MESOSCALE PRECIPITATION DISCUSSION 0224
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
206 AM EDT SAT MAY 21 2016
 
AREAS AFFECTED...COASTAL NORTH CAROLINA 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 210605Z - 211105Z
 
SUMMARY...RAINFALL RATES UP TO 2-3"/HR WITH SOME POTENTIAL
TRAINING MAY PRODUCE LOCALIZED FF CONCERNS.

DISCUSSION...WV SHOWS APPROACH OF S/W TROF TO SUPPORT SURFACE
PRESSURE FALLS AT THE APEX FRONTAL ZONE ALONG THE SC COAST NEARING
CAPE FEAR THEN TURNING ESE OUT TO SEA WITH STRONG 20-30 KTS
SURFACE FLOW NORTH OF THE FRONT.  RADAR MOSAIC INDICATES MODERATE
BANDING FEATURES ACROSS THE OUTER BANKS...PRECEDING THE STRONGER
CONVECTIVE CELLS NEARING THE SW NC COAST...ALONG THE AXIS OF
MAXIMIZED AND VERY STRONG SURFACE MOISTURE CONVERGENCE.  THIS
STRONG SFC MST CONVERGENCE WITH NEARING 2" TPWS WILL PRODUCE
EFFICIENT RAINFALL PRODUCING UPDRAFTS CAPABLE OF RATES IN THE
2-3"/HR RANGE POSSIBLY HIGHER IF COASTAL FRICTIONAL CONVERGENCE
HELPS TO ANCHOR THE UPDRAFTS.  RADAR MOSAIC SHOWS THAT THESE CELLS
HAVE ALSO HAVE AN ORIENTATION FAVORABLE TO TRAINING AS THE SURFACE
WAVE DEVELOPS INTO E NC AS IT TRACKS NNE.  MULTIPLE HI-RES CAMS
ARE SUPPORTIVE OF THE TRAINING ELEMENT WITH SOME INCREASED
COVERAGE ALONG THE LINE AS WELL...LEADING TO THE POTENTIAL FOR
3-5".  

THE LIMITING QUESTION IS WHETHER STRONG CONTINUED ONSHORE FLOW AND
INSTABILITY AXIS MAY KEEP REDEVELOPMENT WITHIN THE SOUNDS OR EVEN
EAST OF THE OUTER BANKS...THOUGH RECENT TRENDS WOULD SUGGEST
OTHERWISE IT IS STILL NOT OUT OF THE REALM OF POSSIBILITY.  OTHER
LIMITING FACTORS INCLUDE THE NATURE OF SANDY/SWAMPY AREAS THOUGH
WITH ONSHORE FLOW OUTFLOW TO THE SOUNDS MAY BE MITIGATED ALLOWING
FOR BACK-LOADING OF THE RIVERS/OUTLETS FOR ADDITIONAL FLOODING
CONCERNS.  STILL GIVEN HIGH RATES/EFFICIENCY ISOLATED FF THREAT IS
POSSIBLE.


GALLINA

ATTN...WFO...AKQ...ILM...MHX...

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

LAT...LON   36197632 36017545 35407544 34857602 34587645 
            34307709 34267766 34387790 34957778 35837706