MESOSCALE PRECIPITATION DISCUSSION 0014
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
946 PM EDT SUN APR 06 2014
 
AREAS AFFECTED...NERN LA...CNTRL/SRN MS...CNTRL/SRN AL 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY 
 
VALID 070140Z - 070530Z
 
SUMMARY...THE FLASH FLOOD THREAT CONTINUES ACROSS THE GULF COAST
STATES AS LINEAR BANDS OF CONVECTION CONTINUE TO LOCALLY TRAIN
OVER THE SAME AREA...INVOLVING ALREADY SATURATED SOIL.

DISCUSSION...THE LATEST IR/WV SATELLITE IMAGERY SHOWS A VERY
DIFFLUENT FLOW PATTERN ACROSS THE GULF COAST STATES OUT AHEAD OF A
STRONG SRN STREAM UPPER TROUGH THAT IS EJECTING EAST ACROSS THE
SRN PLAINS ATTM. A VERY WELL-DEFINED SUBTROPICAL JET INVOLVED WITH
THIS IS PROVIDING MOISTURE TRANSPORT IN THE MID/UPPER LVLS OF THE
ATMOSPHERE WHILE LOW LVL INFLOW INCREASES OFF THE GULF OF MEXICO.
THE LATEST GOES-SOUNDER DATA SHOWS PWATS ON THE ORDER OF 1.6 TO
1.8 INCHES ACROSS CNTRL/SRN LA...CNTRL/SRN MS AND CNTRL/SRN AL.
THIS COUPLED WITH A GRADUALLY NWD LIFTING WARM FRONT IS
CONTRIBUTING TO DEEP LAYER ASCENT AND GIVEN A FAVORABLE
THERMODYNAMIC ENVIRONMENT INTERACTING WITH THE BOUNDARY...THERE
ARE NUMEROUS CLUSTERS OF COLD-TOPPED CONVECTION AND SOME LINEAR
BANDS OF CONVECTION WHICH ARE ALIGNED NEARLY PARALLEL TO THE
LOW/MID LVL FLOW. CONSEQUENTLY...THERE ARE AREAS OF TRAINING
CONVECTION...AND GIVEN ALREADY SATURATED SOILS FRONT EARLIER RAINS
IN THE DAY...THERE IS AN ELEVATED RISK FOR ADDITIONAL FLASH
FLOODING.

THE LATEST HIRES GUIDANCE INCLUDING THE 12Z ARW/12Z NMM AND 18Z
GEM REGIONAL SUPPORT A CONTINUATION OF STRONG CONVECTION
OVERNIGHT...WITH RISK OF CELL MERGERS AND LINEAR BANDS OF
CONVECTION THAT WILL LIKELY TRAIN OVER THE SAME AREA. RAINFALL
RATES HAVE BEEN REPORTED TO BE LOCALLY OVER 2 INCHES/HR...AND WITH
A 50 TO 60 KT LOW LVL JET EMANATING OFF THE GULF OF MEXICO AND THE
AFOREMENTIONED PWATS...INTENSE RAINFALL RATES WILL CONTINUE MUCH
OF THE NIGHT.

ORRISON

ATTN...WFO...TAE...BMX...MOB...MEG...JAN...LIX...LCH...SHV...

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

LAT...LON   30979283 30759228 30979115 31309021 31428904 30988740
            30728630 30878558 31378513 32388517 33078552 33578656
            33798799 33678980 33239150 32749271 32009325 31509326
            30979283