How the South Saw More Snow Than Washington D.C. This Winter

You're not alone if you ever feel like there's a dome warding away all signs of snowy weather in your hometown. Lots of meteor... thumbnail 1 summary 3.16.2018  |  01:29
You're not alone if you ever feel like there's a dome warding away all signs of snowy weather in your hometown. Lots of meteorologists and snow lovers take to social media every year to complain about the "snow bubble" or "snow dome" or any of the other frustrated terms we've come up with to complain about getting ripped off in the snow department. Some areas really do just miss out some winters; while snow is on the decline in some areas, the conspicuous lack of snow in one spot compared to nearby counties and states is often a fluke in the grand scheme of things.

One of my favorite weathery complaints is that it seems like thunderstorms go out of their way to miss or hit certain areas. It didn't rain here in my central North Carolina county for a long time—once that streak ended, we got slammed by a parade of severe thunderstorms almost every week, a phenomenon I half-heartedly called #Rockinghaming. I wrote about this perceived thunderstorm bubble over at Mental Floss last year; the phenomenon is so common that there's an XKCD comic strip about it.

The same can apply to snow. Two neighboring towns can see dramatically different snowfall totals from the same storm. The cutoff between feast and famine is so abrupt that it can almost seem like the satellite images and precipitation maps were faked. The fortunes of seasonal snowfall are driven by two major factors: storm tracks and storm characteristics.

Every article written about a nor'easter that doesn't include some variation of the phrase "track is everything" is doing you a disservice. The intricate dance between temperatures, moisture, and lift can be so finicky that a small deviation in a storm's track from what's expected could have a dramatic effect on who sees what.

Nobody knows that better this year than the Washington D.C. metro area. (Sorry to my friends there who find this painful to read.) One look at the seasonal snowfall map shows a glaring omission in areas that decided to participate in the snowfest we've seen south of the Mason-Dixon line this season.

I live just north of Greensboro, N.C., in the small city of Reidsville. We've gotten lucky here this year, measuring about 18 inches of snow this winter. That's well above our average of about seven inches each year. We accomplished this feat across three storms—one in December, one in January, and the storm at the beginning of this week.

Our above-average snowfall wasn't a fluke. Look across almost the entire southern United States and you'll see a trend of unusually high snowfall totals. The accumulating snow even reached the Florida panhandle. Mobile, Alabama, saw just over an inch of snow this winter. Communities south of Corpus Christi, Texas, saw more than half a foot of snow, one of the biggest storms ever recorded in that part of the country.

Washington's National Airport has only recorded 3.7 inches of snow this winter. Dulles Airport off to the west has only seen 6.6 inches of snow, which is around a third of what they see in an average season. Compare that to Baton Rouge, Louisiana—you know, that ol' icebox—where they've seen a cool four inches of snow this season. Jackson, Mississippi has seen nearly six inches of snow, Atlanta nearly five, Virginia's capital city just over ten, and even more than double D.C.'s total down in Raleigh, N.C.

The most noticeable hole in the seasonal snow map above is in the middle of the United States. The lack of snow in the center of the country is a result of the dominant weather patterns across North America this winter. Dallas has only seen a trace of snow so far. Oklahoma City's paltry dusting is far below their seasonal average of seven inches. St. Louis and Kansas City have seen less than half of what they should in a normal winter. Temperatures have been near average for the past couple of months in these areas. However, high pressure has dominated the center of the country for most of the season, deflecting any real chances at winter storms and keeping those that did come through mostly rain or ice.

But why has the atmosphere been such an anti-dendrite in the Mid-Atlantic this year? It's the storm tracks. The storms that rolled toward the East Coast never took the right track to hit D.C. The storm tracks this year have missed the D.C. area to the south, giving towns from Texas to Florida and beyond rare snow days, to the east as nor'easters skirted a little too far off the coast, and to the north in Pennsylvania. The pattern of snowfall totals this year almost resembles a snow shadow with the Appalachian Mountains wringing out all the moisture before any energy can deliver it farther east.

D.C.'s snowy misfortune isn't the whole story. New England has seen its fair share of wintry precipitation this year. But the most recent nor'easter—the third one this month—left a noteworthy lack of snow in a certain spot. Take a look at the pattern of snowfall totals after the nor'easter on March 13:

See that stripe of lower snowfall totals through central Massachusetts? That's not a data error. While the area in question lies in the Connecticut River valley, lower than its surroundings to the east and west, the snow bands really did set up in such a way that towns like Amherst barely had enough to shovel while towns just to the east and west got clocked with more than a foot of snow.

