Mesoscale Discussion 1704
NWS Storm Prediction Center Norman OK
0718 AM CST Sun Dec 09 2018
Areas affected...Portions of far western SC...NC...far eastern
TN...southern/central VA...and southern WV
Concerning...Winter mixed precipitation
Valid 091318Z - 091815Z
SUMMARY...Moderate to heavy snow, with rates of 1-2 inches per hour,
will develop northward from western/central NC and southern VA into
portions of central VA through 18Z (1 PM EST). A mix of freezing
rain/sleet ongoing across far western SC into parts of
southern/central NC will shift northeastward this morning before
eventually changing over to rain.
DISCUSSION...A well-defined melting layer aloft was noted on
dual-pol CC data from the KGSP and KRAH radars as of 13Z. A large
area of moderate to heavy snow is ongoing across parts of
western/central NC into southern VA per surface observations and
radar imagery. As a southern-stream shortwave trough continues
northeastward over the Southeast and into the Mid-Atlantic states,
strong low/mid-level frontogenesis will likewise shift northward
into more of central VA through 17-18Z. Heavy snow, with rates of
1-2 inches per hour, will also likely develop into this region as
the low levels saturate and deep lift occurs through the dendritic
growth zone.
Farther south, a narrow zone of freezing rain/sleet is occurring
from far western SC into parts of southern/central NC. Current
expectations are for the low levels to continue to gradually warm,
which will result in a north-northeastward transition of snow to
sleet/freezing rain, to eventually just rain. Before this happens,
several hours of freezing rain, with rates up to 0.10 inch per hour,
may occur. However, temperatures near freezing will probably tend to
limit ice accretion at the surface, except perhaps in higher
terrain.
..Gleason.. 12/09/2018
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...AKQ...MHX...LWX...RAH...RNK...RLX...CAE...GSP...
MRX...
LAT...LON 35288307 35808303 37008259 37498195 37828133 38078043
38267957 38257865 38007776 37687716 37267682 36917675
36347703 35847757 35247905 34968019 34698193 34798275
35288307