MESOSCALE PRECIPITATION DISCUSSION 0211
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
245 AM EDT MON MAY 28 2018

AREAS AFFECTED...EASTERN FLORIDA PANHANDLE...

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

VALID 280645Z - 281230Z

SUMMARY...TRAINING ONSHORE BAND OF STS ALBERTO ENHANCED BY DIURNAL
CONVECTIVE MAXIMA AND CONVERGENCE POSE PSBL FLASH FLOODING RISK
EVEN WITH HIGH FFG IN THE REGION.

DISCUSSION...RECENT GOES-16 10.3UM IR AND TLH RADAR SHOWS BANDED
CONVECTIVE DEVELOPMENT WITHIN APALACHEE BAY EXPANDING IN BOTH
DIRECTIONS TOWARD WAKULLA COUNTY AS WELL AS HUGGING THE COAST
TOWARD CEDAR KEY. THIS IS LIKELY DIRECTED BY LAND BREEZE COMING
OFFSHORE AND SOUTHERLY FLOW ON THE EASTERN SIDE OF ALBERTO. RAP
ANALYSIS SHOWS THIS SOLID SFC MST CONVERGENCE COINCIDENT WITH
SBCAPES AOA 2000 J/KG SUPPORTING ADDITIONAL DEVELOPMENT.  GIVEN
WESTWARD WOBBLE OF ALBERTO EXPECTED BEFORE NORTHWARD TRACK...THIS
BAND HAS THE POTENTIAL TO BE FAIRLY STATIC WITH UPSTREAM
DEVELOPMENT.  WHILE THE CONVECTION IS ON THE EASTERN PERIPHERY OF
THE INNER CORE/MOISTURE CORE PER CIRA LPW ANALYSIS...MOISTURE IS
AMPLE FOR SOLID 2"/HR RATES.  GIVEN BULK SHEAR VALUES OF 25-30KT
AND PROPAGATION VECTORS NEAR ZERO OR EVEN UPWIND IN THE BAND
SUGGEST CONTINUED TRAINING IS LIKELY FOR THE NEXT FEW HOURS.  AS
SUCH 4-6" OF RAIN IS PROBABLE AND WOULD BE VERY NEAR FFG VALUES IN
THE AREA.  WHILE LIKELY ENOUGH TIME TO PASS GIVEN OUTFLOW TO THE
SEA...THE AREA WAS RECENT AFFECTED BY A 10" RAINFALL THAT MAY
LOWER THRESHOLDS EVEN BY A FRACTION.  ALL CONSIDERED FLASH
FLOODING OR MORE LIKELY QUICK INUNDATION FLOODING IS POSSIBLE OVER
THE NEXT 5-6 HOURS.

INNER CORE BAND IS CLIPPING FAR SOUTHERN TIP OF GULF AND FRANKLIN
COUNTY...LACK OF INSTABILITY HERE HAS LIMITED VERTICAL GROWTH OF
RAIN PRODUCTION LAYER TO HAVE HIGH RATES.  HOWEVER...IT IS
POSSIBLE WITH ALBERTO'S WESTWARD DRIFT THE UPSTREAM BAND MAY ANGLE
WEST ENOUGH TO POSE AT LEAST A LOW CHANCE TO BE ENCOMPASSED BY THE
MPD AREA OF CONCERN.

GALLINA

ATTN...WFO...TAE...

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

LAT...LON   30658506 30488442 30378418 30208390 29828356
            29868383 29848395 29878423 29628484 29588513
            29928549 30108552 30298503