You can see the snow bands clearly in radar images from the event:

The intense bands of snow on the northwest side of a nor'easter form in what's known as the deformation zone. The deformation zone is part of the storm where upper-level winds collide; this zone is the classic "comma head" that makes these storms so beautiful on satellite imagery. These winds fan out laterally and create enhanced lift in the atmosphere. This lift leads to the intense bands of snow that can bury towns in feet of snow.

Sometimes you see one dominant band of snow and sometimes it comes together as multiple strong bands. The storm on March 13 was one of the latter scenarios. The end result was a remarkable hole in snowfall totals in central Massachusetts that only measured a dozen or so miles wide, all while towns on either side get smacked by the intense bands.

There are a few more chances of snow before the warmth finally wins out against the stubborn winter air. It's far too early to tell, but the pattern looks favorable for another East Coast storm, and hey, D.C. could finally get its respectable snow after all. Stranger things have happened.

[Maps: Dennis Mersereau]

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Another Nor'easter Will Dump Snow This Week and Nobody's Forecast Is the Same

Archaeologists will soon be able to tell time by observing the layers in the snowpack that's developed across the northeastern United ... thumbnail 1 summary 3.11.2018  |  22:53
Archaeologists will soon be able to tell time by observing the layers in the snowpack that's developed across the northeastern United States this month. The seeds of yet another nor'easter—the third in the past two weeks, if you're keeping count—are developing over the Ohio Valley and off the coast of the southeast this evening. The newly-minted storm will eventually hook toward New England on Monday night, where some folks may see more than a foot of snow by Wednesday morning.

The current pattern dictating North America's weather over the past few weeks has allowed nor'easters to return with the weekly reliability of a bad sitcom. The storm coming up on Monday and Tuesday will be the third major winter storm in two weeks. This latest storm won't be as widely impactful as the previous two, but the folks who get heavy snow will have plenty of it come Wednesday morning.

Snow will fall in two phases: the first on Sunday night and Monday in the Mid-Atlantic, and the second batch comes while the nor'easter revs up in classic fashion off the coast. The first batch of snow is already falling over the Ohio Valley this evening; some parts of Kentucky are under winter storm warnings for up to eight inches of snow.

How much snow will your town get? Pick a forecast and have fun! The uncertainty in the track of the storm is leading to some interesting and diverging forecasts. Most forecasts for most spots are roughly the same, but you can see the uncertainty in the storm's track based on the forecasts for some cities.

I can understand the frustration of folks who don't follow weather as a hobby as they try to grapple with the idea of forecast uncertainty. My town in North Carolina is currently expecting anywhere between zero and five inches of snow depending on whose forecast you read.

A more southerly track on Sunday night and Monday could expose parts of Virginia and North Carolina to heavier snow and greater accumulations than what's currently forecast. A closer track to the coast on Monday night and Tuesday could bring the heavier snow closer inland, placing more of the Northeast in the path of heavy snow than currently forecast.

Weather Prediction Center:

The latest forecast from the Weather Prediction Center shows a slug of snow starting in Kentucky this evening as the storm makes its way toward the Mid-Atlantic. Rain will change over to snow north of the storm's path, likely subjecting the Appalachians and Piedmont of Virginia and North Carolina to a quick coating on Monday.

Once the nor'easter blooms off the coast on Monday night and Tuesday, heavy snow bands on the northwest side of the storm will rake across New England and drop more than a foot of snow in many spots. Some of these towns still have a foot or more of snow on the ground from last week's storm.

The Weather Channel:


The Weather Channel's forecast is more bullish than the Weather Prediction Center's, showing anywhere from one to five inches of snow across north-central North Carolina, and one to three inches of snow in eastern New Jersey and New York City. Much of coastal New England will see a foot, with some spots coming in with more than a foot-and-a-half.

Despite its taste for internet dramatics and endless reality shows on television, the Atlanta-based weather behemoth has a darn good track record when it comes to forecast accuracy.


The way WeatherBug sees it, a lot of people are going to get 1 to 5 of snow (inches? millimeters? corgi-lengths?) and New England is getting ready to see...dark blue? Where's the dark blue on the scale? What are the units? I have no idea what's going on here, but they're showing a lot (maybe?) in North Carolina and Virginia, and they're giving all the big eastern cities an amount of snow. We're not sure what amount that would be, but it's certainly an amount.



