Alert archive / Colorado / Tornado Warnings in 2011
Tornado Warning 34, NWS Denver/Boulder, CO
NWS Denver/Boulder, CO issued this tornado warning at Aug 9, 2011, 2:45 PM MDT for Logan County, Colorado. It was in force for 45 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
- Aug 9, 2011, 2:45 PM MDT (20:45 UTC)
- Expired
- Aug 9, 2011, 3:30 PM MDT
- In force
- 45 min
- Issued by
- NWS Denver/Boulder, CO
- Area
- Storm-based polygon
County Logan County, CO
The radar
The Cheyenne radar (KCYS), 175 km from the middle of the area, began a volume at 20:45 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 |
|---|---|---|---|
| Aug 9, 2:58 PM MDT | HAIL 2 | 9 Nne Crook, CO | WIND GUST MEASURED AT 70 MPH. SNAPPED 3 INCH DIAMETER TREES DOWN. WEST WINDOWS CRACKED. |
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 |
|---|---|---|---|
| Aug 9, 1:51 PM MDT | Tornado Watch | SPC | 7 hr |
The nearest sounding before it
Denver, CO (KDNR), launched 12:00Z, 8.8 hours before the alert went out and 123 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.
- Mixed-layer CAPE
- 245 J/kg
- Mixed-layer CIN
- -295 J/kg
- Mixed-layer LCL
- 1813 m above ground
- 0-6 km bulk shear
- 55 kt
- 0-1 km storm-relative helicity
- 82 m²/s²
- 0-3 km storm-relative helicity
- 91 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
596
WFUS55 KBOU 092045
TORBOU
COC075-092130-
/O.NEW.KBOU.TO.W.0034.110809T2045Z-110809T2130Z/
BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE DENVER CO
245 PM MDT TUE AUG 9 2011
THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A
* TORNADO WARNING FOR...
NORTHEASTERN LOGAN COUNTY IN NORTHEAST COLORADO
* UNTIL 330 PM MDT
* AT 245 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO 9 MILES
NORTHWEST OF TWIN BUTTES...OR 30 MILES NORTHEAST OF STERLING. THIS
STORM WAS MOVING SOUTHEAST AT 15 MPH.
* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO TWIN BUTTES
AND CROOK.
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 4083 10265 4082 10289 4100 10293 4100 10271
4100 10266
TIME...MOT...LOC 2045Z 332DEG 14KT 4098 10289
$$2 follow-up statements
980
WWUS55 KBOU 092104
SVSBOU
SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
304 PM MDT TUE AUG 9 2011
COC075-092130-
/O.CON.KBOU.TO.W.0034.000000T0000Z-110809T2130Z/
LOGAN CO-
304 PM MDT TUE AUG 9 2011
...A TORNADO WARNING REMAINS IN EFFECT UNTIL 330 PM MDT FOR
NORTHEASTERN LOGAN COUNTY...
AT 302 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO. THIS STORM WAS
LOCATED 3 MILES NORTHWEST OF TWIN BUTTES...OR 29 MILES WEST OF
JULESBURG. THIS STORM WAS MOVING SOUTHEAST AT 15 MPH.
AT 258 PM MDT...A TRAINED SPOTTER LOCATED 9 MILES NORTH NORTHEAST OF
CROOK REPORTED HAIL UP TO 2 INCHES IN DIAMETER AND WIND GUSTS TO 70
MPH. SOME WINDOWS WERE CRACKED AND TREES DAMAGED.
LOCATIONS REMAINING IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
TWIN BUTTES AND CROOK.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
TAKE COVER NOW. MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF A
STURDY BUILDING. AVOID WINDOWS. IF IN A MOBILE HOME...A VEHICLE OR
OUTDOORS...MOVE TO THE CLOSEST SUBSTANTIAL SHELTER AND PROTECT
YOURSELF FROM FLYING DEBRIS.
A TORNADO WATCH REMAINS IN EFFECT UNTIL 900 PM MDT TUESDAY EVENING
FOR NORTHEAST COLORADO.
&&
LAT...LON 4083 10265 4082 10289 4100 10293 4100 10271
4100 10266
TIME...MOT...LOC 2102Z 328DEG 14KT 4093 10280
$$346
WWUS55 KBOU 092127
SVSBOU
SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
327 PM MDT TUE AUG 9 2011
COC075-092138-
/O.EXP.KBOU.TO.W.0034.000000T0000Z-110809T2130Z/
LOGAN CO-
327 PM MDT TUE AUG 9 2011
...THE TORNADO WARNING FOR NORTHEASTERN LOGAN COUNTY WILL EXPIRE AT
330 PM MDT...
THE THUNDERSTORM THAT PROMPTED THE WARNING HAS EXITED THE AREA.
A TORNADO WATCH REMAINS IN EFFECT UNTIL 900 PM MDT TUESDAY EVENING
FOR NORTHEAST COLORADO.
LAT...LON 4083 10265 4082 10289 4100 10293 4100 10271
4100 10266
TIME...MOT...LOC 2128Z 328DEG 14KT 4084 10273
$$The office that day
Everything else NWS Denver/Boulder, CO issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 8, 6:31 PM MDT | Severe Thunderstorm Warning | BOU | Logan, Phillips, Sedgwick | 43 min |
| Aug 9, 2:31 PM MDT | Severe Thunderstorm Warning | BOU | Logan | 44 min |
| Aug 9, 2:51 PM MDT | Severe Thunderstorm Warning | BOU | Phillips, Sedgwick | 39 min |
| Aug 9, 3:31 PM MDT | Severe Thunderstorm Warning | BOU | Phillips, Sedgwick | 27 min |
Nearby
Tornado Warnings in Colorado, 2011Every tornado warning in 2011Tornadoes 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.