MESOSCALE PRECIPITATION DISCUSSION 0643...CORRECTED
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1106 AM EST SAT NOV 07 2015
 
CORRECTED FOR GRAPHIC

AREAS AFFECTED...SOUTHEAST TX...SOUTHWEST/CENTRAL LA 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 071530Z - 071930Z
 
SUMMARY...INTENSE AND SLOW-MOVING SHOWERS WILL CONTINUE OVER THE
NEXT SEVERAL HOURS AND WITH INTENSE RAINFALL RATES EXCEEDING 2
INCHES/HR...FLASH FLOODING WILL BE POSSIBLE.

DISCUSSION...THE LATEST WV SATELLITE IMAGERY SHOWS A SHORTWAVE
TROUGH WITH A SUBTROPICAL ORIGIN EJECTING NORTHEAST ACROSS CENTRAL
TX THIS MORNING...AND THIS ENERGY IS INTERACTING WITH A SURFACE
COLD FRONT THAT IS SLOWLY PUSHING SOUTHEAST ACROSS THE GULF COAST
STATES. WIDESPREAD AND LOCALLY HEAVY SHOWERS HAVE BEEN OCCURRING
THIS MORNING ACROSS MUCH OF SOUTHEAST TX AND WELL NORTHEAST
THROUGHOUT THE LOWER MS VALLEY.

THERE HAS BEEN SOME SUBTLE COOLING NOTED IN THE CLOUD TOPS OVER
THE LAST COUPLE OF HOURS OVER SOUTHEAST TX WHICH APPEARS TO BE
REFLECTIVE OF THE STRONGER DEEP LAYER ASCENT ASSOCIATED WITH THE
SHORTWAVE TROUGH AND UPPER JET DYNAMICS. WHILE INSTABILITY IS VERY
LIMITED...AND FOCUSED GENERALLY ALONG THE GULF COAST AND
OFFSHORE...THE UPTICK IN DEEPER LAYER FORCING AND CONVERGENCE NEAR
THE FRONT IS FOCUSING SOME AREAS OF INTENSE CONVECTIVE RAINS. THIS
HAS PARTICULARLY BEEN NOTED THAT LAST COUPLE OF HOURS ACROSS
EXTREME SOUTHEAST TX FROM NEAR CORPUS CHRISTI TO GALVESTON AND UP
THE COAST TO THE BEAUMONT-PORT ARTHUR AREA. HEAVY RAINS ALSO
EXTEND NORTHEAST INTO CENTRAL LA...AND ALL OF THIS ACTIVITY
APPEARS TO BE ENHANCED RIGHT ALONG A WELL-DEFINED 850 MB
FRONT/TROUGH AXIS WHICH IS MOVING VERY LITTLE FOR THE TIME BEING.

OVER THE NEXT FEW HOURS...THERE IS A CONCERN FOR LOCALLY VERY
HEAVY RAINFALL AMOUNTS ALONG THE UPPER TX COAST AND INLAND ACROSS
PARTS OF SOUTHWEST AND CENTRAL LA. THE LATEST HRRR SUGGESTS THE
POTENTIAL FOR 3 TO 6 INCHES OF RAIN THROUGH ABOUT 19Z...WITH
ISOLATED HEAVIER AMOUNTS. GIVEN VERY SLOW-CELL MOTION AND
POTENTIAL FOR CELL TRAINING...THESE AMOUNTS APPEAR TO BE
REALISTIC. FURTHERMORE...THE LATEST GOES-SOUNDER AND GPS-DERIVED
PWATS ARE RUNNING FROM ABOUT 1.9 TO 2.1 INCHES...WHICH WILL DRIVE
RAINFALL RATES IN EXCESS OF 2 INCHES/HR. THEREFORE...FLASH
FLOODING WILL BE POSSIBLE.

ORRISON

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

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

LAT...LON   31769242 31599172 31089152 30509177 29949237 
            29579313 29319398 28919479 28519560 27659685 
            27639737 27899753 28349730 28929624 29429538 
            30049451 30479413 31289341