MESOSCALE DISCUSSION 0015
   NWS STORM PREDICTION CENTER NORMAN OK
   0827 PM CST SUN JAN 09 2011
   
   AREAS AFFECTED...CNTRL AL...W CNTRL GA
   
   CONCERNING...WINTER MIXED PRECIPITATION 
   
   VALID 100227Z - 100700Z
   
   MIXED PRECIP RATES WILL INCREASE THROUGH THE EVENING ACROSS PORTIONS
   OF CNTRL AL INTO W CNTRL GA. PRECIP TYPE IS EXPECTED TO BE FZRA
   PRIMARILY S OF I-20...WITH A TRANSITION TO SLEET FURTHER NORTH. 
   
   EARLY EVENING WV IMAGERY SHOWS A COMPACT UPPER LOW CENTERED NEAR THE
   ARKLATEX REGION...WITH REGIONAL RADARS INDICATING A BROAD PRECIP
   SHIELD AHEAD OF THE SYSTEM ACROSS THE DEEP SOUTH. PRECIP OVER
   E-CNTRL AL INTO W-CNTRL GA HAS BEEN SLOW TO ACCUMULATE THUS FAR DUE
   TO THE CONTINUED LOW-LEVEL ADVECTION OF COLD DRY AIR INTO THE REGION
   BY HIGH PRESSURE OVER THE OHIO VALLEY. HOWEVER...CONSIDERABLE
   TOP-DOWN MOISTENING WAS OBSERVED BETWEEN 09/18Z AND 10/00Z SOUNDINGS
   AT BMX AND FFC. AS PRECIP CONTINUES TO FALL...FURTHER MOISTENING
   WILL ALLOW RATES TO INCREASE...WITH HOURLY LIQUID EQUIVALENT AOA
   0.05 IN/HR POSSIBLE BY 03Z-06Z. 
   
   THE PRECIP SHIELD IS BEING DRIVEN BY UPGLIDE OVER THE LOW LEVEL COLD
   AIR DOME IN ASSOCIATION WITH A STRONG 55-60 KT LOW-LEVEL JET...AS
   SAMPLED BY THE 00Z LIX SOUNDING. WHILE SOME SNOW IS POSSIBLE EARLY
   THIS EVENING OVER THE MCD AREA...CONTINUED WAA IN THE 900-700 MB
   LAYER SHOULD ALLOW A CHANGEOVER TO SLEET LATER THIS EVENING...WITH
   FZRA BECOMING DOMINANT MAINLY SOUTH OF THE I-20 CORRIDOR LATER
   TONIGHT AFTER 06Z. 
   
   A MID-LEVEL DRY SLOT /AS NOTED ON WV IMAGERY/ WILL OVERTAKE THE AREA
   LATER THIS EVENING...BUT RELATIVELY STEEP LAPSE RATES /6.5-7 C/KM/
   ASSOCIATED WITH THIS FEATURE COMBINED WITH CONTINUED STRONG WAA WILL
   ALLOW PRECIP OF A MORE CONVECTIVE NATURE TO DEVELOP...WITH LIQUID
   EQUIVALENT RATES AOA 0.10 IN/HR POSSIBLE IN HEAVIER SHOWERS.
   
   ..DEAN.. 01/10/2011
   
   
   ATTN...WFO...FFC...BMX...HUN...MOB...
   
   LAT...LON   32228782 32618811 32968820 33338824 33698817 33988786
               34078707 34128627 34128547 34088442 33708389 33368350
               33108347 32868377 32608423 32498463 32388528 32258572
               32188651 32198702 32228782