MESOSCALE PRECIPITATION DISCUSSION 347
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
415 PM EDT THU JUN 21 2018

AREAS AFFECTED...EASTERN KY...SOUTHEAST OH...CENTRAL WV...WESTERN
VA

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

VALID 212015Z - 220115Z

SUMMARY...CONVECTION IS EXPECTED TO INCREASE IN COVERAGE LATE THIS
AFTERNOON AND INTO THE EVENING IN THE VICINITY OF A
QUASI-STATIONARY FRONT.  SOME AREAS WILL LIKELY HAVE REPEATED
ROUNDS OF STORMS THAT COULD LEAD TO LOCALIZED FLASH FLOODING.

DISCUSSION...A SUSTAINED INFLUX OF DEEP MOISTURE INTERSECTING A
STALLED FRONTAL BOUNDARY IS SUPPORTING THE DEVELOPMENT OF NUMEROUS
SHOWERS AND STORMS THIS AFTERNOON.  GOES 16 INFRARED SATELLITE
IMAGERY IS SHOWING EXPANDING CLOUD TOP COOLING THAT IS INDICATIVE
OF STRONGER UPDRAFTS WITH THE CONVECTION.  THE LATEST RAP ANALYSIS
IS INDICATING A CORRIDOR OF 1.9 TO 2.2 INCH PWS EXTENDING TO THE
INTERSTATE 64 CORRIDOR, WHICH IS PLENTY TO FUEL HEAVY DOWNPOURS
WITH THE SLOW MOVING STORMS.  THE 12Z ROANOKE RAOB INDICATED
NEARLY UNIDIRECTIONAL WINDS THROUGH MUCH OF THE LOWER TO MIDDLE
TROPOSPHERE WHICH SUPPORTS SOME BACKBUILDING POTENTIAL.  A MODEST
SHORTWAVE TROUGH AT MID LEVELS OVER THE CENTRAL APPALACHIANS IS
ALSO HELPING PROMOTE ASCENT OVER THE REGION. 

THE LATEST HIGH RES GUIDANCE CONTINUES TO BE CONSISTENT IN
DEPICTING SCATTERED 2 TO 4 INCH RAINFALL AMOUNTS THROUGH 9 PM
LOCAL TIME, ESPECIALLY ACROSS CENTRAL WEST VIRGINIA AND OVER THE
MOUNTAINOUS AREAS OF WEST-CENTRAL VIRGINIA.  FLASH FLOOD GUIDANCE
IS LOWER ACROSS THE SHENANDOAH VALLEY AND INTO THE NORTHERN HALF
OF VIRGINIA OWING TO HEAVY RAINFALL YESTERDAY.  LOCALIZED FLASH
FLOODING IS POSSIBLE, ESPECIALLY OVER MORE MOUNTAINOUS TERRAIN.

D. HAMRICK

ATTN...WFO...AKQ...ILN...JKL...LWX...PBZ...RLX...RNK...

ATTN...RFC...MARFC...OHRFC...SERFC...

LAT...LON   39878268 39788128 39247968 38567821 38197738
            37657706 36727762 36717942 37238084 37638204
            37958312 38198368 38798384 39428352