AccuWeather's forecast on Sunday afternoon showed the heaviest snow in the Mid-Atlantic falling in the Appalachian Mountains with lighter totals extending out into the Piedmont toward Richmond, Virginia. Up in New England, the heaviest snow would fall in New Hampshire and Maine.

City Forecasts

Here are some select forecasts for cities on the East Coast as we get closer to the event. This is what you would have seen had you checked the weather around 9:00 PM Eastern on Sunday night.

Some of the forecasts are in line with each other, but they do diverge on amounts. Boston and Providence could see anywhere between 6 and 18 inches of snow depending on whose forecast you look at. New York City could between less than an inch and four inches.

The difference between accumulations is often just splitting hairs—three and five inches of snow are roughly the same in terms of impacts—but a light coating of snow can pose a significant risk in rush hour traffic compared to an inch or two that gives you a chance at some traction. On the other end of the scale, 6-10" is a solid snowstorm but vehicles can easily become stranded once you enter double-digit snows.

Either way, it looks like the big winners (a subjective term, of course) will be the Boston metro area, eastern New Hampshire, and the bulk of populated Maine. When it comes to significant rush hour issues, keep an eye on North Carolina, Virginia, and the Washington D.C. area. It doesn't take much snow to trigger mass panic, and if they're not calling for much tonight and there is accumulating snow tomorrow, lots of people will venture to work only to find themselves driving home in the snow and ice.

[Images: WSV3 / Dennis Mersereau / TWC / WeatherBug / AccuWeather]


Tricky Nor'easter Places Big Cities on Line Between Big Snows or Just a Nuisance

No two snowflakes or nor'easters are exactly alike. Parts of the Northeast will experience a classic winter snowstorm on Wednesday a... thumbnail 1 summary 3.06.2018  |  16:13

No two snowflakes or nor'easters are exactly alike. Parts of the Northeast will experience a classic winter snowstorm on Wednesday and Thursday as a strengthening system along the coast ingests just enough cold air to produce heavy snow from northeastern Maryland to coastal Maine. Some areas will see more than a foot of snow by Thursday.

This nor'easter will be more conventional than last week's windstorm, but it'll hold its own when it comes to impacts. Making the situation worse is that the forecast is both high-stakes—due to the potentially disruptive effects in the big cities—and highly uncertain due to the nature of the storm.

While last week's nor'easter did produce heavy snow across interior parts of the Northeast (including many areas expecting more heavy snow this week), the big story of last week's nor'easter was its relentless winds. Dulles Airport recorded a peak wind gust of 71 MPH during the storm. Many locations in the Mid-Atlantic and Northeast saw wind gusts strong enough to knock out power to more than a million customers, trigger destructive coastal flooding, and the gusts even led to the demise of one of Interstate 95's most memorable...landmarks.

The headline for this storm will be heavy snow. Current forecasts show the nor'easter ramping up off the Delmarva Peninsula on Tuesday night. The storm will quickly get its act together as an upper-level trough and a jet streak (an area of stronger winds within the jet stream) move off the coast and align to help the storm quickly strengthen.

Here's what you can expect:
  • Heavy snow along and west of Interstate 95, with a sharp cutoff in totals.
  • Flight/train cancellations and roads nearly impassable in the heaviest bands.
  • Heavy rain at the coast possibly switching over to snow late in the storm.
  • The weight of the snow and gusty winds will stress trees that took a beating last week, leading to the potential for more power outages and damage.

A complicated forecast 


The most important thing to know about nor'easters is that the track is crucial in who sees what. A tiny nudge to the east or the west in a storm's path could dramatically change a town's snowy fortunes. Too close to land and the heavy snow stays inland and areas closer to the coast are a wintry mix or cold, dreary rain. Too far from shore and the snow stays along the immediate coast. 

This atmospheric high-wire act often leaves the megalopolis—the string of cities along Interstate 95 between Washington and Boston—teetering between precipitation types. That's stressful to deal with when millions of people are expecting perfect forecasts and you may not be able to tell them with confidence what kind of precipitation they'll see and how much of it they can expect.

Wednesday's storm is forecast to ride right along the coast, which pushes the heavy snow inland and keeps the immediate coast rain for most of the storm. The likely track of the storm will put the deepest accumulations just to the west of I-95, but golly is it going to be a close one for cities like Philadelphia, New York, and Boston.

The current forecast from the Weather Prediction Center (mapped by yours truly above) shows that the agency's most likely scenario (50th percentile) was that the heaviest snow would fall just a few miles west of the major cities from Philly to Boston. This is likely going to be a big storm for interior areas, with much of upstate New York and New England seeing a foot or more by the end of the storm.

