Alert archive / Colorado / Tornado Watches in 2010

Tornado Watch 368

June 21, 20104 counties in Colorado

The Storm Prediction Center issued this tornado watch at Jun 21, 2010, 2:53 PM MDT for 4 counties in Colorado. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued
Jun 21, 2010, 2:53 PM MDT (20:53 UTC)
Expired
Jun 21, 2010, 7:46 PM MDT
In force
5 hr
Issued by
the Storm Prediction Center
Largest hail expected
2.5 in
Strongest gust expected
60 kt

Counties Logan County, CO, Morgan County, CO, Washington County, CO, Weld County, CO

The radar

The Denver radar (KFTG), 80 km from the middle of the area, began a volume at 20:53 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
30%
One or more EF2 to EF5 tornadoes
20%
Ten or more severe wind reports
30%
One or more gusts of 65 knots or more
20%
Ten or more severe hail reports
50%
One or more hailstones of 2 inches or more
40%
Six or more combined severe hail and wind reports
70%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Jun 21, 2:53 PM MDTSevere Thunderstorm WarningBOUAdams, Boulder, Broomfield, Weld52 min
Jun 21, 3:36 PM MDTSevere Thunderstorm WarningBOUAdams, Broomfield, Weld39 min
Jun 21, 4:17 PM MDTSevere Thunderstorm WarningBOUAdams, Morgan, Weld43 min
Jun 21, 4:59 PM MDTTornado WarningBOUMorgan46 min
Jun 21, 5:28 PM MDTTornado WarningBOULogan, Morgan, Washington47 min
Jun 21, 6:00 PM MDTTornado WarningBOUWashington30 min
Jun 21, 6:26 PM MDTTornado WarningBOUWashington34 min
Jun 21, 6:50 PM MDTSevere Thunderstorm WarningBOULogan, Phillips, Sedgwick30 min

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, 8.9 hours before the alert went out and 94 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 2010-06-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2927 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 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 2010-06-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -20 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
2927 J/kg
Mixed-layer CIN
-4 J/kg
Mixed-layer LCL
561 m above ground
0-6 km bulk shear
29 kt
0-1 km storm-relative helicity
-20 m²/s²
0-3 km storm-relative helicity
40 m²/s²
Significant tornado parameter
-0.2
Supercell composite
-1.2

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jun 20, 9:18 PM MDTMesoscale DiscussionSPCLogan, Phillips, Sedgwick, Yuma87 min
Jun 20, 10:43 PM MDTSevere Thunderstorm WatchSPCYuma6 hr
Jun 21, 12:02 AM MDTSevere Thunderstorm WatchSPCLogan, Morgan, Phillips, Sedgwick, Washington2 hr
Jun 21, 2:31 PM MDTMesoscale DiscussionSPCAdams, Arapahoe, Boulder, Broomfield, Denver, Douglas and 6 more89 min
Jun 21, 5:03 PM MDTMesoscale DiscussionSPCKit Carson, Logan, Morgan, Phillips, Sedgwick, Washington and 1 more87 min
Jun 21, 5:56 PM MDTSevere Thunderstorm WatchSPCKit Carson, Yuma4 hr
Jun 21, 5:58 PM MDTMesoscale DiscussionSPCBaca, Prowers92 min

Nearby

Tornado Watches in Colorado, 2010Every tornado watch in 2010

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.