I wanted to take a closer look at some of the historic evolution and power of the Blizzard of 2013 and show everyone some of the amazing graphics that came out of the system. Apart from being the worst storm in 125 years for much of Connecticut the Blizzard of 2013 also featured some of the most intense snowfall ever seen. Disclaimer - I am not a meteorologist, but I am a weather nerd and have been since I was a child. I will make a preemptive apology for the oversimplification of some of this and my lack of understanding of some of the dynamic physics behind all of it. Thankfully the public is becoming more educated over time and on-air meteorologists are putting forth more information (such as explanations of certain models) for everyone to better understand how weather works. But it is still such an incredibly deep and complex field still fraught with uncertainties in our understanding overall and subject to the chaotic forces of the atmosphere with so many processes occurring simultaneously. When it comes to forecasting even the smallest change here or there can mean wildly different outcomes even for storms in the short-range.
The European (ECMFW or "Euro") model was able to lock on to a solution of a potentially major storm four days away indicating that much of southern New England would be buried in perhaps feet of snow. The Euro runs twice a day and is a long-range model. This graphic and the rest I will post are all free and publicly available.
The image is a four-panel chart from the 12z (noon) run of the Euro on Tuesday, February 5. According to this Boston was the epicenter and would see historic totals while a sloppy mess would greet New York City, progressively worsening as you moved towards the east. The low bombs out to get the pressure down to the 980s (measurement in millibars) creating a heck of a lot of wind and precipitation. What is most fascinating about the above image is how well it depicts the deformation banding that would occur right over us as you can see in the lower left panel of the 700MB level. Think of that as almost a severe thunderstorm along a cold front in the summer with all areas under the front receiving rain but some seeing convection triggering thunderstorms that result in heavier amounts. Areas in eastern Connecticut did actually have thundersnow and many reported seeing cloud to ground lightning strikes! There was even talk of putting up a severe thunderstorm warning late Friday night because of its intensity.
You cannot look at a model and say that it is going to happen because no result will ever be exact. Meteorologists use their knowledge to interpret and analyze the results of these essentially dozens of computer simulations that bring in different data and information and hold different biases and shortcomings to create forecasts. Nevertheless, with the European model having the best verification scores of any for the long-range, it is taken very seriously. That Euro run ended up being close to how things looked early Saturday morning with the only differences being a colder system that had heavier precipitation with more energy across the center of Connecticut. Suffice it to say it caught everyone's attention and caused me to start putting the word out on a potential monster. The ensuing runs only left us with even more snow.
On February 6 one of the most legendary winter storm analysts in the world, Paul Kocin, wrote a sensational analysis of what could happen for the National Weather Service's Hydrometerological Prediction Center. In part he wrote:
" THE 12Z RUNS INCREASINGLY POINT TO CENTRAL AND EASTERN NEW ENGLAND RECEIVING THE BRUNT OF THE STORM AS THE CENTRAL PRESSURES OF THE LOW FALL TO THE 970S TO LOW 980S WITHIN THE 12Z RUNS. THE LIKELIHOOD OF GREATER THAN 12 INCHES OF SNOW IS HIGH ACROSS MUCH OF THE AREA AND AMOUNTS GREATER THAN 24 INCHES ARE POSSIBLE...ESPECIALLY ACROSS EASTERN NEW ENGLAND. MIXED PRECIPITATION MAY HOLD DOWN AMOUNTS ACROSS SOUTHEAST MASSACHUSETTS AND ALONG THE IMMEDIATE SOUTHERN NEW ENGLAND COAST. THE GREATEST AMOUNTS ARE FOUND JUST NORTHWEST FROM WHERE THE CYCLONE DECELERATES AND EVEN MAY MAKE A BIT OF A LOOP AROUND ITSELF ON SATURDAY. THE 00Z AND 12Z ECMWF ALSO SHOW THE LOW THEN MAKING A SLOW SOUTHEASTWARD TO EASTWARD MOTION BEFORE PULLING NORTHEASTWARD INTO THE ATLANTIC. THIS IS THE SAME KIND OF BEHAVIOR EXHIBITED BY SOME OF THE MOST INTENSE STORMS...SUCH AS THE MORE RECENT BLIZZARD OF 2005/APRIL FOOLS BLIZZARD OF 1997...THAT THIS STORM MAY ALSO EXHIBIT."
