MESOSCALE PRECIPITATION DISCUSSION 0229
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
851 PM EDT TUE MAY 29 2018

AREAS AFFECTED...WESTERN TN...WESTERN KY...EXT SOUTHEAST MO...EXT
SOUTHERN IL...

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

VALID 300050Z - 300700Z

SUMMARY...MODERATE TROPICAL RAINS OF TROPICAL DEPRESSION ALBERTO
TRACKING THROUGH LOCALLY LOWER FFG VALUES KEEPING FLASH FLOODING
POSSIBLE.

DISCUSSION...CANOPY OF TROPICAL DEPRESSION ALBERTO CONTINUES TO
EXPAND WITH SOME RECENT ENHANCED UPDRAFTS/ISENTROPIC ASCENT WITH
INCREASED INSTABILITY WITH A FEW LIGHTNING STRIKES NOTED ALONG THE
TN/KY BORDER.  WIND SHEAR HAS SLACKED A BIT TO ALLOW FOR INCREASED
CLOUD COVERAGE TOWARD THE SOUTH AND ABILITY FOR INCREASED MODERATE
SHOWERS TO WRAP AROUND THE SW QUADRANT.  EVEN WITH THIS RECENT
UPTICK...THE CONVECTIVE ELEMENTS ARE NOT PARTICULARLY WIDE SPREAD
AND ARE SHORT ENOUGH IN DURATION (TYPICALLY IN N AND EASTERN
HEMISPHERES) THAT OVERALL RAIN TOTALS WILL REMAIN BELOW EVEN
LONGER TERM FFG VALUES IN THE REGION.  HOWEVER FURTHER EXPANSION
OF SHOWERS DOWNSTREAM AND ISENTROPIC ASCENT OVER EFFECTIVE LOW
LEVEL BOUNDARY THAT EXTENDS NORTHWARD FROM CENTER IN WAYNE COUNTY,
TN TOWARD UNION AND CRITTENDEN COUNTIES, KY.  SFC TDS IN THE
MID-70S AND NEAR SATURATED PROFILES TO OVER 5H PER 00Z BNA
SOUNDING AND SKINNY SBCAPES TO 2500 J/KG WILL KEEP BROAD
ISENTROPIC ASCENT FOR MODERATE TO HEAVY EFFICIENT TROPICAL SHOWERS
WEST OF THE BOUNDARY.  CONSISTENT RAIN RATES OF .5-.75"/HR AND
CURRENT TRACK OF ALBERTO ALONG THE EFFECTIVE BOUNDARY WILL
CONTINUE TO PROVIDE HOURS OF THIS MODERATE RAIN WITH TOTALS OF
2-3" LIKELY OVER THE NEXT 6HRS.  THIS WILL BE FALLING THROUGH THE
LOWER TN AND OHIO RIVER VALLEY/MS RIVER CONFLUENCE ZONE WHERE FFG
VALUES ARE A LOCAL MINIMA AND 6HR VALUES OF 2.5-3.5" REMAIN AOA
EXCEEDANCE BY THIS PROLONGED RAINFALL.  WHILE THIS FLOODING WILL
LIKELY BE MORE OF INUNDATION WITH LONGER TIME FRAMES...FLASH
FLOODING IS CONSIDERED POSSIBLE. 

GALLINA

ATTN...WFO...MEG...OHX...PAH...

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

LAT...LON   37488863 37298821 37028810 36418782 35868751
            35138794 35058863 35358932 36108950 36758959
            37188952 37418905