MESOSCALE PRECIPITATION DISCUSSION 0590...CORRECTED
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
238 PM EDT SUN AUG 21 2016
 
CORRECTED FOR GRAPHIC

AREAS AFFECTED...PORTIONS OF SOUTH-CENTRAL/SOUTHERN AND SOUTHEAST
TX 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 211837Z - 220000Z
 
SUMMARY...ADDITIONAL CLUSTERS OF HEAVY RAIN ARE EXPECTED THROUGH
THE AFTERNOON. ADDITIONAL FLASH FLOODING CONCERNS WILL EXIST GIVEN
THE WET ANTECEDENT CONDITIONS.

DISCUSSION...IR SATELLITE IMAGERY HAS BEEN SHOWING COOLING
CONVECTIVE TOPS OVER PORTIONS OF SOUTH-CENTRAL AND SOUTHEAST TX IN
ASSOCIATION WITH A WEAK SURFACE LOW RIDING NORTHEAST UP ALONG A
FRONT DRAPED ACROSS THE REGION THAT IS FOCUSING DOWN TOWARD THE
GULF COAST.

THERE REMAINS A DEEP POOL OF TROPICAL MOISTURE IN VICINITY OF THE
FRONT...WITH PWATS AS HIGH AS 2.25 INCHES. MEANWHILE...THE LATEST
RAP ANALYSIS SHOWS A FAIR AMOUNT OF INSTABILITY POOLED ALONG THE
BOUNDARY WITH THE PERSISTENCE OF A MODEST LOW LEVEL SOUTHERLY
FETCH IN OFF THE GULF OF MEXICO THAT IS INTERACTING WITH AND
OVERRUNNING THE BOUNDARY.

THE FRONT SHOULD REMAIN ACTIVE WITH CONVECTION THROUGH THE
AFTERNOON AND INTO THE EARLY EVENING HOURS. THE LOW TO MID LEVEL
SOUTHERLY FLOW AHEAD OF THE SURFACE WAVE WILL PROMOTE SOME MODEST
N/S ORIENTED BANDS OF CONVECTION THAT WILL BE CAPABLE OF PRODUCING
ADDITIONAL HEAVY RAINFALL GIVEN THE INSTABILITY GRADIENT AND FOCUS
OF DEEP MOISTURE.

THE CIRA-LPW PRODUCT SHOWS MOISTURE HIGHLY CONCENTRATED IN THE
500/300 MB LAYER WHICH WILL ENHANCE RAINFALL EFFICIENCY AND THUS
THE RAINFALL RATES WHICH WILL LIKELY EXCEED 2.5 INCHES/HR WITHIN
THE STRONGER CORES. THE N/S ORIENTATION OF SOME OF THE BANDS WILL
ENHANCE THE POTENTIAL FOR TRAINING CELLS...AND THEREFORE THIS MAY
RESULT IN ADDITIONAL VERY HEAVY RAINFALL TOTALS.

AS PER RECENT HRRR/HRRRP GUIDANCE...EXPECT ADDITIONAL RAINFALL
AMOUNTS THROUGH 00Z OF AS MUCH AS 3 TO 5 INCHES...WITH ISOLATED
HEAVIER AMOUNTS. THESE RAINS WILL IMPACT SOME AREAS THAT SAW VERY
HEAVY RAINS LAST NIGHT...ESPECIALLY SOUTH AND EAST OF AN AREA FROM
AUSTIN TO SAN ANTONIO.
THUS...ADDITIONAL FLASH FLOODING WILL BE POSSIBLE GIVEN THE WET
ANTECEDENT CONDITIONS.

ORRISON

ATTN...WFO...BRO...CRP...EWX...HGX...

ATTN...RFC...WGRFC...

LAT...LON   30519775 30379683 30089649 29259620 28589636 
            27849700 27089746 26299779 26239832 26489876 
            27109875 27829850 28559842 29679838