After one of the warmest February’s on record for a large portion of the eastern-third of the nation, a rather un-welcomed change is on the way as we head into March. Temperatures soared past the 60’s all the way up into parts of New England today, but a storm gathering in the center of the country is about to make that a distant memory as just 48 hours from now many of these same areas will be blanketed in inches of snow.
Overnight and into tomorrow morning rain showers will continue to increase across the central and midwestern part of the country, as an area of low pressure begins to deepen just a few hundred miles to the south and east of Chicago. As this storm strengthens, it will pull cold air from the north and begin changing rain over to snow on the extreme northern fringe of the system, stretching from Lake Michigan to Detroit. This will be our first area of accumulating snowfall, with a quick 2-4 inches expected. Some areas closer to Detroit may receive up to half a foot before the snow comes to an end Thursday night.
Meanwhile much of Ohio, western Pennsylvania, and states further to the south will be inundated by heavy rain showers, with temperatures well above freezing and a low pressure right overhead. Thanks to a massive block well to the north, our storm system won’t be able to get very far north, and begin to quickly slow-down. This massive variation in pressure will allow our system to continue developing rapidly, and make for mean “backside” to our storm. Winds will pick up and rain will start mixing with and changing over to snow across Ohio, western Pennsylvania, and western New York overnight on Friday. At the same time, our main low pressure will continue to come to a halt and allow a second area of low pressure to start forming offshore. In meteorology, this is known as a Miller B storm system, where a primary low pressure transfers energy to a secondary low pressure, and allows much colder air to seep in from the north.
Before sunrise on Friday, our team believes that nearly all of this energy will have transferred offshore, and our secondary low pressure will take over entirely just to the south of Long Island. This will mean heavy wet snow and strong gusty winds impacting the region from Buffalo to Albany, and back down into northern and western Pennsylvania. Heavy rain will still be falling across eastern Pennsylvania and the I-95 corridor from Philadelphia to Boston. Flood watches are currently in place for this area as several inches of rain are expected, leading to some localized flooded roadways. That all changes though as we head into Friday afternoon.
Our major blocking high to the north will cause this new secondary low pressure to also slow down significantly, giving it time to manifest over the same location and continuing gaining strength. As it does so, cold air will continue working its way south through the storm, changing rain over to snow down into the Poconos, eastern Pennsylvania, and parts of southern New England. By the mid-morning hours, this cold air moves fast enough that we now expect heavy rain to transition over to heavy snow down into New York City, Connecticut and Massachusetts. Even Philadelphia will see a several hour period of moderate snow on Friday afternoon. As we stated above, the back-end of this storm will be fierce, so along with the quick changeover to heavy wet snow, strong gusty winds will pick up. Even inland areas will be gusting at or above 40 mph, with places along the coast seeing gusts as high as 50 or 60 mph, leading to additional problems. Towards parts of Long Island and the Cape, we can’t rule out a gust or two above 65 mph. Power outages will likely become an issue for many.
During Friday evening and overnight, our storm will be spinning in a relatively similar location, with pressures diving below 980 mb near the center of the storm. For a winter storm system, this is very powerful. Large waves, beach erosion, and coastal flooding could become a major issue, especially for southeastern New England. By sunrise on Saturday, the majority of the storm will be completely offshore, with just some gusty winds and cold air behind.
When all is said and done, we expect a sizable region from Buffalo to nearly Albany to see between 12 and 18 inches of snow, with some higher elevations closing in on 20 or more inches. Central New York and northern Pennsylvania as a whole should see between 6 and 12 inches, with southern New England and parts of eastern Pennsylvania seeing as much as half a foot of snowfall. Even the major I-95 cities could be looking at several inches of heavy wet snow, especially depending on how the back-end of the storm pivots. There may be another shift in our snowfall forecast tomorrow, leaning more on the cold side of things. Stay tuned.