MESOSCALE PRECIPITATION DISCUSSION 0510
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
229 PM EDT SUN JUL 22 2018

AREAS AFFECTED...SOUTHEAST VA...NORTHEAST NC...

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

VALID 221830Z - 230000Z

SUMMARY...INCREASING CONVECTION WITH TRAINING/REDEVELOPMENT LIKELY
AND RAIN RATES UP TO 2"/HR POSE POSSIBLE FLASH FLOODING.

DISCUSSION...STRONG HEATING BOUNDARY EXISTS ACROSS NORTHEASTERN NC
WITH TEMPS RISING INTO THE LOW 90S ALONG THE COAST BUT LIMITED TO
UPPER 70S ACROSS NORTH CENTRAL NC WHERE CLOUD COVER FROM THE
EXITING MCV REDUCED INSOLATION.  THIS BOUNDARY WAS WELL DEFINED IN
THE EARLY MORNING CU FIELD AND RECENT SFC INFLOW HAS TIGHTENED THE
BOUNDARY AND CONVERGENCE TO SPARK CONVECTIVE INITIATION.   THE
AMPLE MOISTURE IN THE MID TO UPPER 70S IN NE NC AND THE HEATING
ALONG WITH MODERATE 6C/KM LAPSE RATES HAS SUPPORTED SBCAPES INTO
THE 3000 J/KG RANGE.  GIVEN DEEP MOISTURE AOA 1.75" PER
SOUNDINGS/BLENDED TPW/GPS NETWORK...CELLS WILL HAVE THE CAPABILITY
TO PRODUCE UP TO 2"/HR.

THE 12Z SOUNDING IN MHX DOES SUGGEST SOME MODERATE DRY AIR TO HELP
WITH COLD POOL GENERATION AND WITH INFLOW FROM THE COAST WOULD
NORMALLY SUGGEST EASTWARD PROPAGATION. HOWEVER...WITH THE PASSAGE
OF THE MCV AND UPSTREAM HEIGHT FALLS STILL ROUNDING THE BASE...THE
MID-LEVEL TROF WILL FLATTEN (TIGHTENING THE GRADIENT TO THE WEST)
STRENGTHENING THE UPPER LEVEL JET BUT ALSO RETROGRADING THE
MID-LEVEL FORCING A BIT WESTWARD.  AS SUCH THERE IS FAIRLY TIGHT
HI-RES CAM AND RAPID REFRESH GUIDANCE SUGGESTING FAIRLY STATIC SSW
TO NNE SFC MST CONVERGENCE BAND/UPDRAFT REDEVELOPMENT BAND FROM
JOHNSTON/WAYNE COUNTIES IN NC TOWARD SURRY COUNTY VA.  DEEP MEAN
CELL MOTIONS WILL SUGGEST SOME WESTWARD BACK-SHEARING OF THE
UPDRAFTS BUT OVERALL NORTHWARD MOVEMENT SUPPORTING TRAINING OF THE
MEAN CORES.  SUGGESTING 2-4" TOTALS POTENTIALLY GREATER FURTHER
NORTH INTO SE VA WHERE INFLECTION/CONVERGENCE MIGHT BE STRONGER. 
AS SUCH FLASH FLOODING IS CONSIDERED POSSIBLE THROUGH 00Z.

GALLINA

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

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

LAT...LON   37817684 37597632 37257617 36977599 36647592
            36107646 35577759 35517795 35637826 35937820
            36807765 37497718