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One Snowy, Windy Nor’easter Gone; More on the Way?

By: Bob Henson 5:04 PM GMT on February 10, 2017

A fast-moving, hard-hitting snowstorm walloped large swaths of the Northeast U.S. and New England on Thursday, a mere day after record highs above 60°F had enveloped much of the region. Widespread wind gusts of 50 to 70 mph--qualifying the storm as a blizzard for several hours in many areas, including Boston--added to the impact of this classic midwinter event, which dropped widespread snow totals of a foot or more from Long Island, New York, to southwest Maine. Only one fatality had been reported as of Friday morning, a doorman in New York City who slipped and fell through a plate-glass window while shoveling.

The high winds and heavy snow were fueled by a powerful upper-level low sweeping atop the strong low-level temperature contrasts. The result was a very intense surface low that underwent “bombogenesis” near 40°N and 70°W, the benchmark location most closely associated with heavy snow in New York and New England. A bomb-type low requires surface pressure to drop at least 24 mb in 24 hours. Thursday’s storm more than did the trick, with pressures falling from 1002 to 973 mb in 24 hours.

February is the peak month for big snows in the Northeast, and while this storm didn’t smash many records for total accumulation, it was still notably intense, as the fierce winds were accompanied by very heavy snowfall rates. New York’s LaGuardia International Airport received 6” of snow in just two hours, between 8 AM and 10 AM EST Thursday morning, en route to a storm total of 10”.

Figure 1. Pedestrians in western Brooklyn navigate the heavy snow and high winds on Thursday, February 9, 2017. Image credit: Spencer Platt/Getty Images.

The strong temperature and moisture contrasts led to an unusually unstable air mass that generated a truly impressive amount of thunder and lightning for a winter storm (see embedded video at bottom). Matthew Cappucci, an undergraduate at Harvard University, uses data from the National Lightning Detection Network to calculate the number of cloud-to-ground flashes in Northeast winter storms. Cappucci tallied a total of 120 cloud-to-ground lightning strikes with Thursday’s nor’easter. No other winter storm analyzed by Cappucci over the last decade has produced more than 6 strikes, except for the 19 strikes recorded on December 29, 2016. (Thursday was the first time Cappucci himself experienced thundersnow.) A house fire in Providence, RI, on Thursday may have been caused by a lightning strike.

Top snow totals by state, as compiled on Friday morning by the NOAA/NWS Weather Prediction Center, included:

Connecticut: 19” (East Hartford)
Massachusetts: 19” (East Longmeadow)
Maryland: 11.5” (Redhouse)
Maine: 15.4” (near Berwick)
New Hampshire: 17” (Nottingham)
New Jersey: 10” (Vernon)
New York: 16” (Guilderland)
Ohio: 3” (Ravenna)
Pennsylvania: 11.0” (near Champion)
Rhode Island: 14” (Greene)
Virginia: 6” (Hightown)
Vermont: 10” (Woodford)
West Virginia: 8.5” (near Cheat Lake)

See the weather.com roundup for more details on the impact of this storm, dubbed Niko by The Weather Channel.

Figure 2. Larry Habermehl shovels his driveway on King Street in Enfield, Connecticut, on Thursday, Feb. 9, 2017. Habermehl said, "I need the exercise and I don't like plows gouging up my lawn." See this Harvard Health Blog post for tips on how to protect your heart from the risk posed by shoveling snow. Image credit: Brad Horrigan/Hartford Courant via AP.

Figure 3. Seven-day snowfall predicted by the 06Z Friday run of the GFS model for the period from early Friday morning February 10 to February 17, 2017. Longer-range model projections like these can be expected to shift over time in the location and intensity of snowfall. Image credit: tropicaltidbits.com.

More snow likely for parts of the Northeast/New England
After a highly variable but not-too-severe winter thus far, the Northeast and New England are in for a week or more of multiple snowfall threats. This idea is supported by the Madden-Julian Oscillation, which will be very active over the tropical Pacific over the next few days. Large clusters of showers and thunderstorms associated with the MJO can produce upper-level effects that propagate thousands of miles poleward into the midlatitudes. A 2016 paper led by Phil Klotzbach (Colorado State University), showed that when the MJO is active in the tropical regions from the western Pacific toward South America (phases 7 and 8), it tends to boost the amount of snow falling across southeast New England. During Boston’s record-snowy winter of 2014-15, more than 90% of the snow at Logan International Airport fell while the MJO was in phases 7 and 8, according to Klotzbach and colleagues. The MJO is predicted to be quite strong in regions 7 and 8 for the next week-plus (see Figure 4 below).

One potentially major Northeast storm is taking shape for late Sunday into Monday. Like the storm just ended, the Sunday/Monday event will be produced by upper-level energy translating quickly across eastern Canada and the Northeast U.S. rather than digging deeply into the Eastern U.S. This time, the warm sector of the storm should be far enough north to keep precipitation in liquid form along the Washington–New York megalopolis. However, the fast-moving surface low may have just enough time to bomb out east of Boston and help generate heavy snow in the 6” - 12” range (or even more) from upstate New York across northern New England, especially over southern and eastern Maine. Another compact upper-level low will scoot along a similar track later next week. As of Friday, it was unclear whether this impulse will dig enough to produce yet another significant snow for the Northeast and New England.

We’ll be back on Monday with a new post. Enjoy your weekend, everyone!

Bob Henson

Figure 4. Predicted state of the Madden-Julian Oscillation for the period from February 10 to 24, 2017, based on output from the ensemble GFS model. This phase-state map shows MJO energy progressing counterclockwise (eastward) through eight geographic phases, each shown by a map sector defined by dotted lines. The further the MJO is located from the map center, the stronger the activity. The green line indicates the GFS ensemble average, while yellow lines show the individual model runs. Image credit: NOAA/NWS Climate Prediction Center.

Winter Weather Blizzard

The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.