There's going to be a sharp gradient in snowfall totals wherever the heaviest bands set up. Neighboring counties (even neighboring towns) could see double-digit differences in accumulation.

Now, that's just the WPC's 50th-percentile (most likely) forecast from early this morning. The situation gets much more interesting if you go a step lower and start reading forecasts from individual NWS offices, each of which has their own local experts that produce their own forecasts.

The official forecast from NWS New York (pictured above) shows the heavy snow falling closer to the coast, plastering New York City with more than half a foot of snow and its far northern suburbs coming in with more than a foot. That's a pretty big difference from the most likely WPC forecast issued this morning.

It's a similar situation up in Boston where the forecast is shifting by leaps and bounds depending on what town you're driving through. The original forecast issued this morning called for up to 8" of snow in Boston proper while towns like Taunton and Foxborough, separated by 14 miles, had a nine-inch spread in snow totals between them.

The latest forecast from NWS Boston shows the rain/snow line pushed farther inland, keeping Boston's snow on the inconvenient side and putting the stress of wondering if you'll get plastered or annoyed squarely on inland towns. An eastward jog in the storm's track could bring the forecast for heavier snows closer to the coast again.

Why so much uncertainty?

The track of the storm is responsible for all of this uncertainty. The storm will be close enough to the coast that just a tiny intrusion of warm air at or above the surface could provide towns close to the shore with much lower snowfall totals than they would see if the storm scooted a bit farther off the coast and the atmosphere was uniformly subfreezing from top to bottom.

Here's what the WPC had to say in their heavy snow discussion on Tuesday morning:


And this is what NWS New York said in its forecast discussion at 12:54 PM on Tuesday:

Precipitation will be light to start, and this light intensity may allow parts of the New York City metro area to start off as rain, but as the precipitation becomes steadier and heavier, cooling the column, a change over to all snow is expected late tonight.

The latter discussion refers to a process known as evaporative cooling—liquid absorbs latent heat when it evaporates, which helps cool the air. You've probably heard the term in the context of air conditioners or even reading about how microbursts form, but evaporative cooling can help change rain over to snow in winter storms. You might see talk on social media about winter storm "producing its own cold air," and this is the process they're usually hoping will happen.

Prepare for the worst and hope for the best.

It can be frustrating to hear something like this when we live in an era where we can predict the weather with such accuracy and precision, but some things really do come down to waiting and watching. Local forecasters expect the heaviest snow to develop right over the big cities and unload off to the west, but the storm's finicky track and unexpected intrusions of warm air above the surface can change things in a hurry.

The best thing to do right now is to expect the worst and hope for the best. It's going to be a close one no matter which way the precipitation falls. It's the wonder of geography and meteorology that some of the country's biggest cities fall right where the rain/snow line usually sets up shop.

Watch out for power outages.

The term "heavy snow" doesn't only apply to how fast it falls—for many, it's going to be a wet snow that will be hard to shovel and even harder on trees and power lines. The weight of the snow and additional force of more gusty winds will add stress to trees that were stressed-out last week (weren't we all) in the gusty winds. This could lead to more power outages, which is something you don't want when it's going to drop down into the 20s at night.

Just like last week, make sure you're prepared to deal with power outages. Keep your phones and devices charged and keep a few actual flashlights (not just the feature on your cell phone) juiced up and ready to go just in case the lights go out.

[Satellite Image: NOAA | WPC Map: Author | NWS Maps: NWS New York / NWS Boston]

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An Intense Windstorm Will Rake the East Coast on Friday and Saturday

The bark is sometimes worse than the bite in nor'easters. The nor'easter set to form off the East Coast tonight will not be o... thumbnail 1 summary 3.01.2018  |  20:42

The bark is sometimes worse than the bite in nor'easters. The nor'easter set to form off the East Coast tonight will not be one of those storms. If you don't know the storm is coming, you'll hear it soon enough. This storm will crank out some strong winds across the Ohio Valley, Mid-Atlantic, and the Northeast, with gusts possibly reaching 70 mph in spots between Thursday night and Saturday afternoon.

This will be a large storm with widespread effects. We'll see a little bit of everything from this system: snow, rain, flooding, wind, you name it. But even though it's raining just about everywhere on the East Coast right now and some folks will see more than a foot of heavy, wet snow, it's the wind that's going to cause the most problems.

