LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
The pattern change to more wintry conditions will be underway at the
start of the long term portion of the forecast, with temperatures
trending below seasonal levels for Thursday through Saturday.
....
Friday-Saturday, considerable uncertainty regarding the potential
interaction of an upper level impulse tracking from central Canada
into the Plains and Ohio Valley, a strong low/mid level baroclinic
zone persisting from the Gulf Coast to along/off the mid Atlantic
coast, and possible surface low development. The latest 12Z/02 ECMWF
and majority of GEFs members suggest that significant surface low
development remains mainly offshore, although strong forcing from
the main upper level impulse and at least some Atlantic moisture
still may bring some light snow or snow showers sometime late Friday
into Saturday to the region. The 12Z/02 deterministic GFS suggests
stronger surface low development farther west, with perhaps a more
significant snow event impacting the region. At this time, will side
closer to a EC/GEFs idea of at least some snow/snow showers, and
will watch future model/ensemble trends to see if confidence
increases for a more substantial snowfall across at least portions
of the region.
......
http://madriverglenweather.blogspot.com/2017/12/a-few-days-away-big-stretch-of-winter.html
"You just need to go at that shit wide open, hang on, and own it." —Camp