MESOSCALE PRECIPITATION DISCUSSION 0779
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1028 PM EST TUE NOV 29 2016
 
AREAS AFFECTED...NORTHEASTERN LA/CENTRAL MS/NORTHERN AL/CENTRAL
TN... 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 300327Z - 300727Z
 
SUMMARY...STRONG DYNAMICS ACCOMPANYING THE SUBTROPICAL JET
STREAMING TOWARD THE MID-SOUTH HAS FOCUSED A MODERATE/HEAVY BAND
OF RAINFALL ACROSS THE REGION. A GENERAL SOUTHWEST TO NORTHEAST
ORIENTATION HAS ALLOWED FOR REGENERATION OF CELLS ALONG THE
PRECIPITATION AXIS. EXPECT THE POTENTIAL FOR FLASH FLOODING TO
CONTINUE WITH A NEW AREA POSSIBLY EMERGING BACK TOWARD THE LA/MS
BORDER WHERE SUPERCELLS ARE ALIGNING WITH THE MEAN STEERING FLOW. 

DISCUSSION...THE 03Z SURFACE ANALYSIS SHOWED A SLOW-MOVING COLD
FRONT TRACKING THROUGH THE OZARKS AND BACK TOWARD THE ARKLATEX
REGION. IN ADVANCE OF THIS REGION...A HIGHLY BUOYANT AIR MASS
WHERE ANOMALOUS MOISTURE CONTINUES TO PUMP NORTHWARD FROM THE GULF
OF MX HAS FOCUSED ABUNDANT CONVECTION OVER THE MID-SOUTH DOWN
TOWARD THE LOWER MS VALLEY. WHILE THE NORTHERN BATCH OF RAINFALL
HAS BECOME ELEVATED IN NATURE...CONVECTION IS MORE ROOTED IN THE
BOUNDARY LAYER WITH A NUMBER OF SUPERCELLS OBSERVED OVER CENTRAL
MS/LA. IN THIS REGION...1000 TO 1500 J/KG OF MLCAPE HAVE BEEN
OBSERVED VIA THE 03Z RAP OBJECTIVE ANALYSIS. THIS COMBINATION OF
AMPLE INSTABILITY...ABUNDANT MOISTURE (ABOVE THE 90TH PERCENTILE
ACROSS JACKSON MS)...AND NEARLY UNIDIRECTIONAL FLOW FROM ROUGHLY
750-MB UPWARD WILL SUPPORT A HEAVY RAINFALL THREAT CAPABLE OF
PRODUCING A FLASH FLOOD. WHILE FFG VALUES ARE GENERALLY QUITE
HIGH...SOME OF THE LOCAL RAINFALL RATES MAY BE HIGH ENOUGH TO
CAUSE SOME HYDROLOGIC ISSUES. AMONG THE AVAILABLE CAMS...THE LAST
FEW RUNS OF THE HRRR HAVE BEEN CONSISTENT IN PAINTING HEAVY
AMOUNTS FROM EASTERN LA UP THROUGH CENTRAL MS/NORTHERN AL AND INTO
CENTRAL TN. EXPECT GENERAL HOURLY RATES APPROACHING 1 TO 1.50
INCHES WITHIN SOME OF THE HEFTIER CORES BASED ON RECENT MESONET
DATA.


RUBIN-OSTER

ATTN...WFO...BMX...HUN...JAN...LCH...LIX...MEG...MRX...OHX...
SHV...

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

LAT...LON   36608606 36378503 35108542 33968717 33118881 
            32678957 32189030 31559099 30969156 31219216 
            31999209 32769137 33219090 34778789 35668656