MESOSCALE PRECIPITATION DISCUSSION 0016
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
307 PM EST THU JAN 21 2016
 
AREAS AFFECTED...NLOUISIANA...CENT MISSISSIPPI...NW ALABAMA 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 212006Z - 220206Z
 
SUMMARY...FAVORED ORIENTATION FOR TRAINING CELLS JUST NORTH OF
STATIONARY FRONT IN ADVANCE OF STRONGER CONVECTION.

DISCUSSION...WV LOOP/RADAR MOSAIC PRESENTING A STRENGTHENING
CYCLONE ACROSS NE TX PROVIDING SIGNIFICANT HEIGHT FALLS AND
SURFACE CYCLOGENESIS...NEAR KSHV ATTM. FROM THE LOW A NEAR
STATIONARY FRONT DRAPES ACROSS N LA BEFORE ORIENTING NE ACROSS
CENTRAL MS. SOUTH OF THE BOUNDARY DECENT MOISTURE AVAILABILITY
WITH SFC TDS IN THE MID 60S AND TPWS NEAR 1.0-1.25" AS WELL AS
INCREASING INSTABILITY WITH DAY TIME HEAT AS SBCAPES ARE
INCREASING TO 1500-2500 J/KG.  STRONG/STRENGTHENING LOW LEVEL SWLY
FLOW IS PROVIDING ISENTROPIC ASCENT FOR CONVECTIVE DEVELOPMENT
ALONG AND JUST NORTH OF THE FRONT.  ALOFT... INCREASING DIFFLUENCE
WITH A STRENGTHENING RIGHT ENTRANCE DYNAMICS FROM 120 KT JET IN
THE TENNESSEE RIVER VALLEY...NOT ONLY SUPPORTS LARGER SCALE ASCENT
AND EVACUATION OF CONVECTION BUT ALSO IS SUPPORTIVE OF A DEEP SWLY
CELL MOTIONS THAT ARE FAIRLY PARALLEL TO THE FRONTAL ZONE.  THIS
IS CURRENTLY SUPPORTING SHALLOWER/MORE SCATTERED CELLS THAT ARE
WITHIN A FAVORABLE TRAINING PROFILE FOR THE NEXT 3-5HRS.  THOUGH
RATES ARE NOT PARTICULARLY ROBUST (BEING ELEVATED AND SHALLOWER)
ARE GENERALLY 1.0"/HR PROVIDING TOTALS UP TO 1.0"...BUT WITH
TRAINING TOTALS COULD REACH 2-3" IN ISOLATED SPOTS ACROSS CENTRAL
MS INTO NW AL.  THIS IS SUGGESTED BY FAVORED HI-RES CONVECTIVE
ALLOWING GUIDANCE SUCH AS THE 12Z NSSL-WRF, ARW AND 17Z ERSL
EXPERIMENTAL HRRR.  

TO FURTHER COMPOUND FLOODING CONCERNS... STRONGER/COLDER CELLS
ALONG THE PRE-COLD FRONT SQUALL LINE WITH BETTER MST
CONVERGENCE...ARE CAPABLE OF RATES UP TO 2"/HR...WILL ALSO TRACK
NEAR THE TRIPLE-POINT/SURFACE LOW ACROSS N LA/W CENTRAL MS.  WITH
INITIAL ROUNDS OF CELLS REDUCING HIGHER FFG VALUES...THESE
STRONGER CELLS MAY LEAD TO ISOLATED FLASH FLOODING CONCERNS.

GALLINA

ATTN...WFO...BMX...HUN...JAN...LCH...MEG...SHV...

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

LAT...LON   34518851 34518720 33488757 32288971 31449155 
            31109273 32039334 33069142 33749016