Alert archive / Colorado / Severe Thunderstorm Watches in 2011

Severe Thunderstorm Watch 576

June 30, 201116 counties in Colorado; 9 counties in Utah

The Storm Prediction Center issued this severe thunderstorm watch at Jun 30, 2011, 9:06 AM MDT for 16 counties in Colorado; 9 counties in Utah. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued
Jun 30, 2011, 9:06 AM MDT (15:06 UTC)
Expired
Jun 30, 2011, 4:20 PM MDT
In force
7 hr
Issued by
the Storm Prediction Center
Largest hail expected
1.5 in
Strongest gust expected
65 kt
All 25 counties

Delta County, CO, Dolores County, CO, Eagle County, CO, Garfield County, CO, Gunnison County, CO, La Plata County, CO, Mesa County, CO, Moffat County, CO, Montezuma County, CO, Montrose County, CO, Ouray County, CO, Pitkin County, CO, Rio Blanco County, CO, Routt County, CO, San Juan County, CO, San Miguel County, CO, Carbon County, UT, Daggett County, UT, Duchesne County, UT, Emery County, UT, Grand County, UT, San Juan County, UT, Uintah County, UT, Wasatch County, UT, Wayne County, UT

The radar

The Grand Junction radar (KGJX), 139 km from the middle of the area, began a volume at 15:09 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
50%
One or more gusts of 65 knots or more
40%
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
80%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Jun 30, 9:15 AM MDTFlash Flood WarningSLCEmery3 hr
Jun 30, 9:22 AM MDTSevere Thunderstorm WarningSLCCarbon, Emery23 min
Jun 30, 9:26 AM MDTSevere Thunderstorm WarningSLCEmery34 min
Jun 30, 9:33 AM MDTSevere Thunderstorm WarningSLCEmery27 min
Jun 30, 9:46 AM MDTSevere Thunderstorm WarningSLCEmery29 min
Jun 30, 9:53 AM MDTSevere Thunderstorm WarningSLCCarbon, Emery52 min
Jun 30, 10:45 AM MDTSevere Thunderstorm WarningGJTGrand, Uintah45 min
Jun 30, 10:45 AM MDTSevere Thunderstorm WarningSLCCarbon, Duchesne19 min
Jun 30, 11:28 AM MDTSevere Thunderstorm WarningGJTMoffat, Rio Blanco62 min
Jun 30, 12:18 PM MDTSevere Thunderstorm WarningGJTMoffat, Rio Blanco42 min
Jun 30, 12:28 PM MDTSevere Thunderstorm WarningGJTMoffat, Rio Blanco47 min
Jun 30, 12:41 PM MDTSevere Thunderstorm WarningGJTGarfield, Rio Blanco49 min
Jun 30, 12:55 PM MDTSevere Thunderstorm WarningGJTMoffat50 min
Jun 30, 2:28 PM MDTSevere Thunderstorm WarningGJTMesa36 min
Jun 30, 2:38 PM MDTSevere Thunderstorm WarningGJTEagle, Pitkin52 min
Jun 30, 3:24 PM MDTSevere Thunderstorm WarningGJTEagle, Routt51 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

Grand Junction, CO (KGJT), launched 12:00Z, 3.1 hours before the alert went out and 119 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, Grand Junction, CO at 12:00Z on 2011-06-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 28 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, Grand Junction, CO at 12:00Z on 2011-06-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 279 square meters per square second.19395878Sfc1 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
28 J/kg
Mixed-layer CIN
-222 J/kg
Mixed-layer LCL
2557 m above ground
0-6 km bulk shear
59 kt
0-1 km storm-relative helicity
279 m²/s²
0-3 km storm-relative helicity
248 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jun 30, 8:51 AM MDTMesoscale DiscussionSPCDelta, Dolores, Eagle, Garfield, Gunnison, Hinsdale and 10 more54 min
Jun 30, 11:57 AM MDTMesoscale DiscussionSPCAdams, Boulder, Broomfield, Chaffee, Clear Creek, Denver and 14 more63 min
Jun 30, 12:18 PM MDTSevere Thunderstorm WatchSPCAdams, Arapahoe, Boulder, Broomfield, Chaffee, Clear Creek and 17 more9 hr
Jun 30, 1:49 PM MDTMesoscale DiscussionSPCAdams, Arapahoe, Boulder, Broomfield, Clear Creek, Delta and 25 more116 min
Jun 30, 4:17 PM MDTMesoscale DiscussionSPCAdams, Arapahoe, Boulder, Broomfield, Chaffee, Clear Creek and 25 more118 min

Nearby

Severe Thunderstorm Watches in Colorado, 2011Severe Thunderstorm Watches in Utah, 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.