Alert archive / Wyoming / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 4, NWS Billings, MT

May 15, 2017Sheridan County, Wyoming

NWS Billings, MT issued this severe thunderstorm warning at May 15, 2017, 3:03 PM MDT for Sheridan County, Wyoming. It was in force for 39 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
May 15, 2017, 3:03 PM MDT (21:03 UTC)
Expired
May 15, 2017, 3:42 PM MDT
In force
39 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), 180 km from the middle of the area, began a volume at 21:06 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 nearest sounding before it

Riverton, WY (KRIW), launched 12:00Z, 9.1 hours before the alert went out and 227 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, Riverton, WY at 12:00Z on 2017-05-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Riverton, WY at 12:00Z on 2017-05-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -80 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1899 m above ground
0-6 km bulk shear
62 kt
0-1 km storm-relative helicity
-80 m²/s²
0-3 km storm-relative helicity
79 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

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 May 15, 10:12 AM MDT, 4 hours 51 minutes earlier.

Area forecast discussion, May 15, 10:12 AM MDT, 4 hours 51 minutes before
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Hazardous weather outlook, May 15, 5:00 AM MDT, 10 hours 3 minutes before
Hazardous Weather Outlook
National Weather Service Billings MT
500 AM MDT Mon May 15 2017

MTZ028>042-056>058-063>068-WYZ098-099-161100-
Southern Wheatland-Musselshell-Treasure-Northern Rosebud-Custer-
Fallon-Northern Stillwater-Yellowstone-Powder River-Carter-
Southern Big Horn-Eastern Carbon-Northern Park-
Northern Sweet Grass-Golden Valley-Red Lodge Foothills-
Northern Big Horn-Southern Rosebud-Judith Gap-Paradise Valley-
Livingston Area-Beartooth Foothills-Absaroka/Beartooth Mountains-
Crazy Mountains-Northeast Bighorn Mountains-Sheridan Foothills-
500 AM MDT Mon May 15 2017

This Hazardous Weather Outlook is for portions of central
Montana...south central Montana...southeast Montana and north
central Wyoming.

* Strong Thunderstorms are possible over southeast Montana this
  afternoon and evening with small hail and strong wind gusts.

* Rain Wednesday and Thursday: Periods of moderate to locally heavy
  rain are possible west of a Roundup to Broadus line, with 1 to 2
  inches of rainfall possible.

* Snow Wednesday and Thursday: Periods of heavy snow are expected
  mainly above 7000 feet, with accumulations over a foot possible.

* Potential Impacts: Rising water on rivers and streams, minor
  flooding of low lying areas, very muddy roads, general travel
  difficulties, possible power outages due to heavy wet snow, and
  dangerous wet and cold conditions for young livestock.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Hazardous Weather Outlook is issued when hazardous weather could
impact the region within the next week. Be sure to stay tuned for
future updates as locations, timing, and impacts could change.
Begin preparations to mitigate any impacts that could result from
the hazardous weather.

&&

In the hours before

Special weather statement, May 15, 2:48 PM MDT, 15 minutes before
Special Weather Statement
National Weather Service Billings MT
248 PM MDT MON MAY 15 2017

WYZ099-152130-
Sheridan Foothills WY-
248 PM MDT MON MAY 15 2017

...SIGNIFICANT WEATHER ADVISORY...

At 247 PM MDT, Doppler radar was tracking a strong thunderstorm 11
miles northeast of Lake De Smet, or 17 miles north of Buffalo, moving
northeast at 15 mph.

Dime size hail, wind gusts up to 50 mph and torrential rainfall are
possible with this storm. Very heavy rain will cause a dramatic
reduction in visibility, along with ponding of water on area
roadways.

Locations impacted include...
Clearmont, Leiter and Ucross.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is also occurring with this storm, and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

&&

LAT...LON 4462 10672 4492 10642 4456 10608 4456 10666
TIME...MOT...LOC 2047Z 235DEG 12KT 4458 10659

TWH

The office that day

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

IssuedProductOfficeCountiesLasted
May 15, 3:24 PM MDTWinter Storm WatchBYZCarbon, Park, Stillwater, Sweet Grass, Wheatland36 hr
May 15, 3:47 PM MDTSpecial Weather StatementBYZ13 min
May 15, 4:55 PM MDTSpecial Weather StatementBYZPowder River50 min
May 15, 5:30 PM MDTSpecial Weather StatementBYZCuster45 min
May 15, 2:48 PM MDTSpecial Weather StatementBYZSheridan42 min

Nearby

Severe Thunderstorm Warnings in Wyoming, 2017Every severe thunderstorm warning in 2017

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.