

000 

WWUS20 KWNS 192154

SEL3

SPC WW 192154

KSZ000-OKZ000-200500-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 423

NWS STORM PREDICTION CENTER NORMAN OK

455 PM CDT TUE JUN 19 2007



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       SOUTHWEST KANSAS

       EAST CENTRAL INTO MUCH OF CENTRAL AND NORTHWEST OKLAHOMA



EFFECTIVE THIS TUESDAY AFTERNOON FROM 455 PM UNTIL MIDNIGHT CDT.



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 APPROXIMATELY ALONG AND 100

STATUTE MILES EAST AND WEST OF A LINE FROM 55 MILES NORTHEAST OF

LIBERAL KANSAS TO 65 MILES SOUTH SOUTHEAST OF CHANDLER OKLAHOMA.

FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH

OUTLINE UPDATE (WOUS64 KWNS WOU3).



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 417...WW 418...WW

419...WW 420...WW 421...WW 422...



DISCUSSION...SCATTERED THUNDERSTORMS ARE FORMING ON THE RESIDUAL

BAROCLINIC ZONE ACROSS NRN OK/SRN OK...WHILE A SEPARATE CLUSTER IS

BACK-BUILDING WWD ALONG THIS BOUNDARY INTO E CENTRAL OK.  VERTICAL

SHEAR IS MARGINAL FOR SUPERCELLS NEAR THE KS/OK BORDER...AND EVEN

WEAKER TO THE S TOWARD I-40.  STILL...EXTREME INSTABILITY /MLCAPE

VALUES NEAR 6000 J/KG/ IS PRESENT ALONG AND S OF THE BOUNDARY...WITH

MEAN BOUNDARY LAYER DEWPOINTS IN THE UPPER 70S BENEATH STEEP MID

LEVEL LAPSE RATES.  ANY SUPERCELL STRUCTURES WILL ENHANCE THE LARGE

HAIL THREAT...WHILE CELL MERGERS COULD EVENTUALLY RESULT IN UPSCALE

GROWTH INTO AN MCS WITH DAMAGING WIND POTENTIAL.



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 600. MEAN STORM

MOTION VECTOR 35015.





...THOMPSON

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