MESOSCALE PRECIPITATION DISCUSSION 0288
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
539 AM EDT THU JUN 01 2017

AREAS AFFECTED...EASTERN TX...SOUTHERN LA

CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE

VALID 010938Z - 011500Z

SUMMARY...SEVERAL CLUSTERS OF SLOW-MOVING THUNDERSTORMS WILL
LIKELY RESULT IN SOME VERY HEAVY RAINFALL TOTALS. SOME FLASH
FLOODING AND/OR RUNOFF PROBLEMS WILL BE POSSIBLE.

DISCUSSION...RADAR IMAGERY HAS BEEN SHOWING A GRADUAL INCREASE IN
THE COVERAGE OF GENERALLY DISORGANIZED CLUSTERS OF SHOWERS AND
THUNDERSTORMS OVER SOUTHEAST TX AND SOUTHERN LA. HOWEVER...SOME OF
THE ACTIVITY IS VERY SLOW MOVING AND IS EMBEDDED WITHIN A VERY
MOIST COLUMN WITH PWATS OF 1.8 TO 2 INCHES AS PER GPS-DERIVED
DATA. SUPPORT FOR THE CONVECTION THIS MORNING APPEARS TO BE HIGHLY
TIED INTO THE STRONGLY DIFFLUENT UPPER AIR PATTERN OVER THE
WESTERN/CENTRAL GULF COAST REGION WITH THE APPROACH OF AN UPSTREAM
SHORTWAVE OVER SOUTHEAST TX AND ALSO PLACEMENT GENERALLY WITHIN
THE RIGHT-ENTRANCE REGION OF A WEAK SOUTHERN STREAM 250 MB JET
MAX. THE AIRMASS IS QUITE MOIST AND AT LEAST MODESTLY UNSTABLE.
SOME WEAK LOW LEVEL SPEED CONVERGENCE IS NOTED AS WELL WHICH
APPEARS TO BE AIDING THE CONVECTIVE EXPANSION OVER THE LAST COUPLE
OF HOURS.

THE LAST FEW RUNS OF THE HRRR HAVE BEEN QUITE AGGRESSIVE IN
BRINGING HEAVY RAINFALL THIS MORNING TO PARTS OF EASTERN TX AND
SOUTHERN LA...WITH FORECASTS OF AS MUCH AS 3 TO 5 INCHES THROUGH
MID-MORNING. THESE HIGHER TOTALS ARE LIKELY TO BE RATHER
LOCALIZED...BUT SOME RUNOFF PROBLEMS AND/OR FLASH FLOODING WILL BE
POSSIBLE.

ORRISON

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

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

LAT...LON   32269541 31879421 31359296 30969164 30769129
            30379105 29899087 29399122 29529184 29519229
            29629272 29749317 29659379 29629426 29829471
            30249479 30679500 31209586 31899601