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Big Cities Largely Spared by Northeast Storm; Huge Totals Piling Up Inland

By: Bob Henson and Jeff Masters 5:30 PM GMT on March 14, 2017

Even though Tuesday’s much-anticipated storm (dubbed Stella by The Weather Channel) was producing more of an icy mess than a winter wonderland along the corridor from Washington, D.C., to New York, it wouldn’t be entirely fair to call it a bust. Power outages were piling up quickly at midday Tuesday throughout the region as fierce winds battered the area, gusting well above 40 mph along the coast from New Jersey to Massachusetts. Precipitation has been very intense, just as expected, and you don’t have to go far inland from the Interstate 95 corridor to encounter extreme snowfall.

Mount Pocono, PA, had received 23.0” of snow as of 11 am EDT Tuesday, and Endwell, NY, just west of Binghamton, had racked up 18.3” as of 10 am. Highland Lakes, NJ—only about 30 miles northwest of Manhattan—reported 14.5” as of 10:25 am, with an astounding 4.5” of snow reportedly falling in just one hour.

Figure 1. The Weather Channel's Jen Carfagno reports on Winter Storm Stella from the Tidal Basin in Washington, D.C. on Tuesday, March 14, 2017. (Kevin Wolf/AP Images for The Weather Channel)

Conditions were already improving in the Washington area at noon Tuesday, according to Capital Weather Gang. Snow totals in the District have been fairly underwhelming, around 2” - 3”, although the White House CoCoRaHS station reported a healthy 2.34” of liquid equivalent.

Near I-95 in Pennsylvania, the snow turned to freezing rain and sleet early Tuesday morning. The National Weather Service office in Philadelphia relayed several reports of 1/4” ice accumulations (“…what could have been snow,” the office pointed out). Snowfall in the Philadelphia metro area was generally in the 3” - 4” range as of late Tuesday AM.

While more than a foot had fallen by midday across New York City’s northern suburbs, Central Park had received only 4” as of 8:00 am EDT, with lighter snowfall reported after that point. Further upstate, far eastern New York and western New England were on track to get very heavy snow toward Tuesday afternoon and evening. As of 10:40 am EDT, the most likely totals predicted by the NWS/Albany office include 18” - 24” in the Albany area and 24” - 30” in far southern Vermont.

Figure 2 People struggle to walk in heavy windblown snow on Tuesday, March 14, 2017, in Boston. Image credit: AP Photo/Michael Dwyer.

After a quick burst of snow Tuesday morning, southeast New England will be experiencing mostly rain as a wedge of warmer air surges into the region. Boston will be on the knife edge of the snow/rain transition zone, which makes the ultimate snow totals there very hard to call. “Snow accumulations are quite difficult [to predict] across eastern New England because of the extreme snowfall rates likely at the time of the changeover,” explained the Boston-area NWS office. “Being off by an hour or two on the changeover will have huge implications.”

Most of Maine should stay on the snowy side of the developing coastal front, although a changeover could occur along the mid-Maine coast as the intense surface low moves nearby. Portland, ME, may end up in the running with Albany, NY, for the heaviest accumulations in a sizable Northeastern city, with as much as 18” possible.

Figure 3. Observed water levels above MLLW (mean low low water) at Atlantic City, New Jersey, on March 13-14, 2017. The MLLW level (red trace) peaked at 7.8 feet above MLLW at 9:18 am EDT Tuesday morning, March 14. This corresponded to a peak storm tide (the height of water above the high-tide mark, or the difference between the red and blue traces) of 3.40 feet. Image credit: NOAA TIdes and Currents.

