MESOSCALE PRECIPITATION DISCUSSION 0212
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
445 AM EDT MON MAY 16 2016
 
AREAS AFFECTED...SOUTH TEXAS 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY 
 
VALID 160845Z - 161400Z
 
SUMMARY...VERY HEAVY RAINS CONTINUE EARLY THIS MORNING ACROSS
SOUTH TEXAS. SIGNIFICANT AND POTENTIALLY LIFE-THREATENING FLASH
FLOODING IS EXPECTED PAST DAWN.

DISCUSSION...VERY SLOW-MOVING SHOWERS AND THUNDERSTORMS ALONG THE
TX COAST AND AREAS JUST INLAND ACROSS THE COASTAL PLAIN FROM NEAR
CORPUS CHRISTI TO ROCKPORT HAVE RESULTED IN SIGNIFICANT RAINFALL
TOTALS OVER THE LAST SEVERAL HOURS...WITH DUAL-POL RADAR ESTIMATES
OF 4 TO 8 INCHES OF RAIN SINCE MIDNIGHT LOCAL TIME.

THE CONVECTION IS ASSOCIATED WITH THE ARRIVAL OF A SHORTWAVE
TROUGH THAT IS NOW CROSSING THE RIO GRANDE VALLEY AND MOVING INTO
SOUTH TEXAS WHERE IT IS INTERACTING WITH A STATIONARY FRONT AND A
WELL-DEFINED INSTABILITY GRADIENT. IN FACT...OVER THE LAST COUPLE
OF HOURS THERE ALSO HAS BEEN EVIDENCE OF A SURFACE LOW CENTER
DEVELOPING ALONG THIS FRONT NEAR CORPUS CHRISTI IN CONNECTION WITH
THE SHORTWAVE DYNAMICS AND STRONG LATENT HEAT ENERGY RELEASE
ASSOCIATED WITH THE CONVECTION. DUAL-POL RADAR OUT OF KCRP ALSO
INDICATES A STRENGTHENING MID LEVEL CIRCULATION NEAR THE TX COAST
WITH MULTIPLE EMBEDDED SMALL SCALE CIRCULATIONS.

OVER THE NEXT FEW HOURS...VERY HEAVY CONVECTIVE RAINS ARE EXPECTED
TO CONTINUE WITH THIS STRENGTHENING LOW TO MID LEVEL LOW
CENTER...AND SINCE IT IS EMBEDDED WITHIN A DEEP TROPICAL
ENVIRONMENT CHARACTERIZED BY 2 TO 2.25 INCH PWATS...RAINFALL RATES
WILL BE VERY HIGH AND MAY LOCALLY EXCEED 3 INCHES/HR.

THE FOCUS OF THE HEAVIEST RAINS SHOULD GRADUALLY LIFT NORTHEAST UP
ALONG THE MIDDLE TX COAST AWAY FROM CORPUS CHRISTI OVER THE NEXT 2
TO 3 HOURS AS PER LATEST HRRR GUIDANCE...BUT AREAS FROM NEAR
ROCKPORT ALL THE WAY UP TO PALACIOUS ARE LIKELY TO SEE ADDITIONAL
RAINFALL AMOUNTS OF 3 TO 6 INCHES BEFORE CONDITIONS IMPROVE TOWARD
MID MORNING. GIVEN THE SATURATED GROUNDS ACROSS THE
REGION...SIGNIFICANT FLASH FLOODING AND RUNOFF PROBLEMS ARE
EXPECTED.

ORRISON

ATTN...WFO...CRP...HGX...

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

LAT...LON   29499533 29029515 28689566 28239631 27949669 
            27579696 27339717 27339752 27439776 28089770 
            28799715 29289641 29489586