At that point it was thought the storm could rival some of the greatest ever but would not take its eventual place near the top. The North American Model (NAM) that runs out to 84 hours four times a day insisted during several runs that we would see enormous amounts of precipitation. It yielded 73.3 inches of snow for Boston and about 97 inches in Maine at one point. It is notorious for exaggerating actual totals and this provided some good laughs throughout the day. Still, the situation kept changing and on the 12z Euro run on Thursday, February 7, we saw how much of the area could get over two feet of snow as it came in with more precipitation and was even colder. Bridgeport's climate station (at the Stratford airport) would have received 2.84 inches of water on that run, 100% of it being snow, and conservative estimates would make that nearly 30 inches.
Let's take a look at the conditions on February 7 to better see how this beast came together. Below is a surface weather map with stations and their observations plotted in that shows the conditions at 7AM that day.
There are a few components to note on that map. First take a look at Canada and see the high pressure extending west to east over us helping keep cold air in place. Next take a look south of it and see the low near the Great Lakes and associated precipitation. Finally you can see a low in the Gulf of Mexico hugging the coastline with its precipitation. These northern and southern lows would end up phasing at just the right time and forming a tremendously powerful low off the North Carolina coast that would move northeast and strengthen as it did. The Euro had been able to accurately predict this happening days before.
As we moved into Friday, February 8, the NAM continued to tell us there would be an insane amount of water falling across some parts of the area. It became more realistic (but still seeming like a fantasy) with amounts topping out around four inches and if even half of that actually fell it would be around two feet of snow. The Euro was trending colder and wetter with possibly over 30 inches of snow in some areas, and the fact the NAM continued with this the day before and of the storm made many people wonder if it would somehow produce such an area of three or more feet. The Global Forecast System (GFS), America's long-range model, had trouble with the storm nearly until the end. At the very least it did keep insisting it would be further east and keep areas like New York City outside of huge totals, and in this way it was correct.
It also became obvious the power of the storm would create very strong winds with enormous differences in pressure powering air over the land and sea. As one nears the center of low pressure the winds increase so in this case Connecticut would be spared the worst winds that later hammered Massachusetts. Blizzard warnings were hoisted for all of southern New England. These are issued when it is expected snow will be heavy and reduce visibility below one quarter mile for three hours or more, and when the winds are expected to be sustained at 35 MPH or more. It is not, as goes the common misconception, a warning for an amount of snowfall.
Here is the same surface map from above at 7AM on Friday, February 8.
By this point the coastal low has formed and precipitation was breaking out to the northeast. Connecticut began to see snow near dawn along the coast, right on schedule, light to moderate in intensity and accumulating slowly throughout the morning into the early afternoon. Considering the amount of lead time ahead of the system, with it being on the minds of the public for days unlike many past surprise historic storms, and its slow start, a lot of folks seem to have thought it was a bust early Friday. It was obvious this was not the case as radar images like the following showed an incredible storm deepening rapidly and exploding with precipitation as it moved northeast. Phasing had occurred and this massive comma head had formed starting to add to early totals while the rest of the northern energy raced in to meet it.
However, I did think that most of Connecticut, especially western areas, would be barely missing out on historic storm totals and end up more along the lines up 18 or 20 inches at most. I believed this would be a major storm, but not something none of us had ever seen. Even on that radar image I thought it would pivot just a little to our east, putting the heavy banding across Boston and northeast Connecticut, sliding into Rhode Island and Massachusetts. By late afternoon I was proved wrong as it came in a little more west than expected and precipitation extender further northwest than anticipated (even though this is often the case with such systems). We were looking at a long night and this image from the first Mesoscale Discussion from the National Weather Service's Storm Prediction Center concerning the impact to our area highlighted us for heavy snowfall rates from around 4:00PM onward.
One inch of snow per hour is quite heavy, but we were nowhere near done yet. The above image is of the 700MB level showing frontogenesis along with the centers of low pressure, fronts, and surface observation stations. Frontogenesis is basically the horizontal temperature gradient and its change over an area as a low is developing like the one off our coast that morning, and when it occurred over us in Connecticut it was mostly due to warm air advection as the warmer temperatures to our southeast pushed into the cold air present. Frontogenesis at the mid-levels from 700-850MB caused the deformation banding to form over us creating liquid, mostly in the form of snow, which fell with tremendous intensity overnight. Deformation banding is absurdly complex but involves moving air very quickly along with differences in moisture, temperature and pressure in small areas and creating all of this liquid.
The next Mesoscale Discussion image increased possible totals and really captured what was beginning to occur for us.
