Alert archive / Colorado / Tornado Warnings in 2014

Tornado Warning 20, NWS Denver/Boulder, CO

May 21, 2014Adams County, Arapahoe County, Denver County, Colorado

NWS Denver/Boulder, CO issued this tornado warning at May 21, 2014, 3:18 PM MDT for Adams County, Arapahoe County, Denver County, Colorado. It was in force for 27 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
May 21, 2014, 3:18 PM MDT (21:18 UTC)
Expired
May 21, 2014, 3:45 PM MDT
In force
27 min
Issued by
NWS Denver/Boulder, CO
Area
Storm-based polygon
Tornado
Observed
Hail
1.5 in

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

The radar

The Denver radar (KFTG), 4 km from the middle of the area, began a volume at 21:19 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

TimeReportWhereRemark
May 21, 3:39 PM MDTHAIL 1.755 N Bennett, CO

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

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
May 21, 12:34 PM MDTTornado WatchSPC8 hr

The nearest sounding before it

Denver, CO (KDEN), launched 12:00Z, 9.3 hours before the alert went out and 110 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 2014-05-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 268 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 2014-05-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 86 square meters per square second.19395878Sfc1 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
268 J/kg
Mixed-layer CIN
-75 J/kg
Mixed-layer LCL
786 m above ground
0-6 km bulk shear
36 kt
0-1 km storm-relative helicity
86 m²/s²
0-3 km storm-relative helicity
158 m²/s²
Significant tornado parameter
0.1
Supercell composite
2.3

Open this sounding in Storm Lab

The text

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

711 
WFUS55 KBOU 212118
TORBOU
COC001-005-031-212145-
/O.NEW.KBOU.TO.W.0020.140521T2118Z-140521T2145Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE DENVER CO
318 PM MDT WED MAY 21 2014

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A

* TORNADO WARNING FOR...
  NORTH CENTRAL ARAPAHOE COUNTY IN NORTHEAST COLORADO...
  EAST CENTRAL DENVER COUNTY IN NORTHEAST COLORADO...
  SOUTH CENTRAL ADAMS COUNTY IN NORTHEAST COLORADO...

* UNTIL 345 PM MDT

* AT 314 PM MDT...A CONFIRMED TORNADO WAS LOCATED OVER NORTHEASTERN 
  AURORA...OR 24 MILES EAST OF DENVER...MOVING EAST AT 20 MPH.  
  TRAINED WEATHER SPOTTERS CHASING THE STORM CONTINUE TO REPORT 
  FUNNEL CLOUDS AND WALL CLOUDS ASSOCIATED WITH THIS THUNDERSTORM.  
  THE STORM IS ALSO PRODUCING HEAVY RAIFALL...MAKING VISUAL 
  CONFIRMATION OF ANY TORNADOES DIFFICULT.  THE STORM HAS A HISTORY 
  OF PRODUCING A TORNADO...AND IS CAPABLE OF PRODUCING ADDITIONAL 
  TORNADIC ACTIVITY WITH LITTLE WARNING. 

  HAZARD...DAMAGING TORNADO AND PING PONG BALL SIZE HAIL. 

  SOURCE...WEATHER SPOTTERS CONFIRMED TORNADO. 

  IMPACT...FLYING DEBRIS WILL BE DANGEROUS TO THOSE CAUGHT WITHOUT 
           SHELTER. MOBILE HOMES WILL BE DAMAGED OR DESTROYED. 
           DAMAGE TO ROOFS...WINDOWS AND VEHICLES WILL OCCUR.  TREE 
           DAMAGE IS LIKELY. 

* LOCATIONS IMPACTED INCLUDE...
  EASTERN AURORA...EASTERN DENVER INTERNATIONAL AIRPORT...BENNETT...
  STRASBURG...MANILA VILLAGE AND WATKINS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TO REPEAT...A TORNADO IS ON THE GROUND. TAKE COVER NOW! MOVE TO A
BASEMENT OR 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.

MOTORISTS SHOULD NOT TAKE SHELTER UNDER HIGHWAY OVERPASSES. IF YOU
CANNOT SAFELY DRIVE AWAY FROM THE TORNADO...AS A LAST RESORT...EITHER
PARK YOUR VEHICLE AND STAY PUT...OR ABANDON YOUR VEHICLE AND LIE DOWN
IN A LOW LYING AREA AND PROTECT YOURSELF FROM FLYING DEBRIS.

HEAVY RAINFALL MAY HIDE THIS TORNADO. DO NOT WAIT TO SEE OR HEAR THE
TORNADO. TAKE COVER NOW.

&&

LAT...LON 3968 10469 3990 10464 3992 10425 3965 10426
TIME...MOT...LOC 2114Z 268DEG 18KT 3977 10450 

TORNADO...OBSERVED
HAIL...1.50IN

$$

DANKERS

The office that day

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

IssuedProductOfficeCountiesLasted
May 20, 6:19 PM MDTSevere Thunderstorm WarningBOUAdams, Arapahoe, Elbert, Lincoln, Washington41 min
May 20, 10:51 PM MDTSpecial Weather StatementBOUWeld39 min
May 20, 11:43 PM MDTSpecial Weather StatementBOUWeld62 min
May 20, 11:51 PM MDTAreal Flood AdvisoryBOUMorgan, Weld114 min
May 21, 6:47 AM MDTAreal Flood AdvisoryBOUMorgan3 hr
May 21, 1:00 PM MDTSevere Thunderstorm WarningBOUJefferson45 min
May 21, 1:36 PM MDTSevere Thunderstorm WarningBOUAdams, Arapahoe, Denver39 min
May 21, 1:56 PM MDTTornado WarningBOUAdams, Arapahoe, Denver34 min
May 21, 2:21 PM MDTSevere Thunderstorm WarningBOUAdams, Denver39 min
May 21, 2:23 PM MDTTornado WarningBOUAdams, Arapahoe, Denver22 min
May 21, 2:42 PM MDTTornado WarningBOUAdams, Arapahoe33 min
May 21, 3:47 PM MDTSevere Thunderstorm WarningBOUAdams, Arapahoe28 min
May 21, 3:57 PM MDTSevere Thunderstorm WarningBOUDouglas, Elbert48 min
May 21, 4:18 PM MDTSevere Thunderstorm WarningBOUAdams, Arapahoe42 min
May 21, 4:57 PM MDTTornado WarningBOUAdams48 min
May 21, 5:34 PM MDTSevere Thunderstorm WarningBOUAdams, Morgan, Washington41 min

Nearby

Tornado Warnings in Colorado, 2014Every tornado warning in 2014Tornadoes in 2014

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.