MESOSCALE PRECIPITATION DISCUSSION 0226
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
255 PM EDT TUE MAY 29 2018

AREAS AFFECTED......NORTHWEST ALABAMA TO WESTERN TN AND NORTHEAST
MS...

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

VALID 291854Z - 300054Z


SUMMARY...HEAVY SHOWERS AND PERIODS OF RAIN WILL PRODUCE 1-3
INCHES OF RAIN ACROSS NORTHWEST AL AND WESTERN TN TO NORTHEAST MS
THROUGH 01Z...

RADAR AND SATELLITE DATA SHOW SUBTROPICAL DEPRESSION ALBERTO
MOVING NORTH NORTHWEST ACROSS NORTHERN ALABAMA.  SURFACE DATA
INDICATES 1-3 INCHES OF RAIN FELL IN THE 6 HOURS BETWEEN 12Z-18Z
AND SIMILAR
AMOUNTS ARE EXPECTED AGAIN THROUGH 01Z. FLASH FLOODING IS POSSIBLE.

DISCUSSION...
AN AREA OF RAIN CONTINUES DUE TO THE COMBINED IMPACTS OF WELL
DEFINED BOUNDARY LAYER MOISTURE CONVERGENCE AND MOISTURE FLUXES
ROTATING AROUND THE CIRCULATION OF THE DEPRESSION...ALONG WITH A
WELL DEFINED 850-700 MB DEFORMATION ZONE ON THE WESTERN FLANK OF
THE CIRCULATION.

WITH THESE FEATURES FORECAST TO PERSIST OVER THE NEXT SEVERAL
HOURS WITH 850-700 MB THETA-E ADVECTION MAXIMIZING ALONG THE PATH
OF THE CIRCULATION AS IT MOVES NORTH NORTHWEST FROM NORTHERN AL
ACROSS INTO WESTERN TN. THE RAINS WILL MOVE NORTH NORTHWEST IN
TANDEM WITH THE CIRCULATION.

THE 06Z NAM/12Z GFS/16-17Z HIGH RES RAPID REFRESH MODELS AND THE
HURRICANE WRF/HMON TROPICAL CYCLONE MODELS FORECAST AMOUNTS IN THE
1-3 INCH RANGE AND CLUSTER FAIRLY WELL...WHICH IS EXPECTED DUE TO
THE LONG LASTING AND WELL DEFINED CIRCULATION.
THE 12Z NAM HIGHER MAXIMA NEAR 4 INCHES ...WHICH IS UNLIKELY OWING
TO THE RELATIVE MINIMUM OF CONVECTIVE INSTABILITY AND HISTORY OF
LOWER AMOUNTS.

PETERSEN   

ATTN...WFO...BMX...HUN...MEG...OHX...

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

LAT...LON   36398735 35388683 34438724 34018786 34478844
            35178867 35798872 36288817