Flash Flood Guidance
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000
AWUS01 KWNH 301732
FFGMPD
NCZ000-SCZ000-302330-

MESOSCALE PRECIPITATION DISCUSSION 0270
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
131 PM EDT MON MAY 30 2016

AREAS AFFECTED...E SOUTH CAROLINA...S NORTH CAROLINA

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

VALID 301730Z - 302330Z

SUMMARY...SLOW MOVING CONVECTION ALONG CONVERGENCE BOUNDARY AND
NEAR CENTER OF POST-TROPICAL BONNIE.

DISCUSSION...WELL DEFINED SURFACE MST BOUNDARY/DEFORMATION ZONE
EXIST FROM SE OF SSC-FLO-POB-JNX (I-95 CORRIDOR) JUST N OF THE
CENTER OF POST-TROPICAL CYCLONE BONNIE IN CENTRAL WILLIAMSBURG
COUNTY.   SLOW EASTWARD DRIFT IS FORECAST AND SO THE BOUNDARY
SHOULD REMAIN STATIONARY FOR CONTINUED FOCUS OF CONVECTIVE
DEVELOPMENT. THIS IS PARTICULARLY A THREAT WHERE ONSHORE
CONVECTIVE BANDS PERPENDICULARLY INTERSECT THE BOUNDARY MAINLY
WHERE INSOLATION HAS SUPPORTED INCREASED INSTABILITY WITH MLCAPES
GREATER THAN 1000 J/KG AND TPWS IN THE 1.75-2" RANGE. GIVEN
PROFILES ARE ON AVERAGE 6C/KM AND STRONG MST CONVERGENCE/FLUX...
CELL EFFICIENCY SHOULD BE QUITE HIGH WITH RATES OVER 2"/HR
LIKELY...PROBABLY HIGHER IF CELLS MERGE/BACKBUILD ALONG THE
ONSHORE BANDS INTERSECTING TO THE BOUNDARY.  HI-RES CAMS ARE
SUPPORTIVE OF THE EVOLUTION AND AXIS OF PRECIPITATION BUT DIFFER
WITH RESPECT TO TOTALS ALONG THE BOUNDARY THINKING MORE IN LINE OF
THE 12Z ARW/NMMB IN THE 2-4" RANGE.

FURTHER SOUTH NEAR THE LOW...CONVECTION WILL BE MORE LIMITED DUE
TO LACK OF INSTABILITY THOUGH THERE WILL BE ENOUGH FOR SOME
DEVELOPMENT AND EFFICIENT RAINFALL PRODUCTION WITH RATES UP TO
1.5"/HR. HOWEVER CELL MOTIONS WILL BE ZERO OR NEARLY SUCH TO
SUPPORT SOME ISOLATED TOTALS CAPABLE OF NEARING FFG VALUES FOR AN
ISOLATED FLASH FLOOD THREAT HERE AS WELL.

GALLINA

...PLEASE SEE WWW.WPC.NCEP.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...CAE...CHS...ILM...MHX...RAH...

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

LAT...LON   36027817 35347789 34667730 34307781 33937804
            33847856 33507899 33207909 33077924 32997970
            33268028 34058041 34678013 35377951 35837894



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