From NWS in Raleigh's AFD
Developing low level onshore flow on the SE side of the exiting
ridge, along with increasing 850 mb flow from the SSW between the
approaching trough and the strengthening anticyclone off the
Southeast coast, will lead to a quick increase in clouds spreading
in from the S and W. The initially shallow moist upglide around 280K
will strengthen and deepen up through 300K, particularly over the
far W CWA, through the night. While the low level jetting will be
pronounced and quite warm, lingering cold dry surface air locked in
over the W Piedmont will initially hold surface wet bulb temps below
freezing and result in a threat of patchy light freezing rain or
freezing drizzle mainly after midnight. Given the fairly shallow
moisture depth and limited areal extent of the moist upglide, any
icing should be very light. But any icing would be worthy of an
advisory, and this potential will be watched closely. Temps are
expected to bottom out in the upper 20s to lower 30s Tue night.
Increasing and deepening warm air advection should eventually help
dislodge the vulnerable cool stable air, although this process
should be delayed over much of the Piedmont. Expect highs from
around 50 NW to around 60 in the Triangle area and the low-mid 60s
across the Southeast CWA, under mostly cloudy skies. Will retain a
small chance for light rain and showers, mainly over the W half, as
the moist upglide diminishes. Amounts will be light. -GIH
