Then, for Wednesday night there remains some model spread. The
GFS is waffling a bit from run to run with how far north the low
pressure system and subsequent precip shield will get Wednesday
night...the 00z run shifted back south slightly. Meanwhile, the
00z ECMWF and it`s ensemble members actually shifted the low
and axis of heavier QPF/Snow a bit further north and west with
the 00z run. The 00z CMC remains a compromised between the GFS
and ECMWF. All 3 models show a closed 700mb low...but differ on
its track. For this forecast used a blend of WPC/ECMWF and GFS
then made minor edits. This gave QPF amounts of 0.75 to 1.30
inches across the southern tier and all of NE PA.
Still feeling confident that ptype will be exclusively snow for
our entire area, with very cold air in place...in fact as we
wet bulb out and the steady snow begins, it`s likely
temperatures will generally be in the upper 10s to mid-20s
through the event. This should get snow to liquid ratios on the
order of 14-18:1. Again, confidence is increasing that a swath
of heavy snow will impact at least a portion of our forecast
area...but exactly where this sets up remains to be seen. It`s
still too early to pin down any storm total snow amounts from
this potential storm, as it`s about 3.5 days out...but
probabilities for 6"+ are increasing across NE PA and the
Southern Tier/Catskills of CNY. Meanwhile, a tighter gradient is
showing up on the NW edge of the system, with low snow totals
noted by the latest guidance along and north of the NY
Thruway...of course there is still potential for this storm
system to shift further north...or south, which would greatly
impact potential snowfall totals.
https://forecast.weather.gov/product.php?site=BGM&issuedby=BGM&product=AFD&format=CI&version=1&glossary=1&highlight=off