Video posted to social media shows snow beginning to fall in New York City, ahead of what is expected to be a blizzard in the Northeast. (The Washington Post)

Forecast snow totals:

  • New York City: 18 to 24 inches in Manhattan, Staten Island, 24 to 36 inches elsewhere
  • Boston: 24 to 36 inches
  • Providence: 24 to 36 inches
  • Philadelphia: 10 to 14 inches

Live: News updates on the Northeast blizzard

Update at 9:50 p.m.: A big-picture update to round out the evening.

Heavy snow is falling from New York City east to Cape Cod, and north into Boston and southeast New Hampshire. Embedded in this shield of snow are bands with rates of 1 to 2 inches per hour.

Snow combined with with rapidly climbing wind gusts will lead to whiteout conditions, and travel bans are in effect across much of the area. Though the travel ban on Long Island doesn’t go into effect until 11 p.m., the Weather Service is strongly discouraging travel there.

We will continue our Northeast blizzard coverage on Tuesday morning, but in the meantime you can follow the Northeast blizzard live blog for updates overnight.


Radar at 9:45 p.m. (Weather Underground)

Update at 9:30 p.m.: Wind gusts across southern New England are climbing rapidly now — 35 to 50 mph off the coast of Massachusetts, and 35 to 45 mph on Long Island.


Wind gusts and direction across southern New England and Long Island at 9:30 p.m. (NWS)

Update at 9:05 p.m.: Wind speed is increasing as the storm deepens and its center moves north toward New England. Wind gusts in Provincetown, Mass., have climbed to 40 mph, and 45 mph near Nantucket.

Multiple bands of heavy snow are tracking west across southern New England and Long Island, with snowfall rates of 1 to 2 inches per hour.

New York Gov. Cuomo issued a travel ban beginning at 11 p.m. tonight on Long Island, but that seems to be coming two hours too late — the Weather Service is advising against travel now as this heavy band sweeps west across the island.

The high resolution HRRR model gives us an idea of how the storm might evolve through 10 a.m. Tuesday. Black lines indicate pressure, and colors indicate wind speed.


HRRR pressure and 10-meter wind forecast through 10 a.m. Tuesday. (weatherbell.com)

Update at 7:46 p.m.: That heavy snow band we’ve been watching for the past couple of hours has made its way north to coastal Rhode Island and the Cape. It also extends to eastern Long Island, where conditions are deteriorating.

The National Weather Service expects visibility to drop to less than 1/2 a mile in the band (shown below in dark blue), with a quick accumulation of 2 to 3 inches.


Radar at 7:42 p.m. (RadarScope)

I couldn’t not share this one. Stepping out in Reading, Pa.!

Update at 7:20 p.m.: Snow totals so far around New York City.

Queens

Rego Park — 4.8 inches
Bayside — 4.0
French Meadows — 3.0 inches
La Guardia — 2.5 inches

Manhattan

Central Park — 4.3 inches

Nassau County

Bethpage — 4.0 inches
Hicksville — 4.0 inches
Plainview — 4.0 inches
Bellerose — 3.4 inches
Malverne — 3.1 inches


Snow totals around New York City through 5:30 p.m. (NWS)

Update at 6:45 p.m.: The Storm Prediction Center has issued a mesoscale discussion on the potential for heavy snow in southern New England. They expect snowfall rates of at least one inch per hour to begin between 8 and 9 p.m. along the southern New England coast and Long Island.

They continue [I’m paraphrasing], “Initially, snowfall rates around 1 inch per hour will be confined to the immediate coastal areas of Rhode Island and adjacent portions of Massachusetts, but are forecast to develop inland during the 8 to 10 p.m. period. It is likely the heavier rates — 2 inches per hour or greater — will occur beyond 11 p.m.”

A mesoscale discussion for heavy snow has been issued by the Storm Prediction Center. (NWS SPC)
A mesoscale discussion for heavy snow has been issued by the Storm Prediction Center. (NWS SPC)

The Weather Channel’s Jim Cantore is in Boston for the storm, and shared this image of the organization’s version of the WRF model, which also shows eastern Massachusetts, including Boston, as the maximum region of potential snowfall.

