SPC MESOSCALE DISCUSSION 0660 FOR WRN OK AND NWRN TX
CONCERNING...TORNADO WATCH 198...

LATEST INSTABILITY AND SHEAR ANALYSES CONTINUE TO INDICATE A VERY
FAVORABLE ENVIRONMENT FOR SUPERCELLS AND POSSIBLE TORNADOES ACROSS
WRN OK...EAST OF WELL DEFINED DRY LINE NOW NEAR THE OK/TX PNHDL
BORDER. MEAN-MIXED CAPES HAVE INCREASED IN THE PAST HOUR WITH
VALUES FROM 1000-1500 J/KG ACROSS THE WW. IN ADDITION...BRN SHEAR
VALUES REMAIN IN THE 50-70 M2/S2 RANGE.

PRIMARY CONCERN CONTINUES TO CENTER AROUND THE POTENTIAL FOR
INTENSE CONVECTION. SMALL TCU/CBS HAVE BEEN TRYING TO DEVELOP OVER
THE PAST HOUR OR SO INVOF THE DRY LINE BUT HAVE YET TO INTENSIFY.
THIS MAY SIGNIFY SOME WEAKNESSES FOR DEEP CONVECTION IN THE
BOUNDARY LAYER OVER WRN OK. EXCEPTION IS WHERE CONVERGENCE IS
STRONGER OVER FAR NRN OK INTO SRN KS.

GIVEN THE STRONG COOLING AT MID LEVELS...STEEPNESS OF THE LAPSE
RATES AND STRENGTH OF SHEAR OVER THE REGION...SEVERE STORMS STILL
EXPECTED TO DEVELOP DURING THE NEXT FEW HOURS AS CONVERGENCE AXIS
SHIFTS EWD ACROSS WRN OK.

..EVANS.. 05/05/01