MESOSCALE PRECIPITATION DISCUSSION 0100
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
405 AM EDT MON MAY 18 2015
 
AREAS AFFECTED...LA...TX 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 180804Z - 181404Z
 
SUMMARY...CONVECTION CONTINUES TO EXPAND ALONG AND NORTH OF AN OLD
OUTFLOW BOUNDARY STRETCHING FROM NORTHEAST TX INTO NORTHERN
LOUISIANA.  EXPECT CONVECTION TO CONTINUE TO ENHANCE EARLY MONDAY
MORNING WITH INCREASING RUNOFF ISSUES POSSIBLE WITH TIME.


DISCUSSION...AN OUTFLOW BOUNDARY FROM EARLIER CONVECTION THAT HAS
MOVED INTO MS LIES IN A WEST TO EAST DIRECTION FROM NORTHEAST TX
INTO NORTHERN LA.  CONVECTION CONTINUES TO ENHANCE ALONG AND NORTH
OF THIS BOUNDARY IN THE GRADIENT OF HI MUCAPE VALUES OVER
NORTHEAST TX INTO CENTRAL LOUISIANA.  THE LATEST HRRR IS NOT DOING
VERY WELL WITH CURRENT ACTIVITY--BUT DOES SHOW POTENTIAL FOR
CONVECTION ALONG AND NORTH OF THIS BOUNDARY IN THE EARLY HOURS OF
MONDAY---CONTINUING POST 1200 UTC IN THE AXIS OF HIGH PW
VALUES---1.75"+ EXPECTED TO PERSIST IN THE VICINITY OF THIS
BOUNDARY.  THIS HEAVY RAINFALL SOLUTION IS ALSO SUPPORTED BY MUCH
OF THE OTHER HI RES GUIDANCE---ALTHOUGH THERE ARE THE USUAL
DIFFERENCES IN DETAILS WITH RESPECT TO PLACEMENT.    WV IMAGERY IS
SHOWING SHORTWAVE ENERGY MOVING EASTWARD FROM CENTRAL TEXAS EARLY
THIS MORNING.   UPPER DIFFLUENCE AHEAD OF THIS SHORTWAVE EXPECTED
TO ENHANCE IN THE VICINITY OF THE OUTFLOW BOUNDARY OVER THE NEXT
FEW HOURS AND CONTINUE INTO THE POST 1200 UTC HOURS.  THIS SHOULD
SUPPORT THE CONTINUATION OF THE ACTIVE CONVECTION IN THE VICINITY
OF THE OUTFLOW BOUNDARY.  ISOLATED RUNOFF ISSUES MAY DEVELOP IN
THE EARLY HOURS OF MONDAY MORNING---CONTINUING AFTER 1200 UTC FROM
POTENTIAL OF SEVERAL ROUNDS OF CONVECTION MOVING FROM NORTHEAST TX
INTO NORTHERN LA.

ORAVEC

ATTN...WFO...FWD...HGX...JAN...LCH...SHV...

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

LAT...LON   32829248 32709174 32609127 32429100 32089107 
            31889119 31189287 31049384 30909492 31119593 
            31819571 31909565 32239481 32789360 32769284