MESOSCALE PRECIPITATION DISCUSSION 286
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
140 PM EDT TUE MAY 30 2017

AREAS AFFECTED...SOUTHEAST LOUISIANA AND SOUTHERN MISSISSIPPI

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

VALID 301739Z - 302159Z

SUMMARY...THUNDERSTORMS PRODUCING HEAVY RAINFALL RATES ARE
EXPECTED TO CONTINUE ACROSS SOUTHERN LOUISIANA AND EVENTUALLY
EXTREME SOUTHERN MISSISSIPPI THROUGH THE EARLY TO MID AFTERNOON
HOURS.  FLASH FLOODING REMAINS POSSIBLE WITH THE MOST PERSISTENT
CONVECTION.

DESCRIPTION...REGIONAL RADARS INDICATE SLOW MOVING THUNDERSTORMS
PRODUCING RAINFALL RATES OF 2-3 INCHES PER HOUR MOVING INLAND FROM
THE NORTHERN GULF OF MEXICO.  THIS CONVECTION IS FORECAST TO
SLOWLY MOVE EASTWARD OVER SOUTHEAST LOUISIANA THROUGH THE
AFTERNOON HOURS.  THE HEAVIEST RAINFALL RATES AND FLASH FLOOD
POTENTIAL IS LIKELY SOUTH OF INTERSTATE 12.  THE STATIONARY
FRONTAL BOUNDARY NEAR THE COAST WILL PROVIDE A LIFTING MECHANISM
AND THUS ENHANCED MOISTURE CONVERGENCE. 

SURFACE DEW POINTS ARE IN THE MID TO UPPER 70S SOUTH OF THIS
BOUNDARY, WITH THE LATEST SPC MESOANALYSIS INDICATING PWS OF 1.8
TO 2.1 INCHES.  THE LATEST RAP MODEL SHOWS PWS REMAINING NEAR 2
INCHES AS MOISTURE POOLS ALONG AND SOUTH OF THIS FRONT.  THE RAP
AND SPC MESOANALYSIS ALSO SHOW SURFACE BASED CAPES OF 2000-3000
J/KG OVER THE NEXT FEW HOURS NEAR AND JUST INLAND FROM THE COAST. 
THE 16Z HRRR SHOWS ADDITIONAL RAINFALL ACCUMULATIONS OF LOCALLY 2
TO 4 INCHES WITHIN THE HIGHLIGHTED AREA BY 5 PM LOCAL TIME, WITH
ADDITIONAL HEAVY RAINFALL POSSIBLE DURING THE EVENING HOURS. 

HAMRICK

ATTN...WFO...JAN...LCH...LIX...MOB...

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

LAT...LON   31018933 31008878 30858844 30518837 30208841
            29858873 29568885 28918906 28949010 28989109
            29369171 29479235 29659246 30059239 30369220
            30709161 30859115 30959048 31008987