A duo of winter storms are expected in the east this week; the first of two storms is expected to drop snow late Monday into Tuesday/Wednesday, with the second storm expected on Thursday and Friday. While snowflakes could be flying with heavy snow conditions at times, marginal temperatures will lead to only light to moderate snow accumulations from each storm system.
The current weather pattern is not conducive for significant snowstorms in this region this week. A “-AO / -NAO” pattern will be continuing this week and it doesn’t look like AO / NAO will be changing drastically anytime soon. The -AO / -NAO pattern the National Weather Service references deals with the weather pattern over the higher latitudes. The Arctic Oscillation (AO) is a climate index of the state of the atmospheric circulation over the Arctic. It consists of a positive phase (+), featuring below average geopotential heights , which are also referred to as negative geopotential height anomalies , and a negative phase (-) in which the opposite is true. In the negative phase, the polar low pressure system, also known as the polar vortex, over the Arctic is weaker, which results in weaker upper level winds. The result of the weaker westerlies is that cold, Arctic air is able to push farther south into the U.S., while the storm track also remains farther south. The opposite is true when the AO is positive: the polar circulation is stronger which forces cold air and storms to remain farther north. The Arctic Oscillation often shares its phase with the North Atlantic Oscillation (NAO) and its phases directly correlate with the phases of the NAO concerning implications on weather across the U.S.. The NAO consists of two pressure centers in the North Atlantic: one is an area of low pressure typically located near Iceland, and the other an area of high pressure over the Azores. Fluctuations in the strength of these features significantly alters the alignment of the jet stream, especially over the eastern U.S., and ultimately affects temperature and precipitation patterns in this area.
Because of this set-up, the first system moving east into the Northeast will shred apart, not able to intensify in the fast winds. As such, light to moderate snow is possible over the highest elevations of eastern West Virginia, western Virginia, and western Maryland as well as upstate New York, southern Vermont, and western Massachusetts and Connecticut. Because this system is a fast-mover and will be starved for moisture, the heaviest snow totals will be in the 3-4″ range with an isolated 5″ or 6″ amount possible at the highest peaks. Elsewhere, light snow or a mix of light snow and light rain will fall, keeping snow amounts minimal.
Another surface low will develop in the Southeast Tuesday night and then rapidly intensify as it shifts off the southern Mid-Atlantic coast Wednesday night and Thursday. Again, because the weather pattern doesn’t support an intensifying storm off of the Mid Atlantic coast nor is it allowing storms to come up the coast instead of out to sea, this storm too will have little impact. While there could be lingering light snow over central New England, most snow will be from Maryland south into Virginia, where 1-3″ is possible. Some 3-4″ snows are possible over the higher terrain of West Virginia and Virginia as well as the Great Smoky Mountains of North Carolina. 3-4″ is also possible over east central Virginia and southern Maryland where just enough cold air and precipitation could fall from the coastal system before it heads out to sea.
This second system will become intense, but it will slide due east out to sea. If it were to hug the coast, slow down, or move north up into the Northeast, this system could have been a significant snowstorm; perhaps even a blizzard. But because of the current weather pattern, none of these possibilities will happen. Instead, the storm will race out to sea.
For snow lovers, New Jersey and Long Island will be the losers between these two systems. With one sending snow north and the other sending snow south, this area may only see flurries, passing snow showers, or a light rain/snow mix during each storm.