High pressure will build across the region through tonight giving many folks a welcome break from the recent winter weather. Some areas will even see some sunshine this afternoon.
A low pressure system over the northern Rocky Mountains will move east-southeastward into the Great Lakes on Thursday then into the eastern lakes Thursday night. Meanwhile, another low pressure system over the southern Plains will move through the southeastern United States to the Mid Atlantic coast by Friday morning.
Light rain or snow showers will be possible across much of the region on Thursday. The best chance of accumulating snow on Thursday will be from central Lower Michigan, northward. Precipitation amounts across the eastern lakes should be light.
By Thursday night these two low pressure systems will begin to interact. Precipitation will spread eastward across the region Thursday evening into Thursday night. The precipitation will likely fall as snow from Lower Michigan, eastward across Ontario and into western New York State. South of this area, across northern Ohio and northwestern Pennsylvania, a mix of snow, sleet, freezing rain, and rain can be expected with all rain further south.
Late Thursday night or Friday morning the two storms will phase into a single powerhouse storm along the northern Mid Atlantic coast, with a trough of low pressure extending northwestward across the eastern Great Lakes. Colder air will be drawn southward on the back side of the deepening coastal storm. This will change any rain or mixed precipitation over to snow across Ohio and Pennsylvania with snow continuing across western New York.
During the day Friday, the coastal storm will bomb out while moving northeastward to the New England coast. The trough of low pressure over the eastern lakes will remain in pace with snow continuing for the eastern half of the region. Snowfall amounts across western New York and western Pennsylvania could be significant, depending on the track of the coastal low.
There are many uncertainties regarding the evolution of this complex system that make forecasting the location and amount of snowfall very difficult. At this time, the best chance of seeing significant snow (greater than 6 inches) will be east of a line from Rochester, New York to State College, Pennsylvania with lighter amounts further west. Of course, this is subject to change. If the systems phase sooner, the heavier snow could be further west. If they phase later or are weaker, then the heavy snow will be further east and more of the region will see a mix of precipitation.
Stay tuned for updates as the system approaches and forecast becomes more clear.