The CO one will be the first
feature of interest as it moves a little more quickly to the east by
hitching a ride on the tail of a pseudo-zonal subtropical jet over
the SE US, while the ND system will move eastward at a slower pace.
A weak surface and elongated trough will develop ahead of these
features with some precipitation development along the trough axis
by Sunday evening. For snow lovers, this is not an awe-inspiring
setup as it is lacking in synoptic lift and mesoscale help from
nearby lake influences. The result may be some light snow to our
south and possibly over the Southern Tier, with a lower chance for
much of Western and Central NY as the weak surface trough stretches
out over the region. Even if snow does fall, accumulations look
rather sparse with best chance scenarios of around and inch or two.
On Monday, the ND shortwave will be over the Northern Great Lakes
and approaching the region. This will provide another opportunity
for some snow, with a little more help from the lakes on a WNW flow,
meaning to some extent the Chautauqua Ridge and (better) areas SE of
Lake Ontario will have another chance to see some snow showers
before and on Christmas Eve. Upper level support is there with the
shortwave, along with the airmass aloft just cold enough to for
lapse rates supporting snow together with a cap around 10000`.
Moisture is there too, at least through the dendritic growth region,
although synoptic moisture isn`t impressive beyond the cap. With
the above in mind, multibanded snow showers are a possibility with
the usual relatively low confidence ~2 days for WNW flow. But at
least there`s something to latch onto however. As usual, with this
flow, the hardest area to forecast for will be the Niagara Frontier
with the low possibility of a weak `gotcha` band originating off
Lake Huron.