NEAR TERM /THROUGH FRIDAY/...
As of 100 pm:
Water vapor imagery shows upper low centered over
northern Miss. Associated
cirrus shield will continue spilling over
the
downstream ridge into the forecast area throughout the
afternoon, although there are enough areas of breaks and thinning
such that most areas will see periods of at least filtered sunshine
through the afternoon. This should allow for enough
insolation to
support maxes in the 45-50 range east of the
mtns, and 40-45 in the
mtn valleys.
Model consensus carries the surface low south of the I-20 corridor
late today through Friday morning, with the core of the upper
low moving near the southern border of TN and
NC during this
time frame. This will place most of the
CWA just on the cool side
of the warm
front. Most of the area will start off well above
freezing in the early evening;
moisture will quickly deepen as
the
sfc/upper low encroach on the area before midnight, bringing in
precip chances from the SW. The strongest dynamic forcing will
precede the upper low into the area, peaking in the predawn hours
Friday, with the better
moisture lagging the forcing somewhat. The
best frontogenetic forcing will occur nearer the warm
front. Precip
is still tricky, mainly east of the
mtns, and perhaps across the
mountain valleys of southwest
NC. There will be a lot of midlevel
dry air to overcome early in the event, and the
WAA gives us a weak
warm nose as well (though not as strong as we often see with these
sorts of systems). The higher mountains
likely will see snow through
most of the event, but lower elevations and areas further south will
see some period of sleet, or perhaps even freezing rain where the
warm nose (along with evaporative cooling diminishing it at least
locally) is present. Confidence is sufficient such that all zones
in the
Watch were converted to a
Warning earlier this morning with
the exception of Catawba, Iredell, and Davie Counties in
NC. This
area will take longer to see accumulation reach any criteria, but
this area (plus Rowan County) is receiving strong consideration for
upgrade to
Warning over the next 1-2 hours. Areas closer to the I-85
corridor are being considered for a potential Winter
Wx Advisory.
With the upper low crossing the area during the day Friday, even as
winds turn more downslope and
moisture becomes more shallow, there
will remain support for significant precip as the deformation zone
scrapes the
NC Piedmont. Temperatures will be held nearly steady in
the 30s where the precip is ongoing, and many areas will continue to
see snow during the day, possibly mixing with rain. Strong lapse
rates under the low may allow enhanced precip rates and snow will be
more
likely during those periods. The event will transition to
northwest
flow late Friday across the
NC/TN border area as
PoPs
continue to drop off east of there.