BETHLEHEM, Pa. — Is winter over?
There have been more than a few headlines in recent days declaring an end to the season, but no meteorologist in his or her right mind would say as much at this point in February — especially in the Mid-Atlantic and Northeast.
Especially in a year where the Lehigh Valley has recorded more snow than Boston (25.2 inches vs. 9.7 inches, for those keeping score at home).
Even in a pattern change that shows temperatures set to surge into the 60s next week in some areas.
Why?
There’s a growing chance that Old Man Winter will deal us a bitter blow before the season's end, experts say.
Let’s break it down.
Polar vortex to unleash cold, stormy conditions?
On March 10, less than three weeks from now, we will enter daylight saving time and our sunset will be at 7:03 p.m.
Nine days later, the vernal equinox will officially mark the beginning of spring in the Northern Hemisphere.
But meteorologists say there are a number of variables complicating the long-term forecast, and one of them could be a Sudden Stratospheric Warming event, or SSW — a breakdown of the polar vortex.
Such an event would send a pool of cold air spilling into the Lower 48, and experts say models are indicating this possibility around mid-March.
In fact, long-range forecaster Judah Cohen told the Washington Post the vortex disruption could be “fairly large.”
He’s not the only one sounding the alarm.
This potential major SSW also is a sign of caution about posts proclaiming winter (or at least below normal temps) is “over”.
— Tomer Burg (@burgwx) February 21, 2024
Early March looks mild across the eastern half of the U.S… but with growing signals for *potential* high latitude blocking mid-March onward. https://t.co/sxRpUP2eVl
“This potential major SSW also is a sign of caution about posts proclaiming winter (or at least below normal temps) is 'over,'” Tomer Burg, an atmospheric scientist who recently joined the team at the NWS Weather Prediction Center, said on X.
“Early March looks mild across the eastern half of the U.S… but with growing signals for *potential* high latitude blocking mid-March onward."
Storms could thread the needle
EPAWA meteorologist Bobby Martrich has cautioned his audience in recent days that storms in March and early April always have a chance to “thread the needle,” meeting up with cold air at just the right time.
If the polar vortex collapses and displaces frigid air, it could set the stage for a period where wintry weather will be very possible for the Lehigh Valley and the rest of the region.
The caveat, of course, is where the lobes of cold air will end up. But experts say if the cold intrudes in our area, it could establish storm tracks that could favor more active weather.
It would also be our second sudden stratospheric warming event of the season, following a disruption in January.
But…
As Burg pointed out on X, mid-March onward is a period where it’s “increasingly tough to get snowstorms unless there’s an exceptionally favorable synoptic setup with ample cold air aloft."
“As for the interior Northeast, however, major snowstorms are still climatologically possible even into April,” he said.
Meteorologist John Homenuk also posted about “nearly unanimous agreement” on models for high-latitude blocking and cold air to return.
But on his blog, Cohen tempered expectations ever so slightly.
“Winter is running out of runway,” he wrote. “So even though all the models are predicting an ongoing large polar vortex (PV) disruption, the impacts to our weather are questionable.
“Given the strengthening sun will it result in cold and white or just cool and wet?”
Time will tell. Until then, enjoy our preview of spring next week.