A modest coastal flooding threat by nor’easter standards
The exceptionally strong winds of Stella drove a storm surge of 1 - 3.5 feet on Tuesday morning along the coasts of Virginia, Maryland, Delaware, New Jersey, and New York. The most notable storm surge occurred at Atlantic City, New Jersey, where the storm tide (the height of the water above the high tide mark) reached 3.40 feet—placing it #9 in the top ten list of highest water levels on record for the city. (The previous tenth-highest water level in Atlantic City's recorded history was 3.24’, set during last year’s nor’easter on January 23, 2016; the highest was 4.38’ during the December 11, 1992 nor’easter.) Tuesday morning’s storm surge caused moderate flooding, shutting down Route 322 and smaller streets in West Atlantic City, and was just 0.2’ short of the major flooding threshold, according to heraldcourier.com.

As of this writing, the peak storm surge and storm tides had yet to occur along the coasts of Connecticut, eastern New York, Rhode Island, Maine, New Hampshire and Massachusetts; mostly minor coastal flooding is expected, with a few pockets of moderate flooding, due to the relatively rapid motion of the storm across the area. Slow-moving nor’easters are a much bigger coastal flooding threat, since the wind has more time to pile large amounts of water up against the coast. The main concern for coastal flooding will come during the early Tuesday afternoon high tide cycle, when the strong winds of the storm will coincide with high waters from a higher-than-usual high tide, due to the full moon that occurred on Sunday. Wave heights on the ocean waters off the coast of Rhode Island are forecast to range from 11 to 16 feet, causing considerable beach erosion.

According to the NOAA Quicklook Tides and Currents page for Stella, the following approximate peak storm surges (height of the water above normal) and storm tides (height of the water above the high tide mark) were observed on Tuesday morning:

Chesapeake Bay Bridge Tunnel, VA: 2.0’ storm surge, 0.2’ storm tide (peak storm surge occurred near low tide, so a relatively low peak storm tide occurred)
Ocean City Inlet, MD: 1.3’ storm surge, 0.8’ storm tide
Lewes, DE: 2.7’ storm surge, 2.1’ storm tide
Cape May, NJ: 2.5’ storm surge, 2.0’ storm tide
Atlantic City, NJ: 3.4’ storm surge, 3.19’ storm tide (Peak surge occurred near the time of high tide)
Sandy Hook, NJ: 3.5’ storm surge, 2.65’ storm tide
The Battery, New York City, NY: 3.0’ storm surge, 2.57’ storm tide

Figure 4. Freeze warnings (dark purple) occupied a huge swath of the east-central U.S., from southern Missouri to South Carolina, as of Tuesday morning, March 14, 2017. Image credit: NOAA/NWS.

Freeze damage a significant threat this week
A moderately cold air mass for mid-March could have outsized impacts on vegetation in the eastern U.S. this week, given that the cold blast is arriving on the heels of a remarkably warm late winter. Crops and landscapes have been budding, greening, and blossoming several weeks ahead of their usual pace across most of the eastern U.S., so the impact of this week’s expected freeze will be more akin to getting such a cold shot in early April. Temperatures may dip below 25°F as far south as Atlanta on Wednesday morning.

“The greatest risk of the late-season deep freeze in the Southeast will clearly be to the agricultural and farming sector,” said Steve Bowen (Aon Benfield) in an email on Tuesday. “Following such a warm winter, many farms have been reporting earlier-than-normal blooms for some crops (fruit crops in particular). If temperatures fall as much as currently forecast, and stay cold for consecutive days, there could be many millions of dollars of damage from lost crops. The dollar amount will ultimately depend on how cold it actually gets, of course. Even a few degrees in either direction could make a huge difference in financial cost.”

The beloved cherry blossoms of Washington, D.C., were on a record-early pace before this week’s cold and snow. The peak bloom in D.C.’s Tidal Basin is now expected between March 19 and 22, according to the National Park Service—still quite early by historical standards—although the quality of the display we can expect is now in question.

Bob Henson

Figure 5. Temperatures predicted by the 12Z Tuesday run of the GFS model for 8:00 am EDT Wednesday, March 15, 2017. Overnight lows could be several degrees lower than these values. Image credit: tropicaltidbits.com.

Winter Weather

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