I really like CTP’s current discussion regarding Monday night/Tuesday.
The main system of consequence will affect our region Monday
night and Tuesday, in the form of a storm system tracking from
the southern Plains northeastward through the Great Lakes
region. A storm track of this nature well west of the
Commonwealth should ultimately bring in enough warm air aloft
for a transition from snow to a wintry mix. However, with a
stubborn cold surface high sitting up across eastern Ontario and
Quebec, surface-based cold air will be tough to dislodge over
much of central PA east of the higher ridges. The strength of
the northerly ageostrophic flow late Monday night into Tuesday,
along with model sounding profiles, indicate that a prolonged
period of sleet is possible, with some freezing rain as well.
At this point, a general 1-4" of snow seems quite plausible
Monday evening, followed by a coating of ice via sleet and
freezing rain later Monday night and Tuesday. Certainly, a messy
morning commute Tuesday seems likely, so stay tuned for more
specific details as this event nears.
It`s questionable how much of the region is able to rise above
freezing Tuesday afternoon, with some of our far western and
southern areas the most likely candidates to see a period of
rain, before drier air aloft comes in.