MESOSCALE PRECIPITATION DISCUSSION 0359
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
137 AM EDT THU JUN 22 2017

AREAS AFFECTED...SOUTHERN AL & THE WESTERN FL PANHANDLE

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

VALID 220536Z - 221136Z

SUMMARY...THUNDERSTORMS ARE EXPECTED TO INVADE THE AREA FROM THE
GULF OF MEXICO OVER THE NEXT SEVERAL HOURS.  HOURLY RAIN RATES UP
TO 2", WITH LOCAL AMOUNTS TO 4", ARE EXPECTED.

DISCUSSION...A SHORTWAVE IS APPARENT ON WATER VAPOR IMAGERY NEAR
THE BACKSIDE OF THE WARM CONVEYOR BELT CIRCULATION AND AHEAD OF
THE DRY SLOT ASSOCIATED WITH T.S. CINDY.  A CONVERGENCE
ZONE/EFFECTIVE STATIONARY FRONT ACTS AS THE BARRIER TO 1000-2000
J/KG OF MLCAPE VALUES.  TO ITS SOUTHEAST, THUNDERSTORMS IN THE
GULF OF MEXICO ARE MOVING TOWARDS THE MPD AREA.  PRECIPITABLE
WATER VALUES OF 2.25-2.5" EXIST IN THIS REGION.  INFLOW AT 850 HPA
IS SLIGHTLY CONVERGENT AT 30-40 KTS.  BULK SHEAR IN THE REGION IS
CLOSER TO 25 KTS, WHICH COMBINED WITH THE FAIRLY UNIDIRECTIONAL
SOUTHERLY FLOW WITH HEIGHT UP TO 330 HPA SHOULD SUPPORT LINEAR
BANDS.

THE 00Z MESOSCALE GUIDANCE IS GENERALLY ON THE SAME PAGE IN THIS
AREA; THE OLDER 12Z MESOSCALE GUIDANCE APPEARS TO BE DOING AN
EXCEPTIONAL JOB IN DEPICTING THE CONVECTIVE UPTICK EXPECTED BEYOND
06Z.  A SHORTWAVE MOVING NORTH FROM THE GULF SHOULD CAUSE RENEWED
THUNDERSTORM ACTIVITY OVER THIS AREA WITHIN THE NEXT HOUR OR TWO,
WHICH IS EXPECTED TO PERSIST PAST SUNRISE.  THERE IS A STRONG
SIGNAL FOR LOCAL AMOUNTS OF 4" IN THIS AREA, THOUGH ITS LOCATION
VARIES; BELIEVE A COMPROMISE OF THE MESOSCALE GUIDANCE IS
PREFERRED.  WHILE RAIN RATES HAVE ONLY OCCASIONALLY BREACHED
1"/HOUR AS OF LATE, THE NEW ACTIVITY COULD CAUSE HOURLY RAIN RATES
TO RETURN TO 2".  SOILS ARE SATURATED FROM RECENT 3-7" RAINS, SO
FLASH FLOODING IS A CONCERN.

ROTH

ATTN...WFO...BMX...MOB...TAE...

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

LAT...LON   32618744 32298617 30228559 30228619 30288717
            30248740 30198820 30318832 30928827 32148814