By Ellen Wulfhorst
NEW YORK, Feb 26 (Reuters) - A recent stint of warm days and sunshine in the U.S. Midwest and Northeast was just a tease, as forecasters on Wednesday predicted an extended stretch of bitter cold and snow reaching well into March.
The wintry conditions were likely to take a firm hold on Thursday in the Midwest and move eastward over the weekend, meteorologists said.
"Once again the polar jet stream has plunged southward, tapping bitter cold air directly from the Arctic Ocean. This latest frigid plunge will engulf the nation's northern tier through the weekend," wrote The Weather Channel meteorologist Chris Dolce on its website.
The arctic air mass was affecting the eastern two-thirds of the nation on Wednesday, with high temperatures some 15 to 30 degrees Fahrenheit below normal in many places, the National Weather Service said.
On Friday and Saturday a "long-duration snow event" will develop in the central United States and slowly move east, said Alex Sosnowski, senior meteorologist at Accuweather.com.
West to east, snow may fall over a distance of 1,500 miles, affecting Chicago, St. Louis, Detroit, Cincinnati, Pittsburgh, Washington D.C., Philadelphia, New York City and Boston, he said.
"At this early stage, the storm has the potential to bring half of a foot to a foot (15 to 30 cm) of heavy wet snow to some locations in the Midwest and East, with locally higher amounts," he wrote.
Accuweather predicted wintry conditions to keep a grip east of the Rocky Mountains until the third week in March, when the nation will then see "a chilly spring weather pattern."
A recent break in the weather brought a high of 64 degrees F (18 C) in St. Louis on Saturday and highs on Friday of 56 F (13 C) in Cleveland and Pittsburgh.
The Midwest and Northeast have seen a string of powerful storms this winter that have stretched salt supplies and clean-up budgets to the limit.
Spring officially begins on March 20.
(Reporting by Ellen Wulfhorst; editing by Gunna Dickson)