MESOSCALE PRECIPITATION DISCUSSION 0220
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
831 PM EDT MON MAY 28 2018

AREAS AFFECTED...SOUTH CENTRAL AL...EXT NORTHWEST FL PANHANDLE

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

VALID 290030Z - 290630Z

SUMMARY...FLASH FLOODING RISK REDUCING IN FAVOR OF PROLONGED
INUNDATION FLOODING NEAR THE CENTER OF STS ALBERTO AS IT LIFTS
NORTH IN AL.

DISCUSSION...RADAR/GOES-16 AND SURFACE OBS SHOWS SUB-TROPICAL
STORM ALBERTO IS CURRENTLY IN WALTON COUNTY FL LIFTING NORTH WITH
A SOLID SHIELD OF WARMING INNER CORE CONVECTION TO THE
NORTH...WITH OCCASIONAL VERY SMALL OVERSHOOTING TOPS POPPING
THROUGH THE CANOPY.

LACK OF INCREASED HEATING AND LOSS OF WARM MOISTURE SOURCE OF THE
GULF HAS LED TO AVAILABLE INSTABILITY TO BE EXHAUSTED VERY NEAR
THE INNER CORE AND ALONG THE NORTHERN AND WESTERN NEAR INNER BAND.
 THIS HAS LIMITED AND WILL CONTINUE TO LIMIT VERTICAL CONVECTIVE
GROWTH...HOWEVER STRONG MST CONVERGENCE AND ISNETROPIC ASCENT WITH
VWP VALUES SHOWING 40-45 KTS THROUGH BOUNDARY LAYER TO 7H DIRECTED
OVER THE RESIDUAL EFFECTIVE FRONTAL STRUCTURE OVER THE NNE
QUADRANT OF THE CYCLONE WILL REMAIN STRONG AND GIVEN TRACK WILL
ALLOW FOR NEARLY CONSISTENT MODERATE TROPICAL (SMALL AND NUMEROUS
DROPLETS) SHOWERS.  SURFACE TDS TO IN THE LOW 70S AID FOR NEAR
CORE TPWS OVER 2.25" WITH THIS SLOWER BROAD ASCENT WILL STILL BE
CAPABLE OF .75"/HR RATES WITH NEARLY ZERO SUB-CLOUD EVAPORATIVE
LOSS.  OCCASIONAL HOURLY TOTALS AOA 1" ARE POSSIBLE NEAR INCREASED
CONVERGENCE BANDS SUCH AS ONE IN PIKE TO CRENSHAW COUNTY CURRENT. 
 ALL IN ALL THIS SUGGESTS 3-4" TOTALS THROUGH THE NEXT 6 HOURS ARE
PROBABLE FROM COVINGTON TOWARD DALLAS/LOWNDES COUNTY. FAIRLY
STRONG HI-RES AGREEMENT TO THIS RANGE AND PLACEMENT PROVIDES SOLID
CONFIDENCE IN THIS EVOLUTION.  BUT IN A TECHNICAL SENSE THIS WOULD
NEAR OR BARELY EXCEED EVEN 6HR FFG HOWEVER SHEAR INUNDATION IS
LIKELY TO LEAD TO FLOODING...SO FOR THIS DISCUSSION FF WILL BE
CONSIDERED POSSIBLE ESPECIALLY IN URBAN SETTINGS NEAR MGM.

GALLINA

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

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

LAT...LON   32938666 32808605 31698573 31008585 30728637
            30718663 30878696 31248724 31608738 32078744
            32278739 32588727