Update at 5:42 p.m.: Light snow has spread across eastern Connecticut and eastern Massachusetts A band of intense snowfall (dark blue) can be seen making its way north, and has already passed over Nantucket — this will likely be the first intense band of many, with severely reduced visibility. Wind gusts on Nantucket have peaked at 35 mph so far, with higher gusts to come.


(RadarScope)

Update at 5:05 p.m.: Strong words from the National Weather Service in New York. “It should be a raging blizzard at 6 a.m. … with heavy snow … damaging winds and whiteout conditions across most of the area.” They also caution that given the model guidance, there is “definite 3 foot potential” in the New York City area, but again, where exactly those totals will end up falling remains to be seen.

Update at 4:54 p.m.: Bands of light to moderate snow are moving across eastern Massachusetts, and conditions will continue to deteriorate. An area of very heavy snow can be seen on radar off the coast, moving north through Nantucket Sound.


(RadarScope)

Update at 4:19 p.m.: After a few hours of persistent moderate snow, roads are getting messy in New York. Radar indicates that conditions will lighten up off and on for at least the next couple of hours. This period of lighter snow is not unexpected ahead of the most intense conditions — snowfall rates of 2 to 4 inches per hour, wind gusts to 55 mph in the city and 70 mph on Long Island — which will move in later tonight.

Clairement, il fait pas terrible. #manhattan #snow #storm

A photo posted by David Cyngiser (@cyngi) on

The high-resolution HRRR model gives is a feeling for conditions at 5 a.m. Tuesday. By then, the model suggests blizzard conditions will have spread across eastern Massachusetts. The question remains, though — exactly how far west will the storm track, and therefore how much snow will New York City see? This model suggests that, at least through 5 a.m., N.Y.C. will be on the edge of the snow shield.


Forecast radar for 5 a.m. Tuesday from the HRRR model. (weatherbell.com)

Visibility was down to 1/4 of a mile in Central Park about around 3 p.m.:

See you guys in a few weeks.

A photo posted by Scott Neff (@scott_neff) on

But the snow lightened up by 4 p.m. across much of Manhattan:

It's snowing!!!

A photo posted by Leo Bieber (@leobieberphoto) on

Update at 3:40 p.m.: The 1 p.m. run of the NAM model has come in, and once again it targets the New York City area with an incredible amount of snow. This forecast would dump 20 to 30 inches of snow across eastern New Jersey, New York City metro, and Long Island, and as much as 30 inches in eastern Massachusetts.


Snowfall forecast from the afternoon run of the NAM model. (weatherbell.com)

Update at 3:17 p.m.: Snow has pushed north through Connecticut and Rhode Island, and is approaching Boston, so if you’re planning on heading home before the snow starts in Beantown, now is your last chance to do so.

Heavy snow has been reported in Central Park, and visibility is down to 1/4 of a mile.


(Weather Underground)

We’re kind of surprised by the number of people still out on their bikes this afternoon in New York. This cyclist is still out delivering food:

Blizzard is beginning, yet these bike delivery guys are still bringing people their food. Definition of HTFU.

A photo posted by PhilPMueller (@philpmueller) on

This pup is named Leela, and she’s having a great time in a snowy Central Park:

Leela having a amazing time! #corgi #snowday #playinginthesnow #centralpark #whiteday

A photo posted by My Great Paws (@mygreatpaws) on

Time to go home? #juno #nyc

A video posted by Andrew Weir (@weirgrammin) on

Let the snowmageddon begin! #nyc #snowmaggedon

A photo posted by Gustavo Jesus (@gugliz) on

Update at 2:52 p.m.: This afternoon, the National Weather Service is flying a Hurricane Hunter through the storm to improve forecasts. The data collected by the flight will be fed into the model forecasts that initialize at 7 p.m.ET.

