SPC MESOSCALE DISCUSSION 0006 FOR CENTRAL NC...NERN NC...AND
EXTREME SERN VA
CONCERNING...HEAVY SNOW...

VALID 030050Z - 030700Z

SNOW WILL MOVE INTO CENTRAL NC LATE THIS EVENING AND INTO SERN VA
DURING THE EARLY MORNING HOURS WITH MAX SNOW RATES BETWEEN 1-1.5
IN/HR OVERNIGHT. 

STATIONARY FRONT EXTENDS NEWD FROM 1010MB LOW NEAR MLB TO 100E
HAT...WITH FRONTAL ZONE SLOPING VERY SHARPLY NWWD WITH HEIGHT INTO
CENTRAL NC AROUND 1-1.5 KM AGL BASED ON CAE AND RDU VAD WIND
PROFILES AND ETA CROSS SECTIONS. STRONG ISENTROPIC UPGLIDE WILL
TRANSLATE NEWD OVERNIGHT AND COMBINED WITH A DEVELOPING DEFORMATION
ZONE ACROSS CENTRAL NC...INDUCE VERY STRONG FRONTOGENESIS FORCING
IN THE 800-700MB LAYER FROM RDU NEWD TO THE NERN NC/SERN VA BORDER
WITH TIME. THIS WILL BE THE FOCUS FOR HEAVIEST SNOWFALL RATES
OVERNIGHT. WHILE MODEST LAPSE RATES WILL KEEP SYMMETRIC STABILITY
HIGH AND PRECLUDE SMALL-SCALE BANDED PRECIPITATION STRUCTURES...
AMPLE MOISTURE AND LARGER-SCALE WARM ADVECTION SUGGESTS ENVIRONMENT
WILL BE CONDUCIVE FOR 1-1.5 IN/HR SNOW RATES IN A 50-70NM WIDE
CORRIDOR FROM RDU BY 04Z...TO 45N RWI AND ENEWD TO 20S ORF VERY
LATE TONIGHT. DRIER BOUNDARY LAYER AIR WEST AND WEAKER FORCING FOR
ASCENT WILL TAPER SNOW RATES OFF TOWARD THE NORTH AND WEST OF THIS
AXIS.   

IN TERMS OF PRECIPITATION TYPE...LOW-LEVEL NELY FLOW WILL GRADUALLY
BACK TO NLY AS SURFACE CYCLONE MOVES SOUTH AND EAST OF THE REGION
ALONG SURFACE FRONTAL BOUNDARY...MAINTAINING A THERMAL
STRATIFICATION CONDUCIVE FOR SNOW WITH THE EXCEPTION OF THE
IMMEDIATE COAST OF NERN NC/SERN VA WHERE A RAIN/SNOW/SLEET MIX IS
LIKELY. THIS IS CONSISTENT WITH EXPERIMENTAL NCEP PRECIPITATION
TYPE GUIDANCE BASED ON THE 12 AND 18Z ETA.  

..BANACOS.. 01/03/02