MESOSCALE PRECIPITATION DISCUSSION 0082
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1226 PM EST SAT MAR 12 2016
 
AREAS AFFECTED...FAR EAST TX...LA 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 121730Z - 122130Z
 
SUMMARY...INCREASING COVERAGE OF CONVECTION ASSOCIATED WITH THE
UPPER LOW EXITING TX COULD PRODUCE LOCALLY HEAVY RAINFALL ACROSS
PORTIONS OF FAR EAST TX AND LA...IN LOCATIONS WHERE SOILS ARE
SATURATED. FLASH FLOODING IS POSSIBLE

DISCUSSION...THE REGIONAL RADAR MOSAIC IS SHOWING A GENERAL
INCREASE IN CONVECTIVE COVERAGE ACROSS FAR EAST TX INTO PORTIONS
OF CENTRAL AND SOUTHERN LA (AS WELL AS THE GULF COAST WATERS SOUTH
OF THESE AREAS). THE CONVECTION IS DEVELOPING IN AN AXIS OF SCAPE
VALUES BETWEEN 500 AND 1000 J/KG. THE ACTIVITY IS TAPPING 1.00 TO
1.25 INCH PRECIPITABLE WATER AS IT TRACKS NORTH AHEAD OF THE
EXITING UPPER LOW...LOCATED OVER NORTHEAST TX. 

TO THIS POINT...HOURLY RAINFALL RATES HAVE GENERALLY REMAINED
BELOW AN INCH WITH THE DEVELOPING ACTIVITY. HOWEVER...THE
CONVECTION IS LOW TOPPED...AND MODEL SOUNDINGS ACROSS PORTIONS OF
EAST TX/WESTERN LA SHOWED A MOIST COLUMN UP THROUGH 700/500
MB...WHICH WOULD SUGGEST  FAIRLY EFFICIENT RAINFALL PRODUCERS.
BECAUSE OF THE EFFICIENCY OF THE ENVIRONMENT...HOURLY RAINFALL
RATES COULD TICK UPWARD OF 1.50 INCHES WITH HEAVIER
CELLS...ESPECIALLY ACROSS FAR EAST TX IN WESTERN AND NORTHWEST LA. 

IN ADDITION...THE MEAN 850-300 MB FLOW AND CORFIDI VECTORS ARE ARE
NEARLY ALIGNED... WHICH WOULD PROMOTE TRAINING AND BACKBUILDING OF
CELLS. THIS ALREADY APPEARS TO BE OCCURRING OVER FAR EAST TX/FAR
WESTERN LA. TRAINING COULD RESULT IN LOCAL 2+ INCH RAINFALL
AMOUNTS...WHICH IS IN GENERAL AGREEMENT WITH MUCH OF THE HIGH
RESOLUTION GUIDANCE. 

NEEDLESS TO SAY...THESE AREAS (PARTICULARLY NORTHERN AND WESTERN
LA) HAVE SEEN TREMENDOUS AMOUNTS OF RAINFALL IN THE PAST WEEK.
WHILE ONE AND THREE HOUR FLASH FLOOD GUIDANCE VALUES HAVE
RECOVERED...SATURATED SOILS LIKELY REMAIN OVER PORTIONS OF EAST TX
INTO MUCH LA. ANY HEAVY RAINFALL COULD RESULT IN ADDITIONAL
FLOODING...OR EXACERBATION OF CURRENT FLOODING. 

HAYES

ATTN...WFO...HGX...JAN...LCH...LIX...LZK...SHV...

ATTN...RFC...ABRFC...LMRFC...WGRFC...

LAT...LON   33789385 33589326 33219254 32809203 32689188 
            32249149 31479113 30569088 29769118 29519167 
            29709407 30419464 32379538 32789535 33159511 
            33719431