If you liked last winter in Central Maryland — pretty cold, but with below-average snow — you may get a chance to live it over again this winter.
Forecasters at AccuWeather.com say the country is in for a second La Nina winter in a row, with brutal cold and snow across the northern tier of states.
For Central Maryland, the annual pre-season forecast calls for no worse than near- to "slightly below-average" snowfall, but with some risk of a few "significant" snow or ice events.
"If we're going to get a disruptive storm, it's going to be in December or January," said AccuWeather.com senior forecaster Jack Boston. "I don't think much of the chances in February.
"For temperatures, I think they're going to be below normal December and January," he said, "and when the flip happens in February, it goes back above normal."
That's not far from what the region endured last winter. It was colder than average in December and January, warming up a bit by February.
The snow stopped at 14.4 inches — almost a half-foot below Baltimore's 30-year average of 20.2 inches. But the area did have several disruptive storms, including the nightmarish one on Jan. 26 that snarled the morning commute, only to snare drivers again with snow-slicked roads on their way home.
Dozens of trucks jackknifed, helping to jam the highways and trap thousands in their cars for hours.
The National Weather Service, meanwhile, is predicting much the same winter weather pattern, with colder-than-average temperatures across the northern states as far as the Great Lakes, generally dry and mild readings across the South, and no strong departures from the averages for the Mid-Atlantic states and New England.
The key to all the forecasters' predictions for this winter is La Nina, the cold phase of the El Nino/La Nina cycle of surfaceocean temperatures in the eastern equatorialPacific Ocean.
Last winter's La Nina waned to "neutral" in the late spring and summer. But instead of shifting into the warm "El Nino" phase, the Pacific's surface waters cooled again, leading into a second La Nina in a row. It's happened several times in the past decade, most recently in the winter of 2007-2008, and again the following winter, Boston said.
La Nina winters can offer a break for the Mid-Atlantic. The last El Nino winter was in 2009-2010, which became the snowiest winter on record for Baltimore, with 77 inches of snow.
In a La Nina winter, Boston said, the winter storm track comes out of central Canada, across the Great Lakes and into the Mid-Atlantic as "Alberta Clippers," arriving with frigid air masses in December and January. "We can see that pattern starting to re-arrange itself, so that can happen as soon as two or two and a half weeks from now," he said.
Unlike storms that come across the Gulf states and up the Atlantic coast — common during an El Nino winter — "this kind of [clipper] storm is not going to give you 30 inches of snow at one time. It brings three or four… maybe eight inches if it all worked out," Boston said.
Only if such a storm reformed along the South Carolina coast could its fortunes turn. "Then look out Baltimore and Washington!" he said.
But the La Nina pattern will be a much bigger threat this winter from the Central Plains as far east as the Ohio Valley, where Boston predicted "very cold, if not record cold arctic outbreaks."
"Minneapolis is in for a very cold, snowy winter, as are Chicago, Milwaukee, Indianapolis, Detroit, Buffalo," he said. "It looks like a real good year for lake-effect [snow]."
Across the Southwest and West Texas, AccuWeather.com calls for "mild and dry" weather, while eastern and northern Texas could do better as cold fronts drop down from Canada with higher chances for some rain.
"The other thing we're going to hear about is the Tennessee Valley," Boston said. "With cold air masses getting so far south … those areas end up with above-normal snowfall." Snow, sleet and freezing rain are also in the cards from Oklahoma to Kentucky.
Late in the winter, as cold air hangs on to the north and warm air begins to push in from the South, the central U.S. will also likely see some violent weather. As in 2011, he said, "we're looking at tornadoes in February in the Lower Mississippi Valley."
In another potential repeat, he added, "There's also a potential for flooding, I think around the same time as the warm air tries to return north."
http://twitter.com/froylanceCopyright © 2015, The Baltimore Sun