Alert archive / Colorado / Tornado Warnings in 2011

Tornado Warning 8, NWS Denver/Boulder, CO

May 18, 2011Adams County, Colorado

NWS Denver/Boulder, CO issued this tornado warning at May 18, 2011, 2:29 PM MDT for Adams County, Colorado. It was in force for 14 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 18, 2011, 2:29 PM MDT (20:29 UTC)
Expired: May 18, 2011, 2:43 PM MDT
In force: 14 min
Issued by: NWS Denver/Boulder, CO
Area: Storm-based polygon

County Adams County, CO

The radar

The Denver radar (KFTG), 27 km from the middle of the area, began a volume at 20:31 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 18, 2:30 PM MDT	HAIL 1	Commerce City, 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, 8.5 hours before the alert went out and 139 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: 19 J/kg
Mixed-layer CIN: -37 J/kg
Mixed-layer LCL: 625 m above ground
0-6 km bulk shear: 46 kt
0-1 km storm-relative helicity: 3 m²/s²
0-3 km storm-relative helicity: 99 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.

047 
WFUS55 KBOU 182029
TORBOU
COC001-182100-
/O.NEW.KBOU.TO.W.0008.110518T2029Z-110518T2100Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE DENVER CO
229 PM MDT WED MAY 18 2011

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A

* TORNADO WARNING FOR...
  WEST CENTRAL ADAMS COUNTY IN NORTHEAST COLORADO

* UNTIL 300 PM MDT

* AT 228 PM MDT...WEATHER SERVICE DOPPLER RADAR INDICATED A          
  POSSIBLE TORNADO NEAR COMMERCE CITY...OR 8 MILES NORTHEAST OF      
  DENVER. THIS STORM WAS MOVING NORTHEAST AT 15 MPH.

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO BARR
  LAKE...EASTERN THORNTON AND COMMERCE CITY.

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 3996 10469 3980 10487 3981 10487 3981 10488
      3980 10489 3979 10491 3979 10490 3978 10493
      3996 10493
TIME...MOT...LOC 2028Z 203DEG 12KT 3983 10489

$$


BAKER

1 follow-up statement

980 
WWUS55 KBOU 182043
SVSBOU

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
243 PM MDT WED MAY 18 2011

COC001-182052-
/O.CAN.KBOU.TO.W.0008.000000T0000Z-110518T2100Z/
ADAMS CO-
243 PM MDT WED MAY 18 2011

...THE TORNADO WARNING FOR WEST CENTRAL ADAMS COUNTY IS CANCELLED...

THE THUNDERSTORM THAT PROMPTED THE WARNING HAS WEAKENED AND IS NO 
LONGER INDICATING A POSSIBLE TORNADO. HOWEVER THIS STORM CONTINUES 
TO PRODUCE HAIL AND HEAVY RAINFALL.

LAT...LON 3996 10469 3980 10487 3981 10487 3981 10488
      3980 10489 3979 10491 3979 10490 3978 10493
      3996 10493
TIME...MOT...LOC 2042Z 203DEG 12KT 3987 10487

$$


BAKER

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, 6:13 PM MDT	Tornado Warning	BOU	Washington	15 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, 2:38 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.