Two to three inches of snow per hour is an incredible amount, but we would still not be done there! The low was moving up the coast quickly pulling in moisture from the streams and the Atlantic, pushing warm air into cold air, creating convection and the beginnings of historic snowfall rates and totals. These 700MB and 850MB frontogenesis maps I saved from 11:08PM on Friday and 12:50AM on Saturday, respectively, help to display the forcing in the atmosphere in our area as we hit nearly unprecedented intensities of snowfall.
You do not have to be an expert to see the slice down the center of Connecticut going from the southwest to the northeast from near Fairfield to Bridgeport and New Haven up to Hartford on those maps, and this is not coincidentally the area that ended up with the greatest totals of snowfall. Getting there was the fun part as the radar absolutely exploded with some of the highest amounts of liquid you will ever see for winter precipitation.
There is that same section of Connecticut under the most intense areas of precipitation. At this point it was not all snow and bright banding was occurring in the Friday night period. Bright banding is a greater reflectively on radar (as seen by "heavier" intensities like above) of melting snow, ice, or rain as snow itself does not reflect as much of the radar beam and is not as large as those other forms of precipitation. In this case warm air had pushed far enough in to create an enormous layer of sleet that had pellets of huge sizes many people had never seen. It resembled hail from a thunderstorm more than what we think of as sleet. Graupel and even plain rain were even reported in some spots as this phenomenon moved across Connecticut and served to enhance the convection occurring. This is when those thunderstorms sprang up in the southeast and lightning was seen in many locations.
The area would turn back to all snow beginning around 9 to 10PM on Friday, cooling from east to west. At this point we started to see some reports of three or four inch per hour snows quickly surpassed by six or eight inches per hour in some areas! That is about the maximum rate at which snow can fall on the planet. I had about 10 inches of snow at 8PM on Friday and around 24 inches at midnight as I received 14 in four hours in Stratford. However, from 8PM to 10PM the snow mixed with and changed over to the heavy and large sleet described above. Considering the fact I had only around 12 or 13 by 10PM I think I came up with approximately 10-12 inches in two hours, the most coming from 11PM to midnight during whiteout conditions. Visibility was reduced to 100 feet or less and the winds whipped the snow in the definition of a blizzard.
These radar images at 12:31AM and 1:06AM Saturday show the banding and extremely heavy snow across Connecticut and more specifically near my area. You can see how localized it was at times and why some places ended up with much less than others.
This Mesoscale Discussion image showed where the band was around 1AM and where it would be going for the rest of Saturday as blizzard conditions took hold of the entire region.
Additionally, here are a few amazing infrared, satellite, and water vapor images that make the Blizzard of 2013 look a lot more like a hurricane than a winter storm.
The snowfall rates during these hours after must have been conservatively four inches per hour, and probably closer to six or more. I thought around 2AM I had a conservative 32 inches of snow down as the heaviest echoes moved away from me. Heavy to moderate and then light snow would continue for several more hours putting down at least several more inches. Even measuring the storm was obviously a problem because of the fact the wind was blowing it all over the place. I used a variety of techniques and averages to come to my totals as it went along, but during the morning after, from additional hours of wind and compaction, the totals did not reflect what we truly received.
Here is the final surface map for 7AM on Saturday morning as the historic Blizzard of 2013 moved away from New England with its banding lingering overhead.
As I considered total accumulations more in the days after the storm with a clearer and rested mind I have come to the conclusion that those of us in the central Connecticut strip seen in the radar images above likely all received at least 36 inches with many spots hitting over 40. This is not a belief shared by a lot of people outside those areas. But both professionals and amateurs like me who lived in these areas and stared at the radar and watched out their windows all night think it is. Measuring during the storm and comparing those totals to totals at dawn it seems utterly illogical that so little snow (an inch or two or less) could have fallen from around 1-2AM to the dawn when we saw heavy to moderate and then light snow lingering for hours. I said I had around 32 inches at 2AM and in open areas Saturday morning the best I could come up with was around 31 or 32 inches. I noted a lamp post here in the middle of an open lawn around 2:30AM that had a lower level of snow surrounding it several hours later. When the snow melts I will eagerly measure it from the ground to around the point I saw the snow reach and add in some more creative math to see where I think I really ended up. No one will ever be sure how much fell, but it was an astonishing amount.
One event cannot be classified as evidence of climate change or global warming, and this sort of storm can be expected every 100-200 years here. Nevertheless, I keep writing that in this blog every few months, don't I? Our world is changing and we are all witnesses. At least now the vernal pools have a better chance of being full of water this spring...
Scott Kruitbosch
Conservation Technician
Images via the National Weather Service, Wunderground, College of DuPage, the Pennslyvania State University, and the National Oceanic and Atmospheric Administration