“The recon flights are part of our long standing Atlantic Winter Storm Reconnaissance program,” said Chris Vaccaro, a spokesperson for the National Weather Service. “We also flew a flight last night over the Gulf of Mexico to try and sample sensitivity to improve the fcst of the nor’easter.  Last night, 6 dropsondes over the Gulf of mexico were available for 26/00Z NAM ingest.  9 dropsondes were available for the 26/00Z GFS ingest.”

Governor Cuomo has said that assuming nothing changes with the storm (and we don’t really think it will), there will be a travel ban on Long Island starting at 11 p.m. This might be a little late for the onset of the most hazardous impacts.

Update at 2:05 p.m.: Moderate snow is falling across New York City and Long Island, snarling traffic. It looks like even the treated roads are becoming snow-coated at this point. Moisture is really surging into the Northeast now, and conditions will continue to deteriorate as the storm deepens and pushes north.


(Weather Underground)

Manhattan Bridge 1:52 #blizzardof2015

A video posted by Frank Eaton (@mrfrankeaton) on

#Snowmageddon #centralpark #gotham #sheepmeadow #newyorkcity

A photo posted by Daniel James Shigo (@saengerman) on

Part 1. #blizzard

A photo posted by Jeffrey Betts (@jeffreybetts) on

Update at 1:26 p.m.: The morning run of the European model has come in, and it shows a few differences from previous runs, though the overall message remains the same.

The biggest change — and of course, this is really pulling hairs at this point — is the decrease in moisture over New York City, which would mean lower snow fall totals there. The Euro *only* pumps out 1-1.5 inches of liquid over New York City. I say *only* because in any other snow storm, that would be a very large amount of precipitation. But this storm is a bit superlative to start with.


Total liquid precipitation forecast through Wednesday from the morning run of the European model. (weatherbell.com)

To understand what this forecast means for snow, we need to talk about snow-to-liquid equivalent. This model run is saying that when you take the snow that falls over New York City and melt it down, you’ll get 1 inch of water. But it’s going to fall as light, fluffy snow, which is where it gets a little tricky. A typical snow-to-liquid ratio is 10-to-1, or 10 inches of snow for every 1 inch of liquid. But in colder storms — like this one — the ratio goes up to as much as 1-to-15, or up to 15 inches of snow.

Again, the Euro model really pumps out the moisture over eastern Massachusetts — 3 to 3.5 inches of liquid, which would mean anywhere from 30 to 50 inches of snow, depending on the actual ratio.

Here’s what the above liquid moisture map would end up looking like in snow inches with a 10-to-1 ratio:


Snowfall accumulation through Wednesday from the Monday morning run of the European model, with a 10:1 ratio. (weatherbell.com)

Update at 1 p.m.: The National Weather Service has increased their “most likely” snow accumulation around the New York City area, and across Brooklyn, Queens, the Bronx, Long Island and southern Connecticut. They are back to 24 to 36 inches in these areas, but Manhattan and Staten Island remains in an 18 to 24 inch forecast.

Again, New York’s final totals will depend heavily on the exact track of the nor’easter, as well as where the heaviest snow bands set up.


“Most likely” snowfall forecast for the N.Y.C. metro area, Long Island, and southern Connecticut as of 1 p.m. ET on Monday. (NWS New York)

Update at 12:40 p.m.: A blast from the past! This photo was taken in Manhattan on Feb. 12, 2006, after 26.9 inches of snow fell — the snowiest storm on record for New York City. The the photographer writes that there is, in fact, a car under there. Thanks to Shaun Tanner at Weather Underground for *digging* that one up!


A girl leans against a snow-covered car in Manhattan on Feb. 12, 2006, after 26.9 inches of snow fell. (singwood via Weather Underground)

Update at 12:28 p.m.: Here at the Capital Weather Gang, we talk a lot about our confidence in the forecast. After all, a big snow forecast means very little if you’re completely uncertain about it. So how confident is the National Weather Service in their snowfall forecast? They seem fairly confident, given their forecast probabilities.

