Alert archive / Wyoming / Severe Thunderstorm Warnings in 2013

Severe Thunderstorm Warning 216, NWS Cheyenne, WY

August 3, 2013Laramie County, Wyoming

NWS Cheyenne, WY issued this severe thunderstorm warning at Aug 3, 2013, 3:30 PM MDT for Laramie County, Wyoming. It was in force for 45 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: Aug 3, 2013, 3:30 PM MDT (21:30 UTC)
Expired: Aug 3, 2013, 4:15 PM MDT
In force: 45 min
Issued by: NWS Cheyenne, WY
Area: Storm-based polygon
Hail: 1.75 in
Wind: 70.0 mph

County Laramie County, WY

The radar

The Cheyenne radar (KCYS), 20 km from the middle of the area, began a volume at 21:32 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.

Issued	Product	Office	Lasted
Aug 3, 2:35 PM MDT	Tornado Watch	SPC	6 hr

The nearest sounding before it

Denver, CO (KDEN), launched 12:00Z, 9.5 hours before the alert went out and 202 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: 46 J/kg
Mixed-layer CIN: -295 J/kg
Mixed-layer LCL: 2189 m above ground
0-6 km bulk shear: 15 kt
0-1 km storm-relative helicity: 32 m²/s²
0-3 km storm-relative helicity: 43 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 Cheyenne, WY wrote its last area forecast discussion before this severe thunderstorm warning went out at Aug 3, 3:20 PM MDT, 10 minutes earlier.

Area forecast discussion, Aug 3, 3:20 PM MDT, 10 minutes before

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Hazardous weather outlook, Aug 3, 2:49 PM MDT, 41 minutes before

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In the hours before

Special weather statement, Aug 3, 2:15 PM MDT, 1 hour 15 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHEYENNE WY
215 PM MDT SAT AUG 3 2013

WYZ116-117-032100-
SOUTH LARAMIE RANGE WY-SOUTH LARAMIE RANGE FOOTHILLS WY-
215 PM MDT SAT AUG 3 2013

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHWESTERN LARAMIE AND
SOUTHEASTERN ALBANY COUNTIES UNTIL 300 PM MDT...

AT 213 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A
STRONG THUNDERSTORM 6 MILES NORTHEAST OF VIRGINIA DALE...OR 26 MILES
SOUTHWEST OF CHEYENNE...MOVING NORTHEAST AT 15 MPH.

HAIL UP TO ONE-HALF INCH IN DIAMETER AND WIND GUSTS UP TO 40 MPH ARE
EXPECTED WITH THIS STORM...ALONG WITH HEAVY RAIN.

LOCATIONS NEAR THE PATH OF THIS STORM INCLUDE...
  CRYSTAL LAKE CAMPGROUND...
  CRYSTAL LAKE RESERVOIR...

THIS INCLUDES INTERSTATE 80 IN WYOMING BETWEEN MILE MARKERS 333 AND
350.

THIS STORM MAY INTENSIFY...SO BE CERTAIN TO MONITOR LOCAL RADIO AND
TV STATIONS...AS WELL AS LOCAL CABLE TV OUTLETS... FOR ADDITIONAL
INFORMATION AND POSSIBLE WARNINGS FROM THE NATIONAL WEATHER SERVICE.

TORRENTIAL RAIN...WHICH MAY FLOOD LOW LYING AREAS SUCH AS DITCHES AND
UNDERPASSES...IS ALSO LIKELY. DO NOT DRIVE YOUR VEHICLE ON A FLOODED
ROADWAY.

&&

LAT...LON 4116 10535 4116 10499 4099 10508 4099 10536
      4099 10537
TIME...MOT...LOC 2015Z 200DEG 11KT 4100 10524

HAMMER

Local storm report, Aug 3, 2:47 PM MDT, 43 minutes before

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Local storm report, Aug 3, 3:12 PM MDT, 18 minutes before

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Local storm report, Aug 3, 3:14 PM MDT, 16 minutes before

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Local storm report, Aug 3, 3:25 PM MDT, 5 minutes before

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The office that day

Everything else NWS Cheyenne, WY issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 3, 2:15 PM MDT	Special Weather Statement	CYS	Laramie	45 min
Aug 3, 2:29 PM MDT	Severe Thunderstorm Warning	CYS	Laramie	46 min
Aug 3, 3:02 PM MDT	Severe Thunderstorm Warning	CYS	Laramie	43 min
Aug 3, 4:00 PM MDT	Special Weather Statement	CYS	Albany	60 min
Aug 3, 4:12 PM MDT	Severe Thunderstorm Warning	CYS	Goshen, Laramie, Platte	48 min
Aug 3, 4:38 PM MDT	Special Weather Statement	CYS	Albany	67 min
Aug 3, 4:50 PM MDT	Special Weather Statement	CYS		55 min
Aug 3, 4:52 PM MDT	Special Weather Statement	CYS	Platte	38 min
Aug 3, 4:58 PM MDT	Areal Flood Advisory	CYS	Albany, Laramie	3 hr
Aug 3, 5:07 PM MDT	Severe Thunderstorm Warning	CYS	Albany, Converse	68 min
Aug 3, 5:20 PM MDT	Special Weather Statement	CYS	Platte	40 min
Aug 3, 5:22 PM MDT	Flash Flood Warning	CYS	Albany, Converse	3 hr

Nearby

Severe Thunderstorm Warnings in Wyoming, 2013 Every severe thunderstorm warning in 2013

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.