Alert archive / Wyoming / Tornado Warnings in 2007

Tornado Warning 4, NWS Cheyenne, WY

May 20, 2007Laramie County, Wyoming

NWS Cheyenne, WY issued this tornado warning at May 20, 2007, 11:27 AM MDT for Laramie County, Wyoming. It was in force for 24 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
May 20, 2007, 11:27 AM MDT (17:27 UTC)
Expired
May 20, 2007, 11:51 AM MDT
In force
24 min
Issued by
NWS Cheyenne, WY
Area
Counties, with a storm outline in the text

County Laramie County, WY

The radar

The Cheyenne radar (KCYS), 0 km from the middle of the area, began a volume at 17:28 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

Denver, CO (KDNR), launched 12:00Z, 5.5 hours before the alert went out and 195 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, Denver, CO at 12:00Z on 2007-05-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Denver, CO at 12:00Z on 2007-05-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 0 square meters per square second.1939Sfc1 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
2 J/kg
Mixed-layer CIN
-394 J/kg
Mixed-layer LCL
1955 m above ground
0-6 km bulk shear
7 kt
0-1 km storm-relative helicity
0 m²/s²
0-3 km storm-relative helicity
-11 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000 
WFUS55 KCYS 201728
TORCYS
WYC021-201800-
/O.NEW.KCYS.TO.W.0004.070520T1727Z-070520T1800Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE CHEYENNE WY
1127 AM MDT SUN MAY 20 2007

THE NATIONAL WEATHER SERVICE IN CHEYENNE HAS ISSUED A

* TORNADO WARNING FOR...
  SOUTH CENTRAL LARAMIE COUNTY IN SOUTHEAST WYOMING...
  THIS INCLUDES THE CITY OF CHEYENNE...

* UNTIL NOON MDT

* AT 1119 AM MDT...LOCAL LAW ENFORCEMENT REPORTED A TORNADO NEAR
  CHEYENNE...MOVING EAST AT 10 MPH.

* THE TORNADO WILL BE NEAR...
  CHEYENNE BY 1145 AM MDT...
  NORTH CHEYENNE BY 1155 AM MDT...

MOVE INTO A BASEMENT OR AN INTERIOR ROOM ON THE LOWEST FLOOR OF A
STURDY BUILDING. ABANDON MOBILE HOMES AND VEHICLES.

REPORT SEVERE WEATHER TO THE NATIONAL WEATHER SERVICE OFFICE IN
CHEYENNE AT 1-800-269-6220.

LAT...LON 4121 10495 4103 10492 4104 10460 4127 10464

$$
SOWKO
2 follow-up statements
000 
WWUS55 KCYS 201737
SVSCYS

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHEYENNE WY
1134 AM MDT SUN MAY 20 2007

WYC021-201800-
/O.CON.KCYS.TO.W.0004.000000T0000Z-070520T1800Z/
LARAMIE WY-
1134 AM MDT SUN MAY 20 2007

...A TORNADO WARNING REMAINS IN EFFECT UNTIL NOON MDT FOR SOUTH
CENTRAL LARAMIE COUNTY...

AT 1128 AM MDT...LOCAL LAW ENFORCEMENT REPORTED A FUNNEL CLOUD AND
POSSIBLE SMALL TORNADO.  THIS POSSIBLE TORNADO WAS LOCATED NEAR 
CHEYENNE AND WAS MOVING SLOWLY EAST AT LESS THAN 10 MPH.

THE POSSIBLE TORNADO WILL BE NEAR...
  I-80 MM 370 BY NOON MDT...

REPORT SEVERE WEATHER TO THE NATIONAL WEATHER SERVICE OFFICE IN
CHEYENNE AT 1-800-269-6220.

LAT...LON 4121 10495 4103 10492 4104 10460 4127 10464

$$

SOWKO
000 
WWUS55 KCYS 201751
SVSCYS

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHEYENNE WY
1150 AM MDT SUN MAY 20 2007

WYC021-201800-
/O.CAN.KCYS.TO.W.0004.000000T0000Z-070520T1800Z/
LARAMIE WY-
1150 AM MDT SUN MAY 20 2007

...THE TORNADO WARNING FOR SOUTH CENTRAL LARAMIE COUNTY IS
CANCELLED...

LAW ENFORCEMENT AND NUMEROUS STORM SPOTTERS HAVE CONFIRMED THAT THE 
FUNNEL CLOUD HAS DISSIPATED...THUS THE WARNING HAS BEEN CANCELLED.  

LAT...LON 4121 10495 4103 10492 4104 10460 4127 10464

$$

SOWKO

The office that day

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

IssuedProductOfficeCountiesLasted
May 20, 1:36 PM MDTSevere Thunderstorm WarningCYSLaramie54 min
May 20, 2:28 PM MDTSevere Thunderstorm WarningCYSLaramie62 min

Nearby

Tornado Warnings in Wyoming, 2007Every tornado warning in 2007Tornadoes in 2007

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.