MESOSCALE PRECIPITATION DISCUSSION 0391
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
500 AM EDT SAT JUN 24 2017

AREAS AFFECTED...SOUTHEAST LA, SOUTHERN MS, AND SOUTHERNMOST AL

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

VALID 240859Z - 241259Z

SUMMARY...A SLOWING LINE OF THUNDERSTORMS IS CLOSING IN ON THE
CENTRAL GULF COAST.  HOURLY RAIN RATES UP TO 1.5", WITH LOCAL
AMOUNTS TO 3", COULD CAUSE ISSUES OVER PARTIALLY SATURATED TO
SATURATED SOILS.

DISCUSSION...THUNDERSTORMS CONTINUE THEIR SOUTHEAST MARCH INTO
SOUTHEAST LA AND SOUTHERN MS.  INFLOW AT 850 HPA IS 15-20 KTS FROM
THE WEST-SOUTHWEST.  PRECIPITABLE WATER VALUES OF 2-2.2" EXIST
HERE PER GPS DATA.  EFFECTIVE BULK SHEAR OF 25 KTS IS ADVERTISED
BY RECENT SPC MESOANALYSES.  MUCAPE VALUES ARE 1000-3000 J/KG.

THE MESOSCALE GUIDANCE, OUTSIDE OF THE 00Z SPC WRF AND 07Z HRRR,
HAS COMPLETELY MISSED OUT ON THIS ACTIVITY OR IS WAY TOO SLOW IN
THEIR FORWARD PROGRESSION.  SHOWERS AND THUNDERSTORMS SHOULD
CONTINUE TO DEVELOP AHEAD OF THE LINE AND MERGE IN, ENHANCING
HOURLY RAIN RATES FROM TIME TO TIME.  HOURLY RAIN RATES UP TO 1.5"
ARE EXPECTED, WITH LOCAL AMOUNTS TO 3".  CONSIDERING RAINFALL OVER
THE PAST FEW DAYS, SOILS ARE PARTIALLY TO COMPLETELY SATURATED. 
THIS DEGREE OF RAINFALL COULD BE PROBLEMATIC.

ROTH

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

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

LAT...LON   31278890 30708810 30068833 29698943 29479057
            29599118 30009141 30479131 30659078 31228949