Thursday-Friday storm: it's complicated

Update #527a

It’s complicated, but I’m here to help ☺️

Mother Nature is all gas, no brakes this week! 💨 It’s pedal to the metal toward the next storm, which will accelerate into the region late Thursday afternoon.

It’s the type of storm during which there will be entirely different weather on one side of the valley compared to the other. It’s the type of storm that makes a meteorologist yearn for simpler times when the whole region experiences similar conditions.

🤷‍♂️ Alas, it wasn’t meant to be. Maybe next time!

The complexity has to do with a battle between a retreating cold air mass and an incoming milder one. While a coastal low pressure system will form, it will be far from the quintessential nor’easter which maintains a steady flow of cold air into the region.

Getting to it, here’s what we’re working with:

What? Wet snow, some heavy, particularly across Orange (especially west), Ulster, and Sullivan County. The higher your elevation, the higher your chances for heavy snow. The snow will probably change to rain across Dutchess, Putnam, Rockland, and Westchester County and mix with rain in Orange and Ulster County.

When? Starting between 3:00 - 7:00 pm Thursday from southwest to northeast — this means that it will start first in southwestern Orange County and last in northeastern Dutchess County. The start time will be refined over the next day. It will have a bearing on whether or not schools will need to consider dismissing an hour or two early and/or cancel after school activities.

How much? Given the complexity of the storm, this is subject to change! Potential for more than 6 inches in Sullivan and western Ulster County. 3-6 inches for Orange and eastern Ulster County. 1-3 inches for Dutchess and Putnam County. Up to an inch for Rockland and Westchester County. A “boom scenario” (less likely) would involve more than 6 inches across much of the region.

The map below offers a look at the possible distribution of snowfall across the Hudson Valley and Catskills. It will change, but it provides the general idea of there being more snow in the west and across the higher elevations (green colors).

Indicative forecast snowfall through Friday; the legend on right shows what each color means

Impact? Potential for snow-covered or slushy roads from Thursday evening into Friday morning in Orange (especially west), Ulster, and Sullivan County. Some chance for similar conditions in Dutchess and Putnam County and a lower chance in Rockland and Westchester. Improving conditions are favored on Friday, except in the Catskills where wintry impacts will likely linger on — I have a concern for the possibility of downed trees and power lines there.

As it pertains to school:

• Thursday: dismissing an hour or two early may need to be considered, depending on the start time — especially in Orange and Sullivan County where snow will start first. After school activities may need to be cancelled regionwide.

• Friday: the potential for a snow day is highest across western Ulster and Sullivan County. A snow day or delay is possible for Orange and eastern Ulster County, with the chances not as high for the remainder of the region.

I will hold off on issuing school percentages until tomorrow when the forecast will offer more confidence.

Until then, hopefully this gives you some useful information to work with! I’ll be in touch again tomorrow morning. Have a great day!