Is Winter Over? With Springlike Temperatures Ahead, You'd Think So
At a Glance
Generally warmer-than-average temperatures are expected in much of the nation through mid-March.
Some locations will enjoy their first 60s or 70s of the season early this week.
Early March snow cover is the lowest in the U.S. in at least 16 years.
However, snow in March, April, even May is typical in some parts of the country.
The first day of astronomical spring is still over a week away, but you wouldn't know it by the recent weather.
In the Northeast, despite a powerful lake-effect snowstorm at the end of the month, February was among the least snowy on record along the Interstate 95 urban corridor. Boston was the only major city in that corridor to receive any measurable snow.
Recent warmth eroded snowpack over the Lower 48 states to its lowest aerial coverage for March 6 in at least 16 years, according to NOAA's National Operational Hydrologic Remote Sensing Center – a stark contrast to the record-smashing cold and widespread snow cover in place one year ago.
And, according to the National Phenology Network, the spring leaf-out is occurring as far north as parts of the mid-Atlantic, up to three weeks earlier than average.
One reason for this benign winter was the tendency for the jet stream to steer cold, Canadian air eastward across North America, rather than plunging it deep into the U.S. and locking it in place, what meteorologists refer to as the positive phase of the Arctic Oscillation. A persistently strong polar vortex high above the Earth in the stratosphere likely was a factor in this pattern.
Also lingering into mid-March: the jet stream's southward dip in the West.
When that happens, the jet stream tends to buckle northward in the central and eastern U.S., allowing relatively warm air to push northward into the Plains, Midwest and East.
That doesn't mean cold fronts won't sweep through the country and knock temperatures down from time to time; That's just part of March's often frustrating weather.
But it does mean that warmer weather will dominate in much of the eastern half of the country over the next week or two. The colder air behind each front won't be all that cold, and it won't last long
before a warmup ensues.
More Warm Weather Incoming
The next warm surge will spread from the Plains and Midwest into the Northeast early this week.
On Sunday, Minneapolis had its first 60s – and Omaha, Nebraska, its first 70s – since last October.
Philadelphia might record its first 70-degree day since last October on Monday.
NOAA's latest 6- to 10-day outlook indicates that most of the central and eastern United States is expected to be warmer than average through the week of St. Patrick's Day, particularly in the South and East.
Spring Snow Still Possible?
This doesn't mean it's time to put the snow thrower away for the season.
From the interior Northeast across the Great Lakes into the Northern Plains, the season's final snow typically falls in April. In the Mountain West, that could occur in May or later.
Last spring, Chicago had its snowiest April since 1982, with separate snow events on April 14, Palm Sunday, then again on April 27.
So we can't rule out one or more potent spring snowstorms that may have just enough cold air to blanket the ground with heavy, wet snow.
But for at least the next couple of weeks, that chance seems small east of the Rockies.
And this stubborn jet stream pattern would have to change appreciably to allow winter weather to make a comeback in April.