Alert archive / Colorado / Tornado Warnings in 2011

Tornado Warning 2, NWS Denver/Boulder, CO

May 17, 2011Washington County, Colorado

NWS Denver/Boulder, CO issued this tornado warning at May 17, 2011, 5:57 PM MDT for Washington County, Colorado. It was in force for 33 min. 6 reports 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 17, 2011, 5:57 PM MDT (23:57 UTC)
Expired: May 17, 2011, 6:30 PM MDT
In force: 33 min
Issued by: NWS Denver/Boulder, CO
Area: Storm-based polygon

County Washington County, CO

The radar

The Denver radar (KFTG), 114 km from the middle of the area, began a volume at 23:55 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

Time	Report	Where	Remark
May 17, 5:57 PM MDT	TORNADO	4 Nw Thurman, CO	STORM MOVING NORTHEAST AT 25 MPH
May 17, 6:08 PM MDT	TORNADO	2 Nw Thurman, CO	ON THE GROUND FOR APPROXIMATELY 2 MILES. ALSO SEVERAL ADDITIONAL FUNNEL CLOUDS OBSERVED
May 17, 6:18 PM MDT	HAIL 1	4 S Anton, CO	QUARTER TO PENNY SIZE HAIL PLUS HEAVY RAIN.
May 17, 6:18 PM MDT	TORNADO	4 S Anton, CO	TRAFFIC STOPPED INCLUDING SCHOOL BUSES DUE TO HEAVY RAIN AND HAIL
May 17, 6:34 PM MDT	HAIL 0.88	3 E Anton, CO
May 17, 6:35 PM MDT	HAIL 0.88	3 E Anton, CO

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

The nearest sounding before it

Denver, CO (KDNR), launched 12:00Z, 12.0 hours before the alert went out and 19 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1149 m above ground
0-6 km bulk shear: 48 kt
0-1 km storm-relative helicity: 142 m²/s²
0-3 km storm-relative helicity: 160 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.

394 
WFUS55 KBOU 172357
TORBOU
COC121-180030-
/O.NEW.KBOU.TO.W.0002.110517T2357Z-110518T0030Z/

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

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A

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

* UNTIL 630 PM MDT

* AT 557 PM MDT...TRAINED WEATHER SPOTTERS REPORTED A TORNADO 4 MILES
  NORTHWEST OF THURMAN...OR 35 MILES NORTHEAST OF LIMON. THIS STORM
  WAS MOVING NORTHEAST AT 25 MPH.

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO THURMAN AND
  ANTON.

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 3981 10322 3972 10305 3956 10326 3960 10332
TIME...MOT...LOC 2357Z 207DEG 22KT 3965 10324

$$

2 follow-up statements

366 
WWUS55 KBOU 180020
SVSBOU

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

COC121-180030-
/O.CON.KBOU.TO.W.0002.000000T0000Z-110518T0030Z/
WASHINGTON CO-
620 PM MDT TUE MAY 17 2011

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 630 PM MDT FOR SOUTH
CENTRAL WASHINGTON COUNTY...

AT 620 PM MDT...THE PUBLIC REPORTED A TORNADO.  THIS TORNADO WAS 
LOCATED 4 MILES SOUTH OF ANTON...OR 31 MILES SOUTH OF AKRON. THIS 
STORM WAS MOVING NORTH AT 20 MPH.

LOCATIONS REMAINING IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
ANTON.

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 3961 10321 3962 10326 3981 10322 3972 10305
TIME...MOT...LOC 0020Z 189DEG 18KT 3974 10321

$$

161 
WWUS55 KBOU 180027
SVSBOU

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

COC121-180037-
/O.EXP.KBOU.TO.W.0002.000000T0000Z-110518T0030Z/
WASHINGTON CO-
627 PM MDT TUE MAY 17 2011

...THE TORNADO WARNING FOR SOUTH CENTRAL WASHINGTON COUNTY WILL
EXPIRE AT 630 PM MDT...

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 3961 10321 3962 10326 3981 10322 3972 10305
TIME...MOT...LOC 0027Z 189DEG 18KT 3977 10320

$$

The office that day

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

Issued	Product	Office	Counties	Lasted
May 17, 4:20 PM MDT	Severe Thunderstorm Warning	BOU	Adams, Morgan	40 min
May 17, 5:20 PM MDT	Tornado Warning	BOU	Morgan	24 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.