Alert archive / Colorado / Tornado Warnings in 2011

Tornado Warning 27, NWS Denver/Boulder, CO

July 6, 2011Logan County, Weld County, Colorado

NWS Denver/Boulder, CO issued this tornado warning at Jul 6, 2011, 4:33 PM MDT for Logan County, Weld County, Colorado. It was in force for 42 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: Jul 6, 2011, 4:33 PM MDT (22:33 UTC)
Expired: Jul 6, 2011, 5:15 PM MDT
In force: 42 min
Issued by: NWS Denver/Boulder, CO
Area: Storm-based polygon

Counties Logan County, CO, Weld County, CO

The radar

The Cheyenne radar (KCYS), 107 km from the middle of the area, began a volume at 22:36 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
Jul 6, 4:53 PM MDT	TSTM WND GST 59	12 N Stoneham, CO	SUSTAINED 35-45 WITH GUSTS 50 TO 59 MPH. RW+ BUT NO HAIL.

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.

Issued	Product	Office	Lasted
Jul 6, 2:56 PM MDT	Severe Thunderstorm Watch	SPC	8 hr

The nearest sounding before it

Denver, CO (KDNR), launched 12:00Z, 10.6 hours before the alert went out and 101 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: 161 J/kg
Mixed-layer CIN: -159 J/kg
Mixed-layer LCL: 1212 m above ground
0-6 km bulk shear: 21 kt
0-1 km storm-relative helicity: -17 m²/s²
0-3 km storm-relative helicity: 90 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.

030 
WFUS55 KBOU 062233
TORBOU
COC075-123-062315-
/O.NEW.KBOU.TO.W.0027.110706T2233Z-110706T2315Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE DENVER CO
433 PM MDT WED JUL 6 2011

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A

* TORNADO WARNING FOR...
  WEST CENTRAL LOGAN COUNTY IN NORTHEAST COLORADO
  EAST CENTRAL WELD COUNTY IN NORTHEAST COLORADO

* UNTIL 515 PM MDT

* AT 433 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO 16 MILES
  NORTHWEST OF STONEHAM...OR 35 MILES WEST OF STERLING. THIS STORM
  WAS MOVING SOUTHEAST AT 25 MPH.

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO STONEHAM 
AND NEW RAYMER. 

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 4080 10345 4053 10357 4056 10375 4069 10392
      4092 10388
TIME...MOT...LOC 2233Z 308DEG 23KT 4081 10382

$$

1 follow-up statement

021 
WWUS55 KBOU 062313
SVSBOU

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
513 PM MDT WED JUL 6 2011

COC075-123-062322-
/O.EXP.KBOU.TO.W.0027.000000T0000Z-110706T2315Z/
LOGAN CO-WELD CO-
513 PM MDT WED JUL 6 2011

...THE TORNADO WARNING FOR EAST CENTRAL WELD AND WEST CENTRAL LOGAN
COUNTIES WILL EXPIRE AT 515 PM MDT...

THE THUNDERSTORM THAT PROMPTED THE WARNING HAS EXITED THE AREA.  A 
SEVERE THUNDERSTORM WARNING HAS REPLACED THE TORNADO WARNING. 

LAT...LON 4080 10345 4053 10357 4056 10375 4069 10392
      4092 10388
TIME...MOT...LOC 2312Z 308DEG 23KT 4066 10356

$$

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 5, 6:02 PM MDT	Special Weather Statement	BOU	Morgan	28 min
Jul 5, 7:12 PM MDT	Special Weather Statement	BOU	Logan, Washington	33 min
Jul 5, 7:29 PM MDT	Areal Flood Advisory	BOU	Morgan	91 min
Jul 5, 7:47 PM MDT	Severe Thunderstorm Warning	BOU	Logan, Washington	43 min
Jul 5, 8:33 PM MDT	Special Weather Statement	BOU	Phillips	27 min
Jul 5, 11:07 PM MDT	Areal Flood Advisory	BOU	Grand	36 hr
Jul 6, 3:48 AM MDT	Flash Flood Watch	BOU	Boulder, Larimer	15 hr
Jul 6, 2:00 PM MDT	Special Weather Statement	BOU	Douglas	30 min
Jul 6, 2:58 PM MDT	Severe Thunderstorm Warning	BOU	Elbert	48 min
Jul 6, 3:28 PM MDT	Severe Thunderstorm Warning	BOU	Arapahoe, Elbert	47 min
Jul 6, 4:02 PM MDT	Special Weather Statement	BOU	Weld	28 min
Jul 6, 5:00 PM MDT	Severe Thunderstorm Warning	BOU	Washington	33 min
Jul 6, 5:06 PM MDT	Severe Thunderstorm Warning	BOU	Adams, Logan, Morgan, Washington, Weld	39 min
Jul 6, 5:26 PM MDT	Severe Thunderstorm Warning	BOU	Adams, Denver, Weld	49 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.