MESOSCALE DISCUSSION 0649
   NWS STORM PREDICTION CENTER NORMAN OK
   1141 PM CDT THU APR 30 2009
   
   AREAS AFFECTED...OK
   
   CONCERNING...SEVERE THUNDERSTORM WATCH 218...
   
   VALID 010441Z - 010545Z
   
   THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 218
   CONTINUES.
   
   AN ISOLATED SEVERE THREAT SHOULD CONTINUE ACROSS THE ERN PART OF WW
   218 AND MAY AFFECT AREAS EAST OF THE WATCH LATER TONIGHT. LARGE HAIL
   AND ISOLATED WIND DAMAGE WOULD LIKELY BE THE PRIMARY THREATS. A NEW
   WW MAY BE NEEDED ACROSS PARTS OF NRN AND ERN OK.
   
   THE CONVECTION ONGOING IN NRN OK IS LOCATED ALONG AN OUTFLOW
   BOUNDARY AND IS ON THE NRN EDGE OF A GRADIENT OF MODERATE TO STRONG
   INSTABILITY. THE SMALL CLUSTER OF STORMS IS LIKELY ASSOCIATED WITH A
   WEAK DISTURBANCE EVIDENT ON WATER VAPOR IMAGERY AND IS EXPECTED TO
   RIDE ESEWD ALONG THIS GRADIENT FOR SEVERAL MORE HOURS. THE LATEST
   PROFILER AT TULSA SHOWS ABOUT 35 KT OF VERTICAL SHEAR AND THE SHEAR
   SHOULD BECOME SLIGHTLY MORE FAVORABLE AS THE LOW-LEVEL JET INCREASES
   TONIGHT. THIS COMBINED WITH THE INSTABILITY SHOULD SUSTAIN THE
   CLUSTER EWD ACROSS NERN OK. ALTHOUGH THE ACTIVITY MAY BE SLIGHTLY
   ELEVATED...DOWNDRAFTS SHOULD BE STRONG ENOUGH FOR AN ISOLATED WIND
   DAMAGE THREAT. HAIL WILL ALSO ACCOMPANY THE MORE INTENSE CELLS.
   
   ..BROYLES.. 05/01/2009
   
   
   ATTN...WFO...TSA...OUN...
   
   LAT...LON   34669766 34679810 34859810 34839860 35119864 35109974
               35029974 35029997 36589994 36599926 36799931 36769912
               36529894 36399860 36479850 36469808 36169808 36169715
               36279717 36269682 36179685 36179664 35449663 35439645
               35129641 35099648 34909648 34949692 34849694 34859764
               34669766