AccuWeather’s team of long-range meteorologists is expecting a major outbreak of Arctic air for the western United States next week, but some cold air will also continue to affect the Upper Midwest and northern tier of the Northeast moving forward into late February.
The upcoming colder and wintry pattern will follow a stretch of springlike warmth that may have had some residents across the East suffering from weather whiplash. The colder air is forecast to hold its ground across parts of the central and eastern U.S., potentially leading to some problems in the form of wintry precipitation.
A potent storm is forecast to roll out from the western U.S. during the middle to the latter part of next week and track along the boundary between the cold air across the north and warm air across the South.
While there is still some potential for the storm to track far enough to the south to bring snow or a wintry mix to cities such as Chicago, Detroit, Boston and perhaps New York City, the recent trend in data suggests a more northerly path for the storm, AccuWeather Senior Long-Range Meteorologist Joe Lundberg said.
“The chance of this storm and others to bring snow and/or ice to Washington, D.C., and Philadelphia is quite low through the first part of March,” Lundberg said. “For now, Interstate 80 may be the southernmost cutoff for snow and ice with the storm later next week, but that dividing line may even be too far south.”
The storm can potentially put down a substantial amount of snow and/or ice next week from Minnesota, Wisconsin and northern Michigan to northern New York state and northern New England. Heavy snow may fall north of the mixed precipitation zone in the Northeast and perhaps in some of the bigger cities in Canada.
A key player for the extent of the warmth for next week in the eastern half of the nation will be an area of high pressure that sets up near the Gulf of Mexico.
“High pressure and the associated northward bulge in the jet stream across the Southeastern states will be very strong next week and should work to keep the storm track well to the north,” Lundberg said. “As long as that holds up, it is going to be very hard to get snow to fall in New York City. North of there, the chances are [looking] much better.”
A similar warm setup may prevent snow in Chicago from the storm as well.
Across parts of the southern U.S., temperatures could surge to record-high levels for a time next week.
AccuWeather’s long-range forecasting team closely monitors the polar vortex’s strength year-round.
“The polar vortex is under attack by warm air very high in the atmosphere,” AccuWeather Lead Long-Range Meteorologist Paul Pastelok said.
When the polar vortex weakens, cold air can escape from the massive storm located above the Arctic Circle and reach middle and southern latitudes. However, every southward movement of Arctic air is different, and thus requires close scrutiny from meteorologists to determine where it will head days and weeks in advance. The position of other features often lends a clue.
The position of an atmospheric roadblock associated with an area of high pressure near Greenland-often referred to as the Greenland block by meteorologists-may hold a key for the pattern moving forward during March and April in terms of how much cold air pours into the Northeast, Lundberg said.
“A block that sets up just west of Greenland instead of east of Greenland would be in a much better position to help wedge cold air into the Northeast [to allow] any chance of snow in the I-95 mid-Atlantic,” Lundberg said.
There is some room for colder air to slice across the Midwest and Northeast in late February and early March, and that could allow a storm track to shift slightly farther south.
One potential snowmaker would be an Alberta clipper storm that could drop southeastward sometime from Feb. 27 to March 2. Another could be a more west-to-east traveling storm that would increase the chance for snow in Boston and perhaps New York City, Pastelok and Lundberg concurred.
The majority of abnormally cold air will be into the western third to half of the U.S. from next week to the end of February where daily temperature departures from a historical average of 25, 40 and perhaps even 50 degrees will be possible.
Temperatures have averaged 5-10 degrees Fahrenheit above historical averages since Jan. 1 in much of the Midwest and the Northeast. Departures of this magnitude over a six- to eight-week period are very unusual, forecasters say.
While storms have occasionally been bringing some snow to the Upper Midwest and the northern tier of the Northeast, the snow drought continues farther south.
For example, as of Feb. 17, New York City is 20 inches below its seasonal historic average for snow and has received only 0.4 of an inch. Boston, Philadelphia and Washington, D.C., are all well below their respective historical snowfall averages this winter.
Even in cities farther to the west, such as Pittsburgh, Detroit and Chicago, snowfall has only been 40-60% of the historical average this winter. Snowfall is near or above average only across the northern tier of the Northeast and Midwest.
Produced in association with AccuWeather.
