Plenty of uncertainty remains with upcoming winter storm

The weather could turn challenging by the time Monday and Tuesday rolls around for the Finger Lakes. While a ton of uncertainty remains with the track of a system, which will impact the region in some fashion — the likelihood of precipitation (rain or snow) is becoming increasingly likely.

Here’s the latest on the storm setup from FLX Weather Meteorologist Drew Montreuil:

“A complex weather pattern is expected to begin to take place on Sunday over the eastern part of North America which will help spawn a slow moving storm system along the east coast of the United States.

A storm system that is moving into the Pacific Northwest today (Friday) will track east, then south over the Great Plains and into the Deep South this weekend.

On Monday, the system will become better organized over Georgia and will turn northeast towards the Mid-Atlantic and New England states by Tuesday.

Meanwhile, a strong, polar high-pressure system will drop south across eastern Canada and take up residence just north of New England.

This high-pressure system is an extremely important piece of the setup. Not only will it block and slow the progression of the coastal storm, but it will also deliver colder air to the region out ahead of the storm.”

To give some perspective on the types of uncertainties exist with forecasting, Montreuil offered the following explanation:

“An ensemble suite is a set of computer simulations where either the input used to start to the model, or the equations used to run the model, are slightly different for each run. By adjusting the model only slightly each time, a broad look at different possibilities is given.

On Wednesday, I also mentioned the possibility of this event bringing snow to the Finger Lakes. At that time, about 15% of the ensembles were showing significant snow (over 6 inches) in the Finger Lakes. In the latest European ensemble suite, that has jumped to about 25%. Another 40% of the suite members show between 2 and 6 inches. The other 35% show little to no snow.

Overall, the models have been consistent in showing this event. However, as the storm track varies from model to model, so does not only the precipitation type but the amount of precipitation that falls. Looking at precipitation amounts (rain and/or the liquid equivalent of any snow or ice), the ensembles range from less than a quarter of an inch (a very minor event) to nearly an inch and a half (significant event).

The temperatures have trended slightly colder over the last few days, which is shown in the increase in snow on the ensemble suites. However, even the colder solutions are very near to freezing, making this a rather narrow window for wintry precipitation. Any snow that does fall will likely be heavy and wet.”