MESOSCALE PRECIPITATION DISCUSSION 0319
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
410 PM EDT MON JUN 06 2016
 
AREAS AFFECTED...NORTHERN GA & THE WESTERN CAROLINAS 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 062009Z - 070209Z
 
SUMMARY...PULSE THUNDERSTORMS ARE SHOWING SOME BACKBUILDING
CHARACTERISTICS WITHIN AN UNUSUAL ENVIRONMENT.  WITH HOURLY RAIN
RATES UP TO 2.5" POSSIBLE, FLASH FLOODING IS POSSIBLE.

DISCUSSION...TROPICAL STORM COLIN APPEARS LIKE AN OCCLUDED CYCLONE
IN THE THERMAL FIELD AND WITHIN VISIBLE SATELLITE IMAGERY, WITH A
BAROCLINIC LEAF STRUCTURE ACROSS THE FL PANHANDLE, MUCH OF GA, AND
SC.  ON THE NORTHWEST FRINGE OF THE DEEPER CLOUDS, PULSE
THUNDERSTORMS ARE FORMING FROM NORTHEAST AL ACROSS NORTHERN GA AND
THE WESTERN CAROLINAS, WHICH ARE SHOWING BACKBUILDING CHARACTER. 
THIS APPEARS TO BE DUE TO THE INVERTED THERMAL FIELD ACROSS THE
DEW POINT BOUNDARY IN THE REGION, WITH WARMER AND MORE UNSTABLE
AIR IN ITS WAKE TO ITS WEST AND NORTHWEST, WHERE MLCAPES ARE
500-1000 J/KG.  PRECIPITABLE WATER VALUES OF 1.5-2" LIE HERE, PER
RAP FORECAST MASS FIELDS.  A SHORTWAVE MOVING ACROSS AL APPEARS TO
BE PROVIDING A BOOST TO UPWARD MOTION IN THE REGION.

RAP MASS FIELDS INDICATE THAT THE DEW POINT GRADIENT WILL RETREAT
NORTHWEST OVER NEXT SEVERAL HOURS IN THE DIRECTION OF THE
INSTABILITY.  THIS BOUNDARY SHOULD CONTINUE TO EXHIBIT
BACKBUILDING CELLS AS IT SLOWLY SHIFTS NORTHWEST, WHICH COULD
OCCASIONALLY SHOW SOME ORGANIZATION AS BULK SHEAR VALUES IN THE
0-6 KM LAYER ARE 30-40 KTS.  THE 12Z SSEO NEIGHBORHOOD
PROBABILITIES IMPLY ISSUES WOULD REACH A MAXIMUM IN THE 22-01Z
WINDOW.  GALVEZ-DAVISON INDEX VALUES MAXIMIZE AROUND 21Z.
CONSIDERING THE ABOVE, CELL COVERAGE SHOULD INCREASE OVER THE NEXT
FEW HOURS.  THE MESOSCALE/CAM GUIDANCE WHICH SHOWS A SIGNAL FOR IT
SHOWS LOCAL AMOUNTS IN THE 3-5" RANGE, WHICH COULD FALL QUICKLY. 
SHOULD THE CELLS SHOW SOME LONGEVITY OR START TO MERGE, HOURLY
RAIN RATES UP TO 2.5" WOULD BE POSSIBLE.  OTHERWISE, 1.5" AN HOUR
RAIN RATES WOULD BE PAR FOR THE COURSE.  AFTER SUNSET, THIS
CONVECTION SHOULD WANE AS INSTABILITY BEGINS TO FALTER.  DUE TO
THE UNCERTAINTY, KEPT THE MPD CATEGORY AS POSSIBLE FLASH FLOODING.

ROTH

ATTN...WFO...BMX...CAE...FFC...GSP...HUN...MRX...RAH...RNK...

ATTN...RFC...LMRFC...OHRFC...SERFC...

LAT...LON   36738035 36637925 36107828 35227920 33658253 
            33628641 34438628 35428429 35868289