Around Boston, the NWS is forecasting a 100 percent probability that most areas in eastern Massachusetts will see at least 12 inches of snow, and a 90 percent probability that they will see at least 18 inches, as shown in the graphic below:


Probability of areas seen at least 18 inches of snow through Wednesday morning. (NWS Boston)

Given the uncertainty between model forecasts, the Weather Service in New York City a little less sure of the forecast, but not by much. The NWS is giving areas around New York, Long Island, and southern Connecticut an 80 to 90 percent chance of seeing at least 12 inches of snow.


Probability of areas seen at least 12 inches of snow through Wednesday morning. (NWS New York)

These differences in forecast certainty stems from the disagreement in the models on the storm’s final track, it’s forward speed, and thereby how much moisture will fall in the New York area. The models are still showing a lot of “spread” across the region — meaning some are showing low snow accumulation (10 to 15 inches) and some are showing very high accumulation (20 to 30 inches).

The Weather Service takes all of this into account for their final forecast (still 18 to 24 inches across the region), but has weighted it more toward the higher forecasts given that a few of the models are coming into agreement in that range. The tricky part of these coastal storms is that the highest snowfall totals will occur where the heaviest snow bands set up — and it’s very difficult to forecast where that might be, even just 12 hours before the onset of the biggest impacts.

The New York City way of starting a new semester😭

A photo posted by Emily Wong (@eeemmiilyyy) on

Snowy #williamsburg #brooklyn

A photo posted by @ernestoelizondo on

Update at 11:45 a.m.: The morning run of the GFS is in, and it’s showing less than 10 inches of snow for the N.Y.C. metro, and around 20 inches in southeast Massachusetts. This forecast is a few inches down from the previous run of the model. The GFS has tended to be on the low end of the snowfall forecasts since this storm came into focus over the weekend.

The difference between the GFS model and the NAM rests in the track and timing forecast. The GFS model tracks the storm a little bit further to the east, which means the heavier snow will fall over the water. The NAM is also slower with the storm, which means the duration of snow over land would be longer, leading to higher accumulation.

You’ll often hear that the “European model is better than the GFS,” but I will say that the GFS has been performing well this winter, so it’s probably not wise to discount the idea of these lower accumulations. That being said, we’re talking about a foot of snow as the “low end” of the forecast range — this will likely be a high accumulation storm in any case.


Snowfall forecast from the morning run of the GFS model. (tropicaltidbits.com)

People in Connecticut are taking no risks this afternoon. The bottled water shelves are barren in Bristol.

Update at 11:15 a.m.: Let’s talk details about timing — when will the worst conditions occur, and how long will they last?

Morning model runs (GFS, NAM) are suggesting the worst impacts (ie. high snowfall rates and white-out conditions) will spread from N.Y.C. to Boston starting this evening, peaking between Midnight and 8 a.m. Tuesday morning, and then gradually letting up after that.

However, snow is already pushing north from Philadelphia to Connecticut and Rhode Island at this point, and snow (though not intense, white-out condition snow) will linger in these areas through Tuesday afternoon.


Radar over the Northeast at 11:15 a.m. (Weather Underground)

Greg Carbin, the warning coordination meteorologist at the Storm Prediction Center, shared the “duration in blizzard conditions” forecast from the NAM model. The light and dark purple areas span nine to 16 hours, and the light blue represents a widespread swath of six to nine hours in blizzard conditions. This includes locations from New York City through Connecticut and eastern Massachusetts.

Sixteen hours of solid blizzard conditions is pretty mind-boggling, and we need to take that forecast with a grain of salt. In the areas hardest hit by the storm, six to nine hours of blizzard conditions seems more likely, and many areas will probably see on-and-off white-outs, instead of a solid duration.

But like Greg says, it will be interesting to compare this forecast to what we see on the ground.

