MESOSCALE PRECIPITATION DISCUSSION 0686
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
123 AM EDT MON AUG 14 2017

AREAS AFFECTED...WESTERN NC...FAR NORTHWEST SC

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

VALID 140515Z - 140915Z

SUMMARY...SLOW-MOVING HEAVY SHOWERS ARE EXPECTED TO CONTINUE OVER
THE NEXT FEW HOURS. SOME ADDITIONAL FLASH FLOODING IS POSSIBLE IN
THE SHORT TERM...WITH CONDITIONS IMPROVING TOWARD DAWN.

DISCUSSION...A RELATIVELY SMALL BUT SLOW-MOVING AND ELONGATED AXIS
OF HEAVY SHOWERS IS NOTED OVER WESTERN NC STRETCHING FROM NEAR
RUTHERFORDTON NORTHWARD UP TO NEAR NORTH WILKESBORO. THE
CONVECTION HAS BEEN FOCUSING IN AREA WHERE THERE IS A RELATIVE
MAXIMA IN SURFACE MOISTURE CONVERGENCE OWING TO SOME LOW LEVEL
NORTHEASTERLY FLOW BUMPING UP AGAINST EASTERLY AND SOUTHEAST FLOW
AROUND THE BACK SIDE OF A FRONTAL ZONE AND WEAK AREA OF LOW
PRESSURE. THE ACTIVITY IS ALSO FOCUSING WITHIN AN INSTABILITY
GRADIENT.

THE LATEST HRRR GUIDANCE CONTINUES TO FOCUS SOME ADDITIONAL HEAVY
RAINFALL ACROSS THE MPD THREAT AREA OVER THE NEXT FEW
HOURS...BEFORE THEN WEAKENING AS THE INSTABILITY WANES AND THE
SURFACE CONVERGENCE WEAKENS AS WELL. HOWEVER...THE HRRR HAS BEEN
ADVERTISING AS MUCH AS 3 TO 5 INCHES OF A SMALL SCALE...AND
ALREADY THERE HAVE BEEN DUAL-POL ESTIMATES OF OVER 3 INCHES
LOCALLY. SOME ADDITIONAL FLASH FLOODING CONCERNS WILL EXIST FOR A
FEW MORE HOURS...BUT CONDITIONS SHOULD IMPROVE BY 09Z.

ORRISON

ATTN...WFO...GSP...RAH...RNK...

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

LAT...LON   36488061 36288023 35398077 34918165 34878225
            35238258 35778205 36248149 36468080