Wind advisories are in effect from central Alabama to the coast of Maine and high wind warnings are in effect from western North Carolina through Massachusetts. Winds could gust higher than 60 MPH in the warning areas, with a particular focus on the Appalachian Mountains, the Washington/Baltimore metro areas, and the New England coast.

Surface analysis at 3:00 PM EST March 1, 2018.
The winds are already kicking in the Ohio Valley. Cincinnati Airport (KCVG) measured sustained winds around 30 MPH and gusts near 45 MPH around 3:00 PM Eastern on Thursday. The gusty winds will continue moving east and strengthen on Thursday night as the low-pressure system makes its way toward the coast and reorganizes into the impending nor'easter.

Why is it going to get so windy? The first issue is that the nor'easter will undergo bombogenesis over the next 24 hours. Bombogenesis describes the rapid deepening of a low-pressure systems minimum air pressure. Forecasts show the low's central pressure dipping below 976 mb by Friday morning. That's a decent pressure for a nor'easter—even deeper than some weak hurricanes.

Unlike the structure of a tropical storm or hurricane, which keeps the bulk of its energy bottled-up in one small part of the storm, extratropical cyclones like nor'easters spread out their energy. This storm isn't going to be a problem for one or two states. It's a problem for almost a quarter of the country.

The storm's forecast strength alone is impressive enough, but a strong high-pressure system will build over the Midwest at the same time as the nor'easter strengthens. This combination of a strong low and a strong high in relatively close quarters will result in a tight pressure gradient that causes winds to crank up for a period on Friday and Saturday.

The above chart shows what the GFS model thinks winds (in kts) will look like a few thousand feet above the ground around 7:00 AM Eastern on Friday morning. The wind is going to be ripping just above the surface over the Mid-Atlantic, and it won't take much to translate that energy down to the ground.

The core of the intense winds will shift its focus to New England on Friday evening and Saturday.

The Crayola explosion above is the National Weather Service's forecast wind gusts for 5:00 PM EST on Friday, March 2, 2018. (The values on the map are in MPH even though the caption says KTS.) It's going to be so windy in the Mid-Atlantic and Northeast that smaller folks and kids may have trouble walking around outdoors.

Wind damage is likely from this storm. Downed trees will cause damage to power lines, buildings, and vehicles. Debris will make some roads impassable for a time during the storm. Recent (and ongoing) rainfall has softened the soil and will make trees more susceptible to falling over. Widespread power outages are likely in areas expecting the highest winds.

A large number of flights will be cancelled—causing a ripple effect of cancellations and delays nationwide—as winds will exceed maximum levels that allow for safe flight at many of the country's eastern hubs.

Another ugly side effect of this wind is that it will send a storm surge into the coast. The surge will act much like it does during a tropical cyclone—the strong winds will push up to three feet of seawater into coastal communities at high tide from North Carolina to Maine, with a surge of up to five feet possible in parts of Massachusetts where the coast is perpendicular to the direction of the strongest winds. This will lead to flooding in communities right on the shore.

What can you do to prepare?
  • Charge your mobile devices! Keep your cell phone as close to a full charge as possible. If you have a portable power/battery pack for your phone, keep that charged, too. Power outages are no fun, but they're even less fun if you can't communicate with anyone.
  • Canned food and bottled water is a cliché, but it's really useful if you can't cook. Bottled water is also good to have in the unlikely event municipal water is unsafe to drink or your well pump goes down. (A boil water advisory is useless if you have no way to boil the water.)
  • If you have furniture, pottery, or knick knacks on your deck, balcony, or porch that you want to keep on your deck, balcony, or porch, don't forget to secure them or bring them inside tonight before you go to sleep. The wind could knock them around and break them—or worse, break something else.
  • Try to avoid walking or parking beneath tall trees or trees with limbs hanging over sidewalks, parking spots, and roadways.
  • Use extra care walking around in downtown areas. Debris that blows off of tall buildings, balconies, or construction sites can hit the street at a dangerous velocity.
Aside from the winds, heavy rain and snow will be a lesser threat on Friday and Saturday. A few inches of rain could push streams above their banks and overwhelm drainage systems, covering roadways and possibly threatening buildings in flood zones.

The storm will produce a heavy, sticky snow in the Northeast from Pennsylvania northward to the Canadian border. Forecasters expect up to a foot of snow in much of upstate New York, with totals exceeding one foot in western New York and in the Catskills. The combination of wet snow and high winds could increase the risk for downed trees and power outages in areas that receive significant accumulations.

[Images: Dennis Mersereau | College of DuPage | Tropical Tidbits | NWS]

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