Graphic for MPD #0347

MESOSCALE PRECIPITATION DISCUSSION 0347
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
225 AM EDT TUE JUN 20 2017

AREAS AFFECTED...CNTRL AND NRN NC INTO FAR SERN VA

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

VALID 200625Z - 201100Z

SUMMARY...FLASH FLOODING WILL REMAIN POSSIBLE IN THE SHORT TERM
ACROSS CNTRL TO NRN NC AND INTO FAR SERN VA. RAINFALL RATES 1-2
IN/HR MAY ALLOW FOR AN ADDITIONAL 1-3 INCHES BY 12Z WHERE CELL
TRAINING IS MAXIMIZED.

DISCUSSION...AS OF 06Z...REGIONAL REFLECTIVITY ACROSS NC INTO SERN
VA HAS CONTINUED TO SHOW TRAINING ECHOES OF HEAVY RAIN CONTAINING
AVERAGE RAINFALL RATES OF 1-2 IN/HR...ALTHOUGH LOCALLY HIGHER
RATES HAD BEEN OBSERVED EARLIER TONIGHT. CLOUD TOP TEMPERATURES ON
EXPERIMENTAL GOES 16 INFRARED IMAGERY HAVE LARGELY BEEN WARMING
ACROSS THE MID-ATLANTIC REGION OVER THE PAST 2 HOURS...BUT
OCCASIONAL BURSTS OF COLDER TOPS CONTINUE TO APPEAR OVER THE
REGION. THE LINGERING CONVECTION IS LOCATED BENEATH A STRONGLY
DIFFLUENT JET PATTERN ALOFT AND MUCAPE REMAINS 500-1500
J/KG...DESPITE AN ESTIMATED LOWERING OF ROUGHLY 500-1000 J/KG OVER
THE PAST 3 HOURS ACCORDING TO THE LATEST SPC MESOANALYSIS.

UNIDIRECTIONAL WSWLY FLOW WILL CONTINUE THROUGH THE REMAINDER OF
THE OVERNIGHT ACROSS NC AND SERN VA AHEAD OF A SLOW MOVING COLD
FRONT THAT EXTENDED FROM CNTRL VA INTO WRN NC AT 06Z. THE ONGOING
RAINFALL AXIS IS EXPECTED TO SLOWLY SHIFT SEWD BY 12Z BUT A
LIMITING FACTOR FOR MUCH IN THE WAY OF ADDITIONAL FLASH FLOODING
WILL BE WANING INSTABILITY WITH REDUCTIONS IN MUCAPE OCCURRING
FROM NORTHWEST TO SOUTHEAST. IN ADDITION...ONGOING 850 MB WIND
SPEEDS OF 35-40 KT AT KAKQ AND KRAX...VIA VAD WIND PLOTS...ARE
FORECAST TO WEAKEN TO 30 KT OR LESS BY 12Z AS A POSITIVELY TILTED
MID-UPPER LEVEL SHORTWAVE TROUGH AXIS OVER WV AND VA CONTINUES TO
LIFT NEWD. THIS REDUCTION IN 850 MB WIND SPEEDS WILL LIMIT THE
ABILITY FOR CELLS TO TRAIN GIVEN MEAN STORM MOTIONS SHOULD
CONTINUE AT 30-40 KT. THE COMBINATION OF WEAKENING MUCAPE AND
WEAKENING LOW LEVEL INFLOW THROUGH 12Z IS EXPECTED TO TAPER
ONGOING FLASH FLOODING BY 11Z. UNTIL THEN HOWEVER...ADDITIONAL
FLASH FLOODING WILL STILL BE POSSIBLE IN ONE OR TWO LOCATIONS
BETWEEN CNTRL NC AND FAR SERN VA AS RAINFALL SLOWLY SHIFTS
SOUTHEAST.

OTTO

ATTN...WFO...AKQ...GSP...MHX...RAH...

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

LAT...LON   37227540 36297561 35477768 35117977 35568035
            36017953 36327874 36647782 37087659


Last Updated: 225 AM EDT TUE JUN 20 2017