Update at 10:40 a.m.: WBZ-Boston meteorologist Eric Fisher suggests not reading too much into the forecast snow totals, and we agree with him. The range of potential snow is large, and the difference between 2 and 3 feet of snow, in terms of impact, is negligible, particularly in the Boston area.

The take-home message for this nor’easter forecast is the high snowfall rates in combination with strong winds, which will lead to white-out conditions. Power outages will also be a guarantee in some locations as 50 to even 80 mph gusts bring down power lines.

Update at 10:10 a.m.: A new forecast model run has come in — the morning run of the NAM — increasing the snowfall totals for New York City. This back-and-forth forecast for the southern part of the storm is not surprising. It’s still very uncertain where the heaviest snow bands will set up, and each model run is fed with new, current data to try and guess where that might be.

This forecast maxes out the StormVista color scale at 30 inches over Long Island, Connecticut, and a portion of southern New Hampshire and north-central Massachusetts. There’s no change to the National Weather Service snow forecast at this time — they are still going with 18 to 24 inches.


Snow total forecast from Monday morning’s run of the NAM forecast model. (stormvistawxmodels.com)

A travel ban is in effect for the entire state of Connecticut starting at 9 p.m. tonight.

Original post


The snowiest storm of the season is ramping up on the East Coast Monday morning. (earth.nullschool.net)

The snow is already falling in the Northeast on Monday morning — just the beginning of a multi-day nor’easter that could become one of the snowiest on record for the region.

One to 3 feet of snow, damaging winds, and white-out conditions are expected. Thousands of flights have been canceled. The National Weather Service is calling it a “crippling and potentially historic blizzard.”

D.C. live updates: Snow, rain, and wintry mix today, areas of snow tonight

The entire Northeast coast, from New Jersey to Maine, is covered in blizzard and winter storm warnings on Monday in anticipation of what could be the strongest East Coast winter storm in at least a decade. Over 29 million people are under a blizzard warning, and 14 million people are under a winter storm warning. From New York City to Boston, the worst impacts — heaviest snow, strongest winds – will hit between Monday night and Tuesday afternoon.

Forecast snow totals:

  • New York City: 18 to 24 inches
  • Boston: 24 to 36 inches
  • Providence: 24 to 36 inches
  • Philadelphia: 10 to 14 inches

The storm’s final track will determine who sees the most snow this week. Though forecasts have been wavering on the snow totals in New York City, Boston has consistently been in the snowy bull’s-eye of this nor’easter. On Monday morning, the National Weather Service was forecasting 24 to 36 inches of snow for almost all of eastern Massachusetts, including Boston. Those forecast totals stretch south into Rhode Island and Connecticut.


“Most likely” snow accumulation forecast. (NWS Boston)

Around New York, the snow forecast has been reduced since Sunday night — though the difference in impact could prove to be negligible. The Weather Service’s “most likely” snow forecast for the New York City metro area, Long Island and coastal Connecticut is 18 to 24 inches.


“Most likely” snow accumulation forecast. (NWS)

New York City’s snowiest storm on record was Feb. 11-12, 2006, mostly on a Sunday, when 26.9 inches fell. Boston’s snowiest is Feb. 17-18, 2003, with 27.6 inches. Snowfall totals could approach the record in Boston, and the winter storm could be among the highest-impact for the city.

Wind gusts are expected to peak at 55 mph across parts of New York City and Long Island, and up to 75 mph in eastern Massachusetts. These wind speeds in combination with snowfall rates of 2 to 4 inches per hour will undoubtedly reduce visibility to near-zero at times, making travel impossible.

(NWS New York City)
(NWS New York City)

The storm’s strong winds will do more than cause blizzard conditions across the Northeast. A coastal flood warning is in effect for the entire shoreline of Massachusetts, for moderate to isolated areas of major flooding. The Weather Service writes that “flooding of vulnerable shore roads and basements expected … some structural damage is likely in most vulnerable locations. Severe beach erosion is expected …”

The Weather Channel’s Jonathan Erdman says that this was the strongest wording he’s seen in a coastal flood warning, outside of hurricane storm surge events.