Mesoscale Discussion 2275
NWS Storm Prediction Center Norman OK
1222 PM CST Fri Dec 26 2025

Areas affected…Western New York into northeast Pennsylvania

Concerning…Heavy snow

Valid 261822Z – 262215Z

SUMMARY…A favorable zone for heavy snow banding is becoming
established across parts of western New York into northeast
Pennsylvania. Snowfall rates between 1-2 in/hour will be possible
under any band that develops within this region through late
afternoon.

DISCUSSION…Precipitation banding has begun to emerge across
portions of NY/PA over the past couple of hours amid strengthening
warm air advection between 850-700 mb and increasing, albeit modest,
broad-scale ascent ahead of a low-amplitude upper wave. Dry air in
the lowest few kilometers has limited precipitation amounts at the
surface for most locations thus far; however, automated observations
and web cams between Buffalo and Rochester, NY have begun to report
moderate to heavy snowfall with visibility reductions between 1/2 to
1/4 mile at times under one of the consolidating bands.
Concurrently, NY Mesonet observations are depicting steady surface
moistening with dewpoints climbing by 1-2 F/hour as low-level
profiles saturate under the heavier precipitation bands.

While the heaviest snowfall will likely occur later this evening as
the upper wave moves over the region, these observed trends suggest
that the onset of moderate/heavy snowfall rates is likely beginning.
Areas that can maintain residence time under an established snow
band may observe snowfall rates as high as 1-2 in/hour as soon as
low-level saturation occurs. Favorable overlap of synoptic and
mesoscale ascent will continue to promote snow band development
within the warm advection branch of the disturbance, which will
maintain heavy snowfall potential at least through late afternoon
and possibly into the late evening hours.

..Moore.. 12/26/2025