NWS GSP Official Guidance
After record warm temperatures expected Friday, not much in the way of snow in western NC discussed for the weekend:
Key message 3: A complex weekend setup brings more widespread rain
to the area on Saturday, and ushers in much colder air for the
start of the new workweek.
As more pronounced DPVA forcing arrives early Saturday morning and
interacts with the pre-existing
baroclinic zone laid out across
the forecast area, a surface wave will develop within an area of
strong moist upglide, resulting in a resurgence in
rainfall and
thick cloud cover early Saturday morning and persisting for most
of the day.
Ensembles are now in much better agreement on an
early-morning onset, which certainly points to less chance of any
surface-based
instability developing - confidence is increasing
that the setup will be more of a hybrid
CAD-like configuration,
with a
quasi-stationary boundary to our south, and
rainfall
only stabilizing/reinforcing the surface wedge located over us.
Indeed, none of the operational guidance depicts any
sbCAPE over
our southern zones, and the latest long-range
ensembles depict a
<10% chance of significant
instability over even our southernmost
counties.
Surface
cyclogenesis appears
likely somewhere over the eastern
Carolinas as the upper pattern rapidly evolves into a pronounced
longwave
trough spanning the eastern 2/3 of the
CONUS...with
the resultant surface low lifting up the Mid-Atlantic coast and
into New England on Sunday and Sunday night. In response, strong
low-level
CAA will develop across the Carolinas Sunday, ushering
in a much colder, much drier cP
air mass that will linger across
the region for much of next week. Temperatures Sunday, Monday,
and Tuesday nights could fall well into the 20s amid excellent
radiative cooling. Thereafter, the
air mass will steadily modify,
and temperatures will climb to within a couple degrees of
normal
on Wednesday and Thursday.