MESOSCALE DISCUSSION 0140
NWS STORM PREDICTION CENTER NORMAN OK
0757 AM CST FRI FEB 21 2014

AREAS AFFECTED…CNTRL VA THROUGH CNTRL AND SERN NC AND NERN SC

CONCERNING…SEVERE POTENTIAL…WATCH LIKELY

VALID 211357Z – 211500Z

PROBABILITY OF WATCH ISSUANCE…80 PERCENT

SUMMARY…STORMS ARE EXPECTED TO INCREASE THROUGH NERN SC…CNTRL NC
AND CNTRL VA THROUGH THE MORNING. DAMAGING WIND AND A FEW TORNADOES
WILL BE THE MAIN THREATS. WW WILL LIKELY BE NEEDED BY 15Z.

DISCUSSION…BROKEN LINE OF LOWER TOPPED CONVECTION EXTENDS FROM
SWRN VA THROUGH WCNTRL NC MOVING EAST AT AROUND 35 KT. DOWNSTREAM
FROM THE LINE A WARM FRONT HAS BEEN ADVANCING NWD THROUGH VA WITH
DEWPOINTS GENERALLY IN THE LOW 60S IN THE WARM SECTOR. THE 12Z RAOBS
FROM GREENSBORO NC AND CHARLESTON SC SHOW ONLY A VERY SHALLOW
NEAR-SURFACE STABLE LAYER AS WELL AS A WEAK MID-LEVEL INVERSION
CENTERED AROUND 600 MB. THOUGH DIABATIC WARMING WILL BE TEMPERED BY
WIDESPREAD CONVECTIVE DEBRIS…TEMPERATURES ONLY IN THE LOW 70S WILL
BE NEEDED TO SUPPORT SURFACE BASED PARCELS. WITH TIME THE MID-LEVEL
INVERSION WILL ALSO LIKELY BE ELIMINATED AS ZONE OF DEEP ASCENT
ALONG THE CONVEYOR BELT SHIFTS EWD. STORMS ARE EXPECTED TO INTENSIFY
AS THEY ENCOUNTER GREATER INSTABILITY /UP TO 1000 J/KG MUCAPE/.
STRONG 0-1 KM SHEAR ASSOCIATED WITH THE MIGRATORY 60 KT SLY LLJ AND
STRONG EFFECTIVE BULK SHEAR WILL SUPPORT ORGANIZED STRUCTURES WITHIN
THE LINE…INCLUDING EMBEDDED MESOCYCLONES AND BOWING SEGMENTS.
ALSO…STORMS MAY DEEPEN FARTHER EAST ALONG PRE-FRONTAL CONVERGENCE
BANDS EMANATING FROM THE GULF.