Alert archive / Oklahoma / Severe Thunderstorm Watches in 2002

Severe Thunderstorm Watch 83

April 11, 200217 counties in Oklahoma

The Storm Prediction Center issued this severe thunderstorm watch at Apr 11, 2002, 2:30 PM CDT for 17 counties in Oklahoma. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
Apr 11, 2002, 2:30 PM CDT (19:30 UTC)
Expired
Apr 11, 2002, 8:00 PM CDT
In force
6 hr
Issued by
the Storm Prediction Center

Counties Alfalfa County, OK, Blaine County, OK, Caddo County, OK, Canadian County, OK, Comanche County, OK, Custer County, OK, Dewey County, OK, Garfield County, OK, Grant County, OK, Greer County, OK, Jackson County, OK, Kay County, OK, Kingfisher County, OK, Kiowa County, OK, Major County, OK, Washita County, OK, Woods County, OK

The radar

The Altus AFB radar (KFDR), 133 km from the middle of the area, began a volume at 19:28 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

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

IssuedProductOfficeCountiesLasted
Apr 11, 5:53 PM CDTSevere Thunderstorm WarningOUNKay37 min
Apr 11, 6:29 PM CDTSevere Thunderstorm WarningOUNKay46 min
Apr 11, 7:15 PM CDTSevere Thunderstorm WarningOUNKay45 min

The nearest sounding before it

Fort Sill, OK (KFSI), launched 12:00Z, 7.5 hours before the alert went out and 105 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, Fort Sill, OK at 12:00Z on 2002-04-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Fort Sill, OK at 12:00Z on 2002-04-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 104 square meters per square second.1939Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1054 m above ground
0-6 km bulk shear
21 kt
0-1 km storm-relative helicity
104 m²/s²
0-3 km storm-relative helicity
120 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 111910
SEL3  
SPC WW 111905
OKZ000-120100-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 83
STORM PREDICTION CENTER NORMAN OK
205 PM CDT THU APR 11 2002

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

WESTERN AND NORTHWESTERN OKLAHOMA                           

EFFECTIVE THIS THURSDAY AFTERNOON AND EVENING FROM 230 PM UNTIL 800
PM CDT.

HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 60
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE SEVERE THUNDERSTORM WATCH AREA IS ALONG AND 50 STATUTE MILES
EAST AND WEST OF A LINE FROM 15 MILES EAST SOUTHEAST OF ALTUS
OKLAHOMA TO 45 MILES NORTH OF ENID OKLAHOMA.

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.


DISCUSSION...THUNDERSTORMS ARE EXPECTED TO DEVELOP ACROSS N
CENTRAL/NW OK IN THE NEXT 1-2 HOURS...WITH ADDITIONAL DEVELOPMENT
SWWD ACROSS WRN OK THIS AFTERNOON ALONG A SURFACE TROUGH.  MODERATE
INSTABILITY AND INCREASING MID LEVEL WINDS WILL SUPPORT A FEW
SEVERE STORMS... INCLUDING SUPERCELLS...WITH LARGE HAIL AND
ISOLATED DAMAGING WINDS THROUGH THIS EVENING.


AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2 INCHES.  EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 50
KNOTS.  A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500.  MEAN STORM
MOTION VECTOR 27020.


...THOMPSON

370,0970 343,0980 343,0995 370,0984

Nearby

Severe Thunderstorm Watches in Oklahoma, 2002Every 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.