Alert archive / Colorado / Severe Thunderstorm Watches in 2016

Severe Thunderstorm Watch 421

July 28, 201610 counties in Colorado

The Storm Prediction Center issued this severe thunderstorm watch at Jul 28, 2016, 7:33 PM MDT for 10 counties in Colorado. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued
Jul 28, 2016, 7:33 PM MDT (01:33 UTC)
Expired
Jul 29, 2016, 12:00 AM MDT
In force
4 hr
Issued by
the Storm Prediction Center
Largest hail expected
2 in
Strongest gust expected
60 kt

Counties Baca County, CO, Bent County, CO, Cheyenne County, CO, Crowley County, CO, El Paso County, CO, Kiowa County, CO, Las Animas County, CO, Otero County, CO, Prowers County, CO, Pueblo County, CO

The radar

The Pueblo radar (KPUX), 82 km from the middle of the area, began a volume at 01:37 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
5%
One or more EF2 to EF5 tornadoes
5%
Ten or more severe wind reports
30%
One or more gusts of 65 knots or more
20%
Ten or more severe hail reports
30%
One or more hailstones of 2 inches or more
30%
Six or more combined severe hail and wind reports
40%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Jul 28, 7:45 PM MDTSevere Thunderstorm WarningPUBCrowley, Kiowa25 min
Jul 28, 8:28 PM MDTSevere Thunderstorm WarningGLDCheyenne27 min
Jul 28, 8:42 PM MDTSevere Thunderstorm WarningGLDCheyenne33 min
Jul 28, 9:01 PM MDTSevere Thunderstorm WarningPUBEl Paso, Pueblo44 min
Jul 28, 9:08 PM MDTSevere Thunderstorm WarningPUBEl Paso52 min
Jul 28, 9:25 PM MDTFlash Flood WarningPUBEl Paso, Pueblo3 hr
Jul 28, 9:31 PM MDTSevere Thunderstorm WarningPUBEl Paso29 min
Jul 28, 9:34 PM MDTSevere Thunderstorm WarningGLDCheyenne, Kit Carson26 min
Jul 28, 9:40 PM MDTSevere Thunderstorm WarningPUBEl Paso50 min
Jul 28, 9:59 PM MDTSevere Thunderstorm WarningPUBEl Paso46 min
Jul 28, 10:05 PM MDTFlash Flood WarningPUBEl Paso3 hr
Jul 28, 10:09 PM MDTSevere Thunderstorm WarningPUBEl Paso51 min
Jul 28, 10:53 PM MDTSevere Thunderstorm WarningPUBEl Paso28 min
Jul 28, 10:59 PM MDTSevere Thunderstorm WarningPUBEl Paso46 min
Jul 28, 11:43 PM MDTSevere Thunderstorm WarningPUBEl Paso19 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 (KDEN), launched 00:00Z, 1.6 hours before the alert went out and 204 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 2016-07-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1611 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 00:00Z on 2016-07-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 28 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
1611 J/kg
Mixed-layer CIN
-61 J/kg
Mixed-layer LCL
1861 m above ground
0-6 km bulk shear
43 kt
0-1 km storm-relative helicity
28 m²/s²
0-3 km storm-relative helicity
261 m²/s²
Significant tornado parameter
0.2
Supercell composite
8.4

Open this sounding in Storm Lab

The text

As transmitted.

976 
WWUS20 KWNS 290130
SEL1  
SPC WW 290130
COZ000-290600-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 421
NWS STORM PREDICTION CENTER NORMAN OK
730 PM MDT THU JUL 28 2016

THE NWS STORM PREDICTION CENTER HAS ISSUED A

* SEVERE THUNDERSTORM WATCH FOR PORTIONS OF 
  SOUTHEASTERN COLORADO

* EFFECTIVE THIS THURSDAY NIGHT FROM 730 PM UNTIL MIDNIGHT MDT.

* PRIMARY THREATS INCLUDE...
  ISOLATED VERY LARGE HAIL EVENTS TO 2 INCHES IN DIAMETER POSSIBLE
  ISOLATED DAMAGING WIND GUSTS TO 70 MPH POSSIBLE

SUMMARY...INCREASING COVERAGE OF THUNDERSTORMS IS NOTED OVER PARTS
OF SOUTHEASTERN COLORADO...IN AN ENVIRONMENT SOMEWHAT FAVORABLE FOR
CONTINUING GROWTH/INTENSIFICATION AS ACTIVITY MOVES GENERALLY
SOUTHEASTWARD THROUGH THE EVENING.

THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 55
STATUTE MILES EITHER SIDE OF A LINE FROM 45 MILES NORTH NORTHWEST
OF LA JUNTA COLORADO TO 15 MILES NORTHEAST OF SPRINGFIELD
COLORADO.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU1).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY
DO PRODUCE TORNADOES.

&&

OTHER WATCH INFORMATION...CONTINUE...WW 418...WW 419...WW 420...

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 550. MEAN STORM
MOTION VECTOR 30025.


...EDWARDS

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 28, 7:01 PM MDTMesoscale DiscussionSPCBaca, Bent, Cheyenne, Crowley, El Paso, Kiowa and 5 more59 min
Jul 28, 10:39 PM MDTMesoscale DiscussionSPCBaca, Bent, Cheyenne, Crowley, Elbert, El Paso and 7 more2 hr
Jul 29, 12:34 PM MDTMesoscale DiscussionSPCAdams, Arapahoe, Boulder, Broomfield, Clear Creek, Denver and 7 more116 min
Jul 29, 1:08 PM MDTSevere Thunderstorm WatchSPCAdams, Arapahoe, Boulder, Broomfield, Denver, Douglas and 11 more9 hr
Jul 29, 2:42 PM MDTMesoscale DiscussionSPCHuerfano, Las Animas, Otero, Pueblo2 hr
Jul 29, 5:27 PM MDTMesoscale DiscussionSPCAdams, Arapahoe, Boulder, Broomfield, Denver, Douglas and 13 more108 min

Nearby

Severe Thunderstorm Watches in Colorado, 2016Every severe thunderstorm watch in 2016

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.