Alert archive / Colorado / Severe Thunderstorm Watches in 2002

Severe Thunderstorm Watch 421

June 12, 20028 counties in Colorado

The Storm Prediction Center issued this severe thunderstorm watch at Jun 12, 2002, 5:30 PM MDT for 8 counties in Colorado. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued: Jun 12, 2002, 5:30 PM MDT (23:30 UTC)
Expired: Jun 12, 2002, 11:00 PM MDT
In force: 6 hr
Issued by: the Storm Prediction Center

Counties Bent County, CO, Cheyenne County, CO, Crowley County, CO, Elbert County, CO, Kiowa County, CO, Lincoln County, CO, Otero County, CO, Prowers County, CO

The radar

The Pueblo radar (KPUX), 71 km from the middle of the area, began a volume at 23:33 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.

Warnings issued inside it

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

Issued	Product	Office	Counties	Lasted
Jun 12, 6:32 PM MDT	Severe Thunderstorm Warning	BOU	Lincoln	28 min
Jun 12, 6:56 PM MDT	Severe Thunderstorm Warning	GLD	Cheyenne	64 min

The nearest sounding before it

Denver, CO (KDNR), launched 12:00Z, 11.5 hours before the alert went out and 133 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1733 m above ground
0-6 km bulk shear: 41 kt
0-1 km storm-relative helicity: -32 m²/s²
0-3 km storm-relative helicity: 64 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000 
WWUS20 KWNS 122314
SEL1  
SPC WW 122309
COZ000-130500-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 421
STORM PREDICTION CENTER NORMAN OK
509 PM MDT WED JUN 12 2002

THE STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

EASTERN COLORADO                           

EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 530 PM UNTIL
1100 PM MDT.

HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE SEVERE THUNDERSTORM WATCH AREA IS ALONG AND 55 STATUTE MILES
NORTH AND SOUTH OF A LINE FROM 50 MILES SOUTHWEST OF LIMON COLORADO
TO 35 MILES EAST NORTHEAST OF LAMAR COLORADO.

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...

DISCUSSION...HIGH BASED STORMS ARE DEVELOPING OVER THE PALMER
DIVIDE AND FRONT RANGE...AND THESE STORMS SHOULD GRADUALLY
INTENSIFY AND MOVE E/SEWD THROUGH THE EVENING.  SBCAPE VALUES NEAR
1000 J/KG AND 0-6 KM SHEAR OF 40-50 KT WILL SUPPORT A FEW
SUPERCELLS WITH LARGE HAIL AND STRONG OUTFLOW WINDS.  BY EARLY
TONIGHT...STORMS MAY COALESCE INTO AN MCS AND MOVE SEWD TOWARD SW
KS LATER TONIGHT.

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 450.  MEAN STORM
MOTION VECTOR 30020.


...THOMPSON

393,1041 390,1020 372,1020 375,1041

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 11, 7:30 PM MDT	Severe Thunderstorm Watch	SPC	Cheyenne, Kiowa, Kit Carson, Lincoln, Washington, Yuma	6 hr

Nearby

Severe Thunderstorm Watches in Colorado, 2002 Every severe thunderstorm watch in 2002

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.