MESOSCALE DISCUSSION 0842
   NWS STORM PREDICTION CENTER NORMAN OK
   0329 PM CDT FRI MAY 09 2008
   
   AREAS AFFECTED...TN...PARTS OF NRN AL/NW MS INTO ERN/CNTRL AR
   
   CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 
   
   VALID 092029Z - 092230Z
   
   IT IS NOT CERTAIN THAT A WW WILL BE NEEDED.  BUT...TRENDS ARE BEING
   MONITORED FOR THE POSSIBILITY OF AN INCREASING SEVERE THREAT.
   
   CONVECTION IS BEGINNING TO DEEPEN/INTENSIFY IN ZONE OF STRONGER
   LOWER/MID TROPOSPHERIC WARM ADVECTION ON THE SOUTH/SOUTHWESTERN
   PERIPHERY OF A LOW AMPLITUDE SHORT WAVE IMPULSE PROGRESSING THROUGH
   THE LOWER OHIO VALLEY.  MID-LEVEL SUBSIDENCE/WARMING APPEARS TO BE
   SUPPRESSING DEVELOPMENT ALONG A LOW-LEVEL BAROCLINIC ZONE EXTENDING
   WEST OF ONGOING ACTIVITY INTO PARTS OF NORTHEAST/CENTRAL ARKANSAS.
   THIS IS WHERE LATEST RUC GUIDANCE SUGGESTS THAT INHIBITION FOR MIXED
   BOUNDARY LAYER PARCELS WITH CAPE IN EXCESS OF 1000 J/KG IS BECOMING
   NEGLIGIBLE IN RESPONSE TO DAYTIME HEATING.  BUT...AS UPPER WAVE
   CONTINUES TO PASS TO THE NORTH...IT APPEARS POSSIBLE THAT SUFFICIENT
   COOLING ALOFT MAY OCCUR FOR INCREASING CONVECTIVE DEVELOPMENT
   BETWEEN NOW AND 22-23Z.  IN THE PRESENCE OF STRONG DEEP LAYER SHEAR
   ASSOCIATED WITH A BROAD BELT OF 50+ KT 500 MB FLOW... ISOLATED
   SUPERCELLS ARE POSSIBLE...PRIMARILY WITH A RISK FOR LARGE HAIL AND
   LOCALIZED DAMAGING WIND GUSTS.
   
   ..KERR.. 05/09/2008
   
   
   ATTN...WFO...MRX...OHX...HUN...PAH...MEG...LZK...
   
   34449332 35699197 36448919 36418628 36058508 35028510
   34958658 34928781 34698972 34229110 33919254 34029319