 PM MDT for
south central and southeastern Montana.

LAT...LON 4528 10757 4541 10740 4519 10677 4518 10676
      4513 10661 4482 10715
TIME...MOT...LOC 0141Z 312DEG 34KT 4530 10741

Carrothers

Local storm report, Jul 6, 7:45 PM MDT, 1 hour 28 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BILLINGS MT
745 PM MDT TUE JUL 06 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0700 PM     HAIL             9 SSE HORN MT           46.04N 107.34W
07/06/2021  E1.75 INCH       TREASURE           MT   TRAINED SPOTTER

            WINDOWS BROKEN

0725 PM     HAIL             25 SSE HYSHAM           45.93N 107.05W
07/06/2021  E1.00 INCH       TREASURE           MT   PUBLIC

0735 PM     HAIL             23 ENE HARDIN           45.84N 107.16W
07/06/2021  E1.00 INCH       BIG HORN           MT   TRAINED SPOTTER

&&

JKL

Special weather statement, Jul 6, 8:38 PM MDT, 35 minutes before

Special Weather Statement
National Weather Service Billings MT
838 PM MDT Tue Jul 6 2021

MTZ138-WYZ198-199-070330-
Southern Big Horn MT-Northeast Bighorn Mountains WY-
Sheridan Foothills WY-
838 PM MDT Tue Jul 6 2021

...SIGNIFICANT WEATHER ADVISORY...

At 838 PM MDT, Doppler radar was tracking a strong thunderstorm 7
miles northwest of Ranchester, or 20 miles northwest of Sheridan,
moving southeast at 25 mph.

Nickel size hail and wind gusts up to 50 mph are possible with this
storm.

Locations impacted include...
Sheridan, Ranchester, Dayton, Big Horn, Parkman, Banner and Story.

A Severe Thunderstorm Watch remains in effect until 1100 PM MDT for
south central Montana.

LAT...LON 4501 10739 4513 10718 4473 10663 4456 10691
      4456 10700
TIME...MOT...LOC 0238Z 326DEG 24KT 4500 10724

Carrothers

Local storm report, Jul 6, 9:04 PM MDT, 9 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BILLINGS MT
904 PM MDT TUE JUL 06 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0835 PM     HAIL             10 ESE BUSBY            45.53N 106.77W
07/06/2021  E1.00 INCH       BIG HORN           MT   TRAINED SPOTTER

0900 PM     HAIL             17 SSE BIRNEY           45.19N 106.36W
07/06/2021  E1.00 INCH       ROSEBUD            MT   TRAINED SPOTTER

&&

VERTZ

Local storm report, Jul 6, 9:12 PM MDT, 1 minute before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BILLINGS MT
912 PM MDT TUE JUL 06 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0901 PM     HAIL             RANCHESTER              44.91N 107.17W
07/06/2021  E0.75 INCH       SHERIDAN           WY   TRAINED SPOTTER

0907 PM     HAIL             RANCHESTER              44.91N 107.16W
07/06/2021  E1.00 INCH       SHERIDAN           WY   TRAINED SPOTTER

            LOTS OF PEA-SIZE. SOME QUARTER-SIZE SCATTERED THROUGHOUT.

&&

VERTZ

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 6, 7:42 PM MDT	Special Weather Statement	BYZ	Sheridan	48 min
Jul 6, 8:38 PM MDT	Special Weather Statement	BYZ	Sheridan	52 min
Jul 6, 9:22 PM MDT	Severe Thunderstorm Warning	BYZ	Sheridan	38 min

Nearby

Severe Thunderstorm Warnings in Wyoming, 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.