Alert archive / Colorado / Severe Thunderstorm Warnings in 2011

Severe Thunderstorm Warning 3, NWS Denver/Boulder, CO

May 17, 2011Logan County, Washington County, Colorado

NWS Denver/Boulder, CO issued this severe thunderstorm warning at May 17, 2011, 6:32 PM MDT for Logan County, Washington County, Colorado. It was in force for 43 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, 6:32 PM MDT (00:32 UTC)
Expired
May 17, 2011, 7:15 PM MDT
In force
43 min
Issued by
NWS Denver/Boulder, CO
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties Logan County, CO, Washington County, CO

The radar

The Denver radar (KFTG), 135 km from the middle of the area, began a volume at 00:33 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, 0.5 hours before the alert went out and 80 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-pSkew-T log-p diagram, Denver, CO at 00:00Z on 2011-05-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 26 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Denver, CO at 00:00Z on 2011-05-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 22 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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.

691 
WUUS55 KBOU 180032
SVRBOU
COC075-121-180115-
/O.NEW.KBOU.SV.W.0003.110518T0032Z-110518T0115Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE DENVER CO
632 PM MDT TUE MAY 17 2011

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTH CENTRAL WASHINGTON COUNTY IN NORTHEAST COLORADO
  SOUTHWESTERN LOGAN COUNTY IN NORTHEAST COLORADO

* UNTIL 715 PM MDT

* AT 628 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING DAMAGING WINDS UP TO ABOUT
  60 MPH. THESE WINDS WERE SPREADING NORTHEAST ACROSS EXTREME  
  NORTHWEST WASHINGTON AND SOUTHWEST LOGAN COUNTIES. 

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO WILLARD...
  PREWITT RESERVOIR...PAWNEE PASS...MERINO...LOGAN CORNERS...ATWOOD
  AND STERLING.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IF YOU ARE CAUGHT OUTSIDE...SEEK SHELTER FROM THE WEATHER IN A STRONG
BUILDING. DAMAGING WIND...LARGE HAIL...VERY HEAVY RAIN...AND DEADLY
LIGHTNING ARE ALL POSSIBLE IN SEVERE THUNDERSTORMS. STAY INSIDE AWAY
FROM WINDOWS UNTIL THE STORM HAS PASSED.

&&

LAT...LON 4072 10322 4045 10302 4036 10332 4052 10345
      4053 10358 4076 10358
TIME...MOT...LOC 0028Z 212DEG 23KT 4053 10337
WIND...HAIL 60MPH <.75IN

$$


BAKER
2 follow-up statements
912 
WWUS55 KBOU 180058
SVSBOU

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

COC075-121-180115-
/O.CON.KBOU.SV.W.0003.000000T0000Z-110518T0115Z/
WASHINGTON CO-LOGAN CO-
658 PM MDT TUE MAY 17 2011

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 715 PM MDT
FOR SOUTHWESTERN LOGAN AND NORTH CENTRAL WASHINGTON COUNTIES...

AT 654 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO 
INDICATE POTENTIALLY DAMAGING THUNDERSTORM WINDS UP TO ABOUT 60 MPH 
SPREADING NORTHEAST ACROSS SOUTHWEST LOGAN COUNTY. 

LOCATIONS REMAINING IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
WILLARD...PREWITT RESERVOIR...PAWNEE PASS...MERINO...LOGAN CORNERS...
ATWOOD AND STERLING.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IF YOU ARE CAUGHT OUTSIDE...SEEK SHELTER FROM THE WEATHER IN A STRONG
BUILDING. DAMAGING WIND...LARGE HAIL...VERY HEAVY RAIN...AND DEADLY
LIGHTNING ARE ALL POSSIBLE IN SEVERE THUNDERSTORMS. STAY INSIDE AWAY
FROM WINDOWS UNTIL THE STORM HAS PASSED.

&&

LAT...LON 4072 10322 4045 10302 4036 10332 4052 10345
      4053 10358 4076 10358
TIME...MOT...LOC 0054Z 212DEG 23KT 4067 10325
WIND...HAIL 60MPH <.75IN

$$


BAKER
276 
WWUS55 KBOU 180113
SVSBOU

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

COC075-121-180122-
/O.EXP.KBOU.SV.W.0003.000000T0000Z-110518T0115Z/
WASHINGTON CO-LOGAN CO-
713 PM MDT TUE MAY 17 2011

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHWESTERN LOGAN AND NORTH
CENTRAL WASHINGTON COUNTIES WILL EXPIRE AT 715 PM MDT...

THE THUNDERSTORM WINDS THAT PROMPTED THE WARNING HAVE WEAKENED AND 
ARE NO LONGER EXPECTED TO PRODUCE DAMAGE.

LAT...LON 4072 10322 4045 10302 4036 10332 4052 10345
      4053 10358 4076 10358
TIME...MOT...LOC 0112Z 212DEG 23KT 4077 10317

$$


BAKER

The office that day

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

IssuedProductOfficeCountiesLasted
May 17, 6:11 PM MDTTornado WarningBOUWashington34 min
May 17, 6:13 PM MDTTornado WarningBOUWashington15 min
May 17, 6:26 PM MDTTornado WarningBOUWashington34 min
May 17, 6:59 PM MDTTornado WarningBOUWashington31 min
May 18, 4:10 AM MDTFlash Flood WatchBOUBoulder, Larimer16 hr
May 18, 4:43 AM MDTWinter Storm WarningBOUBoulder, Grand, Jackson, Larimer24 hr
May 18, 4:43 AM MDTWinter Weather AdvisoryBOUBoulder, Clear Creek, Douglas, Gilpin, Grand, Jackson and 4 more24 hr
May 18, 1:13 PM MDTTornado WarningBOUAdams, Broomfield31 min
May 18, 2:16 PM MDTAreal Flood AdvisoryBOUAdams, Broomfield119 min
May 18, 2:29 PM MDTTornado WarningBOUAdams14 min
May 18, 2:38 PM MDTSevere Thunderstorm WarningBOUAdams, Broomfield, Weld19 min
May 18, 5:47 PM MDTSevere Thunderstorm WarningBOULincoln58 min

Nearby

Severe Thunderstorm Warnings in Colorado, 2011Every severe thunderstorm warning 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.