MESOSCALE PRECIPITATION DISCUSSION 0234
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
929 AM EDT FRI MAY 19 2017

AREAS AFFECTED......NORTHERN TN TO SOUTHEAST KY...SOUTHERN WV AND
SOUTHWEST VA...

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

VALID 191329Z - 191929Z

SUMMARY...BANDS OF SHOWERS AND STORMS REFORMING OVER A SIMILAR
AXIS RESULT IN POTENTIAL FOR ISOLATED HEAVY RAIN AND FLASH
FLOODING.

DISCUSSION...CLUSTER OF SHOWERS AND STORMS CONTINUE TO FORM WITHIN
CONFLUENT LOW LEVEL FLOW WITH THE 12Z UPPER AIR OBS SHOWING AN
ENHANCED MOISTURE AXIS WITH THE NASHVILLE 12Z SOUNDING SHOWING 1.6
INCHES OF PRECIPITABLE WATER FEEDING INTO THE AREA OF
SHOWERS/STORMS. 

THE SPC MESOANALYSIS SHOWS SHOWERS/STORMS FORMING WITHIN AN AREA
DEFINED BY A 300 MB DIVERGENCE MAXIMA AND BOUNDARY LAYER MOISTURE
CONVERGENCE.  WITH THE AFOREMENTIONED HIGHER MOISTURE AVAILABLE
AND 850-700 MB MOISTURE TRANSPORT CONTINUING OVER THE NEXT SEVERAL
HOURS...ADDITIONAL SHOWERS AND STORMS ARE EXPECTED.  WHILE THE
MODELS ARE NOT SHOWING PARTICULARLY HIGH RAINFALL SUCH AS THE RAP
INDICATING 1.5-2 INCHES OF RAIN WITHIN THE REGION...LOCAL TRAINING
IS LIKELY TO LEAD TO HIGHER AMOUNTS. 

FLOODING HAS BEEN REPORTED IN ACTIVITY IN NORTH CENTRAL TN WITH
ADDITIONAL LOCAL FLOODING POSSIBLE HERE AND DOWNSTREAM INTO
SOUTHEAST KY...SOUTHERN WV...AND SOUTHWEST VA AS THE 850 MB JET
AND PRECIPITABLE WATER AXIS FUELS MORE SHOWER/STORM DEVELOP WITHIN
THE LOW LEVEL CONVERGENCE AXIS IN THE AREA.

ADDITIONAL CLUSTERS OF 1-3 INCHES OF RAIN ARE EXPECTED AND JACKSON
KY RADAR ALREADY SHOWS AREAS OF 1-3 INCHES OF RAIN THAT HAS
OCCURRED...SO WHERE THESE ADDITIONAL RAINS REPEAT OVER THESE
AREAS...ADDITIONAL FLOODING PROBLEMS MAY DEVELOP.
THE HEAVIEST OF THE MODEL GUIDANCE IS THE CANADIAN REGIONAL GEM
WITH 2-3 INCHES IN PORTIONS OF SOUTHEAST KY. THE 11Z VERSION OF
THE HIGH RES RAPID REFRESH INDICATES AN ISOLATED MAX OF 3 INCHES
IN SOUTH CENTRAL KY NORTH OF THE TN BORDER.  IN SPITE OF THE LOW
QPF IN THE RAP...PERSISTING 300 MB DIVERGENCE IN THE AXIS OF THE
LOW LEVEL JET AND MOISTURE PLUME LOOKS FAVORABLE FOR CONTINUING
SHOWERS/STORMS. 

PETERSEN



ATTN...WFO...JKL...LMK...MRX...OHX...PAH...RLX...RNK...

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

LAT...LON   38098093 37958068 37498085 37168154 36938235
            36818314 36658378 36398516 36348616 36338727
            36748727 37098664 37698455 38048274