Alert archive / Colorado / Severe Thunderstorm Watches in 2011

Severe Thunderstorm Watch 641

July 13, 201113 counties in Colorado

The Storm Prediction Center issued this severe thunderstorm watch at Jul 13, 2011, 5:13 PM MDT for 13 counties in Colorado. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
Jul 13, 2011, 5:13 PM MDT (23:13 UTC)
Expired
Jul 13, 2011, 11:00 PM MDT
In force
6 hr
Issued by
the Storm Prediction Center
Largest hail expected
2 in
Strongest gust expected
60 kt

Counties Adams County, CO, Arapahoe County, CO, Boulder County, CO, Broomfield County, CO, Clear Creek County, CO, Denver County, CO, Douglas County, CO, El Paso County, CO, Gilpin County, CO, Jefferson County, CO, Larimer County, CO, Pueblo County, CO, Weld County, CO

The radar

The Denver radar (KFTG), 43 km from the middle of the area, began a volume at 23:13 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 SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes
20%
One or more EF2 to EF5 tornadoes
5%
Ten or more severe wind reports
30%
One or more gusts of 65 knots or more
30%
Ten or more severe hail reports
30%
One or more hailstones of 2 inches or more
20%
Six or more combined severe hail and wind reports
70%

Warnings issued inside it

20 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
Jul 13, 5:56 PM MDTSevere Thunderstorm WarningBOUAdams, Arapahoe, Denver, Douglas, Jefferson49 min
Jul 13, 6:08 PM MDTSevere Thunderstorm WarningPUBFremont, Pueblo26 min
Jul 13, 6:14 PM MDTSevere Thunderstorm WarningPUBEl Paso61 min
Jul 13, 6:16 PM MDTSevere Thunderstorm WarningPUBPueblo34 min
Jul 13, 6:17 PM MDTFlash Flood WarningBOUBoulder3 hr
Jul 13, 6:40 PM MDTSevere Thunderstorm WarningBOUAdams, Arapahoe, Denver, Jefferson19 min
Jul 13, 6:50 PM MDTSevere Thunderstorm WarningPUBEl Paso55 min
Jul 13, 7:00 PM MDTSevere Thunderstorm WarningPUBEl Paso60 min
Jul 13, 7:13 PM MDTSevere Thunderstorm WarningBOUBoulder, Larimer34 min
Jul 13, 7:30 PM MDTSevere Thunderstorm WarningPUBPueblo45 min
Jul 13, 7:34 PM MDTSevere Thunderstorm WarningBOULarimer26 min
Jul 13, 7:38 PM MDTSevere Thunderstorm WarningPUBEl Paso67 min
Jul 13, 7:59 PM MDTSevere Thunderstorm WarningBOULarimer, Weld28 min
Jul 13, 8:08 PM MDTFlash Flood WarningBOUBoulder103 min
Jul 13, 8:09 PM MDTSevere Thunderstorm WarningPUBHuerfano, Las Animas, Pueblo22 min
Jul 13, 9:01 PM MDTSevere Thunderstorm WarningBOUDouglas, Jefferson44 min
Jul 13, 9:05 PM MDTSevere Thunderstorm WarningBOUAdams, Arapahoe, Denver55 min
Jul 13, 9:55 PM MDTSevere Thunderstorm WarningBOUAdams, Weld33 min
Jul 13, 10:30 PM MDTSevere Thunderstorm WarningPUBEl Paso32 min
Jul 13, 10:35 PM MDTFlash Flood WarningPUBEl Paso3 hr

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Denver, CO (KDNR), launched 12:00Z, 11.2 hours before the alert went out and 151 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 12:00Z on 2011-07-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 217 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Denver, CO at 12:00Z on 2011-07-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 26 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
217 J/kg
Mixed-layer CIN
-63 J/kg
Mixed-layer LCL
616 m above ground
0-6 km bulk shear
27 kt
0-1 km storm-relative helicity
26 m²/s²
0-3 km storm-relative helicity
73 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 13, 1:47 PM MDTMesoscale DiscussionSPCMesa, Moffat, Rio Blanco88 min
Jul 13, 2:23 PM MDTMesoscale DiscussionSPCAdams, Arapahoe, Broomfield, Cheyenne, Crowley, Denver and 9 more2 hr
Jul 13, 3:41 PM MDTTornado WatchSPCCheyenne, Elbert, Kit Carson, Lincoln6 hr

Nearby

Severe Thunderstorm Watches in Colorado, 2011Every severe thunderstorm watch 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.