MESOSCALE PRECIPITATION DISCUSSION 0310
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
130 PM EDT SAT JUN 04 2016
 
AREAS AFFECTED...CENTRAL/EASTERN TN...EASTERN KY....SOUTHWEST
VA...CENTRAL/SOUTHERN WV...SOUTHEAST OH 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY 
 
VALID 041720Z - 042330Z
 
SUMMARY...VERY HEAVY SHOWERS AND THUNDERSTORMS ARE EXPECTED THIS
AFTERNOON WITH POCKETS OF CELL-MERGERS AND SOME TRAINING. FLASH
FLOODING IS LIKELY AS A RESULT.

DISCUSSION...VIS SATELLITE IMAGERY SHOWS AN EXPANSIVE AREA OF
INCREASINGLY AGITATED CU/TCU NEAR AND WEST OF THE CENTRAL
APPALACHIANS AND DOWN THROUGH THE CUMBERLAND PLATEAU AND ADJACENT
AREAS OF THE TN VALLEY. ALREADY SEEING SOME RAPIDLY COOLING
CONVECTIVE TOPS OVER PARTS OF SOUTHERN KY AND NORTHERN TN...WITH A
SEPARATE CLUSTER OF CONVECTION IN SOUTHWEST WV.

AS COORDINATED WITH NESDIS/SAB...THE 12Z RAOB OUT OF BNA DEPICTED
UNIDIRECTIONAL FLOW IN THE CLOUD BEARING LAYER AND PWATS NEAR 1.75
INCHES. THESE VALUES ARE 1 TO 2 STD ABOVE NORMAL. A SW/NE MOISTURE
AXIS WAS SEEN POOLED WEST OF THE APPALACHIAN MOUNTAINS...WHICH IS
1 TO 2 STD DEV ABOVE NORMAL...AND COINCIDING WITH 2000 J/KG OF
MUCAPE IN THE AREA OF CONCERN. 

CONVECTION WILL EXPAND IN COVERAGE WITH THE AID OF ADDITIONAL
DIABATIC HEATING THROUGH THE AFTERNOON AND ALSO THE AID OF
OROGRAPHICS AT LEAST LOCALLY AND THIS IS SUPPORTED BY A CONSENSUS
OF THE HIRES GUIDANCE.

FFG VALUES ARE LOCALLY RATHER LOW ACROSS THE REGION...AND WITH THE
DEEPER WARM/MOISTURE PROFILES SUGGESTING HIGHLY EFFICIENT RAINFALL
PRODUCTION AND INTENSE RAINFALL RATES...THERE WILL BE AN ELEVATED
CONCERN FOR FLASH FLOODING. RAINFALL RATES ARE LIKELY TO REACH
BETWEEN 2 TO 2.5 INCHES/HR...BUT WITH THE UNIDIRECTIONAL FLOW
PROMOTING CELL-TRAINING AND INCLUSIVE OF CELL-MERGERS...SEVERAL
INCHES OF RAIN IS POSSIBLE THAT MAY APPROACH 5 INCHES LOCALLY.

ORRISON

ATTN...WFO...GSP...HUN...ILN...JKL...LMK...MRX...OHX...PBZ...
RLX...RNK...

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

LAT...LON   39648061 39097988 37928046 36228257 35098462 
            35248594 36118647 37408572 38888396 39638181