Alert archive / Colorado / Tornado Warnings in 2012

Tornado Warning 1, NWS Denver/Boulder, CO

April 11, 2012Adams County, Arapahoe County, Denver County, Colorado

NWS Denver/Boulder, CO issued this tornado warning at Apr 11, 2012, 5:06 PM MDT for Adams County, Arapahoe County, Denver County, Colorado. 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
Apr 11, 2012, 5:06 PM MDT (23:06 UTC)
Expired
Apr 11, 2012, 5:30 PM MDT
In force
24 min
Issued by
NWS Denver/Boulder, CO
Area
Storm-based polygon

Counties Adams County, CO, Arapahoe County, CO, Denver County, CO

The radar

The Denver radar (KFTG), 22 km from the middle of the area, began a volume at 23:06 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

Denver, CO (KDNR), launched 12:00Z, 11.1 hours before the alert went out and 133 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 2012-04-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 9 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 2012-04-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 44 square meters per square second.193958Sfc1 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
9 J/kg
Mixed-layer CIN
-468 J/kg
Mixed-layer LCL
724 m above ground
0-6 km bulk shear
19 kt
0-1 km storm-relative helicity
44 m²/s²
0-3 km storm-relative helicity
48 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.

701 
WFUS55 KBOU 112306
TORBOU
COC001-005-031-112330-
/O.NEW.KBOU.TO.W.0001.120411T2306Z-120411T2330Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE DENVER CO
506 PM MDT WED APR 11 2012

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A

* TORNADO WARNING FOR...
  NORTHWESTERN ARAPAHOE COUNTY IN NORTHEAST COLORADO
  WESTERN ADAMS COUNTY IN NORTHEAST COLORADO
  EASTERN DENVER COUNTY IN NORTHEAST COLORADO

* UNTIL 530 PM MDT

* AT 505 PM MDT...THE PUBLIC REPORTED A TORNADO NEAR 38TH AND TOWER  
  ROAD...ABOUT 6 MILES NORTH OF AURORA...OR 10 MILES NORTHEAST OF    
  DENVER. THIS STORM WAS MOVING NORTH AT 25 MPH.

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO BUCKLEY
  AFB...BARR LAKE...WESTERN DENVER INTERNATIONAL AIRPORT...
  NORTHEASTERN DENVER...NORTHEASTERN COMMERCE CITY AND NORTHWESTERN
  AURORA.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW. MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF A
STURDY BUILDING. AVOID WINDOWS. IF IN A MOBILE HOME...A VEHICLE OR
OUTDOORS...MOVE TO THE CLOSEST SUBSTANTIAL SHELTER AND PROTECT
YOURSELF FROM FLYING DEBRIS.

IN ADDITION TO THE TORNADO...THIS STORM IS CAPABLE OF PRODUCING LARGE
DAMAGING HAIL AND DESTRUCTIVE STRAIGHT LINE WINDS.

&&

LAT...LON 3996 10481 3996 10465 3967 10474 3968 10493
TIME...MOT...LOC 2305Z 199DEG 18KT 3982 10479

$$
1 follow-up statement
179 
WWUS55 KBOU 112327
SVSBOU

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
527 PM MDT WED APR 11 2012

COC001-005-031-112337-
/O.EXP.KBOU.TO.W.0001.000000T0000Z-120411T2330Z/
ARAPAHOE CO-ADAMS CO-DENVER CO-
527 PM MDT WED APR 11 2012

...THE TORNADO WARNING FOR EASTERN DENVER...WESTERN ADAMS AND
NORTHWESTERN ARAPAHOE COUNTIES WILL EXPIRE AT 530 PM MDT...

THE THUNDERSTORM THAT PROMPTED THE WARNING HAS WEAKENED THEREFORE 
THE TORNADO WARNING WILL BE ALLOWED TO EXPIRE.

LAT...LON 3996 10481 3996 10465 3967 10474 3968 10493
TIME...MOT...LOC 2327Z 199DEG 18KT 3992 10474

$$

The office that day

Everything else NWS Denver/Boulder, CO issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 11, 4:44 PM MDTSevere Thunderstorm WarningBOUAdams, Arapahoe, Denver27 min
Apr 11, 4:56 PM MDTSevere Thunderstorm WarningBOUAdams, Denver32 min

Nearby

Tornado Warnings in Colorado, 2012Every tornado warning in 2012Tornadoes in 2012

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.