Alert archive / Colorado / Tornado Warnings in 2011

Tornado Warning 4, NWS Denver/Boulder, CO

May 17, 2011Washington County, Colorado

NWS Denver/Boulder, CO issued this tornado warning at May 17, 2011, 6:13 PM MDT for Washington County, Colorado. It was in force for 15 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 17, 2011, 6:13 PM MDT (00:13 UTC)
Expired: May 17, 2011, 6:28 PM MDT
In force: 15 min
Issued by: NWS Denver/Boulder, CO
Area: Storm-based polygon

County Washington County, CO

The radar

The Denver radar (KFTG), 108 km from the middle of the area, began a volume at 00:14 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 00:00Z, 0.2 hours before the alert went out and 6 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: 26 J/kg
Mixed-layer CIN: -104 J/kg
Mixed-layer LCL: 1293 m above ground
0-6 km bulk shear: 41 kt
0-1 km storm-relative helicity: 22 m²/s²
0-3 km storm-relative helicity: 146 m²/s²
Significant tornado parameter: -0.0
Supercell composite: -1.5

Open this sounding in Storm Lab

The text

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

936 
WFUS55 KBOU 180013
TORBOU
COC121-180100-
/O.NEW.KBOU.TO.W.0004.110518T0013Z-110518T0100Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE DENVER CO
613 PM MDT TUE MAY 17 2011

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A

* TORNADO WARNING FOR...
  CENTRAL WASHINGTON COUNTY IN NORTHEAST COLORADO

* UNTIL 700 PM MDT

* AT 613 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO OVER SOUTH
  CENTRAL WASHINGTON COUNTY...OR 29 MILES SOUTH OF AKRON. THIS STORM
  WAS MOVING NORTH AT 10 MPH.

* THE SEVERE THUNDERSTORM WILL REMAIN OVER MAINLY RURAL AREAS OF THE
  WARNED COUNTY.

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.

&&

LAT...LON 3991 10336 3991 10317 3973 10325 3974 10330
TIME...MOT...LOC 0013Z 183DEG 8KT 3975 10326

$$

1 follow-up statement

108 
WWUS55 KBOU 180028
SVSBOU

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
628 PM MDT TUE MAY 17 2011

COC121-180038-
/O.CAN.KBOU.TO.W.0004.000000T0000Z-110518T0100Z/
WASHINGTON CO-
628 PM MDT TUE MAY 17 2011

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

THE THUNDERSTORM THAT PROMPTED THE WARNING HAS EXITED THE AREA. A 
TORNADO WARNING REMAINS IN EFFECT FOR CENTRAL WASHINGTON COUNTY 
UNTIL 7 PM.

LAT...LON 3991 10336 3991 10317 3973 10325 3974 10330
TIME...MOT...LOC 0028Z 183DEG 8KT 3978 10326

$$

The office that day

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

Issued	Product	Office	Counties	Lasted
May 17, 6:11 PM MDT	Tornado Warning	BOU	Washington	34 min
May 17, 6:26 PM MDT	Tornado Warning	BOU	Washington	34 min
May 17, 6:32 PM MDT	Severe Thunderstorm Warning	BOU	Logan, Washington	43 min
May 17, 6:59 PM MDT	Tornado Warning	BOU	Washington	31 min
May 18, 4:10 AM MDT	Flash Flood Watch	BOU	Boulder, Larimer	16 hr
May 18, 4:43 AM MDT	Winter Storm Warning	BOU	Boulder, Grand, Jackson, Larimer	24 hr
May 18, 4:43 AM MDT	Winter Weather Advisory	BOU	Boulder, Clear Creek, Douglas, Gilpin, Grand, Jackson and 4 more	24 hr
May 18, 1:13 PM MDT	Tornado Warning	BOU	Adams, Broomfield	31 min
May 18, 2:16 PM MDT	Areal Flood Advisory	BOU	Adams, Broomfield	119 min
May 18, 2:29 PM MDT	Tornado Warning	BOU	Adams	14 min
May 18, 2:38 PM MDT	Severe Thunderstorm Warning	BOU	Adams, Broomfield, Weld	19 min
May 18, 5:47 PM MDT	Severe Thunderstorm Warning	BOU	Lincoln	58 min

Nearby

Tornado Warnings in Colorado, 2011 Every tornado warning in 2011 Tornadoes in 2011

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.