MESOSCALE DISCUSSION 2280
   NWS STORM PREDICTION CENTER NORMAN OK
   0755 PM CDT SUN OCT 30 2011
   
   AREAS AFFECTED...THE MIAMI AREA
   
   CONCERNING...HEAVY RAINFALL 
   
   VALID 310055Z - 310300Z
   
   A 10-15-MILE-WIDE AREA OF HEAVY-RAIN-PRODUCING CONVECTION CENTERED
   OVER BISCAYNE BAY NEAR PINECREST WILL LIKELY REMAIN QUASI-STATIONARY
   DURING THE NEXT FEW HOURS. THIS WILL AFFECT PORTIONS OF THE MIAMI
   AREA NEAR AND SOUTH OF CORAL GABLES TOWARD PERRINE AND CUTLER
   RIDGE...WITH ADDITIONAL HEAVY RAIN POSSIBLY OCCURRING AFTER 0130Z
   FARTHER NORTHEAST TOWARD MIAMI BEACH AND DOWNTOWN MIAMI.
   
   SFC MESOANALYSIS AT 00Z DEPICTS THAT THE CONVECTION IS ANCHORED TO A
   NEARLY STATIONARY FRONT ORIENTED WSW-ENE ACROSS THE SRN FL
   PENINSULA. ELY INFLOW OF 20-25 KT WITHIN THE 925-850-MB LAYER PER
   MIAMI 00Z RAOB WILL OPPOSE THE WLY COMPONENT OF FLOW DEEPER IN THE
   CLOUD-BEARING LAYER TO LIMIT STORM MOTION. MEANWHILE...A
   CONVECTIVELY INDUCED MCV WITHIN THE 3-6-KM-LAYER /PER KEY WEST
   WSR-88D DATA/ WILL EXPERIENCE LITTLE STEERING FLOW PER VWP
   DATA...THUS PROVIDING QUASI-STATIONARY FORCING FOR REGENERATIVE
   CONVECTION. THESE FACTORS WILL YIELD LITTLE STORM MOTION...WITH
   PERSISTENT HEAVY RAIN OVER MULTIPLE HOURS POSSIBLE. WITH THE 00Z
   MIAMI RAOB INDICATING A 4.5-KM DEEP...SATURATED WARM-CLOUD
   LAYER...COLLISION-COALESCENCE PROCESS WITHIN ABUNDANT DEEP-LAYER
   MOISTURE /PW VALUE OF 2.23 INCHES/ WILL SUPPORT HEAVY RAINFALL RATES
   OF 2-4 IN/HR. IF THE STORM IS ABLE TO DEEPEN AND EXPERIENCE STRONGER
   SWLY FLOW WITHIN THE MID/UPPER LEVELS...IT WOULD GRADUALLY SHIFT
   NEWD TOWARD DOWNTOWN MIAMI AND MIAMI BEACH...MAINLY AFTER 0130Z.
   WHILE CONVECTION MAY OCCASIONALLY EXHIBIT A MID-LEVEL
   CIRCULATION...WEAK LOW/MID-LEVEL LAPSE RATES AND WEAK LOW-LEVEL
   SHEAR WILL GREATLY MITIGATE THE SVR POTENTIAL.
   
   ..COHEN.. 10/31/2011
   
   
   ATTN...WFO...MFL...
   
   LAT...LON   25428017 25458042 25608056 25778051 25868030 25788012
               25578008 25428017