Valentine's Day Weekend Arctic Outbreak Brings Subzero Cold to Northeast, Midwest

Jon Erdman
Published: February 13,2016



 

The coldest air of the season has plunged into the Northeast this Valentine's Day weekend, after recently impacting parts of the upper Midwest and Great Lakes. This Arctic blast will not only flirt with daily records, but will continue to bring subzero cold to parts of the Northeast and reinforce the cold in the Southeast.
In addition to the bitterly cold temperatures, wind chills are expected to plummet into 30s and 40s below zero over parts of the Northeast. Portions of Upstate New York may see wind chills as low as 50 below zero, while Mount Washington was reporting a wind chill of 80 below zero for a time Saturday night.
This has prompted the National Weather Service to issue wind chill warnings for a large portion of the Northeast, including New England, where "life-threatening" cold conditions are expected.

Wind Chill Alerts

A sharp southward nosedive of the polar jet stream is tapping an air mass originating from the Canadian Arctic, sending it into the eastern half of the country from this weekend through Valentine's Day.
(MORE: What is the Polar Vortex's Role?)
Wind chills plummeted into the 30s below zero Saturday afternoon at Saranac Lake, New York. Subzero cold has also pushed into Buffalo, New York and Boston, Massachusetts for the first time this winter.

Current Temperatures

Let's first break out the timeline of shivering details, then explain why it won't last long.

Daily High/Lowlights

Forecast Highs: Valentine's Cold Outbreak

• Sunday morning: Subzero lows are expected in southern New England and the suburbs of New York City and Philadelphia. Wind chills will be even more brutal dipping into the 30s below zero in portions of Upstate New York and New England. Parts of Upstate New York may see wind chills approach -50 degrees. Farther south, lows in the teens will drive into the Piedmont of the Carolinas. Thirties and 40s will plunge into parts of north and central Florida. The Upper Midwest won't be quite as cold, but should still have some subzero lows, in spots.
• Record Lows Sunday: A few cities that may see records tied or set include Boston (-3 degrees); Worcester (-11 degrees); Providence (-7 degrees); Hartford (-9 degrees); Albany (-10 degrees); New York City (2 degrees) and Philadelphia (2 degrees).

(FORECAST: Buffalo | NYC | Philadelphia | Washington D.C.)

Forecast Lows: Valentine's Cold Outbreak

• Sunday: In the Northeast and Midwest, teens and 20s will be the rule for most on Valentine's Day. The coldest locations of northern New England won't rise out of the single digits. The Carolinas and Tennessee Valley will hold in the 30s and 40s. Some record cold daily high temperatures are possible in the Northeast, including Boston, Providence, Hartford and New York City. 

Several cities in the Northeast could see their coldest temperatures in over a decade this weekend.
Boston's Logan Airport could see their coldest temperature Sunday morning since they dipped to -7 degrees on January 16, 2004. They haven't been colder than -7 degrees since Jan. 15, 1957. In city records dating to 1872, there have been only 27 days during which temperatures have dipped to -8 degrees or colder. All but one of those days were either in the late 19th century or the first half of the 20th century.
Incidentally, subzero cold is quite rare in the city of Boston. They've only had nine subzero lows so far this century, three of which occurred last winter.
New York's Central Park hasn't dipped below zero since Jan. 27, 1994. They'll flirt with that Sunday morning.
A weather balloon launched by the National Weather Service office in Albany, New York Saturday evening measured a record cold temperature of -30.9 degrees Celsius (-23.6 degrees Fahrenheit) at roughly 4,500 feet above the ground. The previous coldest temperature at that level was -30.5 degrees Celsius in January 1981 and again in January 1982.

Why This Won't Last Long

Now for the good news, if you're already starting to get a little winter fatigue. The bitterly cold air will be very short-lived. Temperatures will already begin to warm up a bit starting Monday, and next weekend should be much less cold.

Above: Forecast surface temperature anomalies (above and below average) from the Friday evening mean of the ECMWF ensemble forecast. Note how the coldest anomalies (pink, purple, blue contours) largely disappear by Tuesday.The reason for this is another pattern shift in the new week ahead.

ECMWF ensemble mean forecast made at 7 p.m. ET Friday, of Arctic oscillation (blue), Pacific-North American oscillation (light green) and North Atlantic oscillation (red). Note the AO (blue) and PNA (green) flip sign Feb. 15-16, indicative of the pattern change ahead.
(The Weather Company, Professional Division)

Essentially, the large northward bulge of the jet stream bringing record warmth to the West, including California and the Desert Southwest, will flatten a bit. Weather geeks refer to this as a switch from a positive Pacific-North American oscillation to a negative one.
The corresponding southward plunge of the jet exporting cold air out of Canada into the Midwest and East will then also flatten out next week.
Again, weather geeks would say the Arctic oscillation will switch from negative to positive, meaning the winds around the North Pole will be stronger, keeping the coldest Arctic air bottled up instead of plunging south.
(MAPS: 10-day Forecast Highs/Lows)
So, expect a February thaw after this weekend's shivering in parts of the Midwest and East by the latter half of the week.

However, the warm West-chilly East pattern may reestablish itself by the following week. So, enjoy the thaw while you can.

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