Winter Storm Watch for Potentially Heavy and Wet Snow Friday

JAMESTOWN – The National Weather Service in Buffalo has issued a Winter Storm Watch, which will go into effect Thursday night, lasting through Friday night, for all of Western New York. 
We’ve been going over every piece of data we can get our hands on, trying to get a better handle on this winter storm, which we first talked about back on Tuesday.
There are still uncertainties with the exact amount of snowfall we could see out of this. Many of the questions from yesterday still remain, which is making this event very tricky to forecast.
Here are our current thoughts based on the newest data:
A widespread rain will cover Western New York throughout the day on Thursday. The actual center of the storm, or the Low pressure area, will track east and south of our region throughout the nighttime hours.
The storm will pull down cold air from Canada, setting up a changeover from rain, to all snow, as we work throughout the wee morning hours of Friday. Here’s where the weeping and gnashing of teeth begins.
What is still unclear is, when does the transition period begin, how long will the transition last before it’s complete, and could Lake Ontario get involved in the action as well?
Our exclusive VIPIRCast computer model that we run right here in-house, points to a transition starting just after midnight, and lasting through the wee morning hours, as the colder air will be gradually worked in, with the changeover to all snow complete by 5 or 6 AM.
If that would be the case, that slow of a transition time would allow for a bigger window of rain or sleet to fall during the changeover period, likely keeping overall snow totals down.
While some of the global computer models have the same idea as VIPIR, some of them are the complete opposite; a rapid changeover occurring within just a couple of hours, as the cold air is quickly worked through the area.
If that idea comes to light, the amount of snowfall we could see would likely be significantly more.
It’s also on the table that areas south of Rochester, into the Bristol Hills, could add some lake enhancement into the mix, as northwest to northeast winds driven off Lake Ontario may trigger a response from the lake, adding to the snow totals.
In terms of the snow totals, we still cannot give exact numbers for exact locations, but given the data we have, several inches of a general snowfall is a good estimation, but with significantly higher amounts likely along higher terrain, especially out towards Rochester and points south, IF lake enhancement comes into play.