MESOSCALE DISCUSSION 2060
   NWS STORM PREDICTION CENTER NORMAN OK
   0745 AM CST FRI DEC 25 2015

   AREAS AFFECTED...PORTIONS OF CENTRAL MISSISSIPPI...NORTHEAST
   LOUISIANA...EXTREME SOUTHEAST ARKANSAS...WEST-CENTRAL/NORTHERN
   ALABAMA

   CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

   VALID 251345Z - 251615Z

   PROBABILITY OF WATCH ISSUANCE...40 PERCENT

   SUMMARY...PORTIONS OF THE ARKLAMISS REGION TO W-CNTRL/NRN AL ARE
   BEING MONITORED FOR AN INCREASE IN THE SVR-TSTM POTENTIAL THIS
   MORNING. IT IS POSSIBLE THAT WW ISSUANCE MAY BE NEEDED THIS MORNING.

   DISCUSSION...RECENT TRENDS IN MOSAIC RADAR IMAGERY SUGGEST
   CONVECTION BECOMING INCREASINGLY AGITATED WITHIN BROADLY CONFLUENT
   LOW-LEVEL SLY FLOW FROM SRN LA INTO SRN MS. UPDRAFTS ARE ALREADY
   REACHING EQUILIBRIUM LEVELS AS EVIDENCED BY A RECENT INCREASE IN CG
   LIGHTNING NEAR AND SW OF BROOKHAVEN MS. SFC OBSERVATIONS SUGGEST
   THAT THIS ACTIVITY IS EVOLVING WITHIN A NWD ACCELERATION OF
   UNSEASONABLY RICH LOW-LEVEL MOISTURE -- E.G. LIX 12Z RAOB SAMPLING
   17.0 G/KG MEAN MIXING RATIO. WITH WEAK MLCINH...AND MODERATE
   INSTABILITY ALREADY IN PLACE...IT MAY TAKE LITTLE SFC HEATING FOR
   NWD DEVELOPING CONVECTION TO DEEPEN. THE GLANCING INFLUENCE OF A
   SHEARING...LOW-AMPLITUDE MIDLEVEL IMPULSE CROSSING THE MID-SOUTH MAY
   ALSO BE RELATED TO THE ONGOING UPTICK IN CONVECTION...AND ITS
   ASSOCIATED UPWARD-MOTION FIELDS MAY FOSTER CONTINUED CONVECTIVE
   GROWTH THIS MORNING -- AS SHOWERS/TSTMS EVOLVE TOWARD THE INTERSTATE
   20 CORRIDOR.

   FARTHER NORTH...FROM EXTREME SERN AR EWD/ENEWD TO W-CNTRL/NRN
   AL...ABUNDANTLY MOIST LOW-LEVEL INFLOW CONTINUES TO FEED THE
   WSWWD-TRAILING SEGMENT OF AN MCS WHOSE LEADING EDGE IS CROSSING
   PARTS OF THE TN VALLEY. DESTABILIZATION ON THE WARM SIDE OF THE
   COLD-POOL-ENHANCED BAROCLINIC ZONE MAY FOSTER AN UPTICK IN
   CONVECTION THROUGH THE MORNING...IN ADDITION TO INTENSIFICATION OF A
   QUASI-LINEAR BAND OF CONVECTION IMMEDIATELY S FROM NEAR GREENWOOD TO
   S OF TUPELO.

   THE WIND PROFILE SAMPLED BY THE 12Z JACKSON MS RAOB SUGGESTS AMPLE
   LOW-LEVEL AND DEEP SHEAR...WITH AROUND 300 M2/S2 OF SRH IN THE
   LOWEST 1 KM AGL. IF SFC HEATING COMBINED WITH SOME PERIPHERAL ASCENT
   TO THE MID-LEVEL IMPULSE WERE TO BECOME SUFFICIENT FOR CONVECTION TO
   MORE STRONGLY DEEPEN/PERSIST...THE RISK FOR SVR TSTMS INCLUDING
   TORNADOES WOULD INCREASE -- PERHAPS THIS MORNING. HOWEVER...GIVEN
   THE TENDENCY FOR THE IMPULSE TO BE MOVING AWAY FROM STRONGER
   BUOYANCY AS DIURNAL HEATING COMMENCES...THE OVERALL SVR-TSTM
   POTENTIAL THIS MORNING IS UNCERTAIN...AND CONVECTIVE TRENDS WILL
   CONTINUE TO BE MONITORED.

   ..COHEN/CORFIDI.. 12/25/2015


   ATTN...WFO...BMX...HUN...MEG...JAN...SHV...

   LAT...LON   32888777 31978934 31739051 31829155 32269200 32919184
               33549089 34428800 34368713 34048684 33478702 32888777