Early-mid February does it **again**!!
I was born and raised in Somerville, New Jersey. It’s in the north-central part of the state, southeast of the higher elevations and close enough to the coast that my childhood hopes for a big snowstorm were crushed many times. I’d be awakened to the ping-ping of sleet, then it’d change to rain and wash away what little snow had fallen.
There were two exceptions: February 7, 1967 and the "Lindsay Storm" of February 9, 1969.
Those dates have been forever etched in my mind.
Then as I learned about meteorology and forecasting during college and the first part of my professional career, the most memorable snowstorms in the northeast U.S. during those years included the Blizzard of ’78, the first Presidents’ Day Storm (1979) and the Blizzard of 1983. All occurred during early-mid February.
This has continued to fascinate me, and the early-mid Feb storms have kept on comin’.
I posted a blog entry on weather.com about it in 2007, and then in 2010 I was amazed yet again! (That was just prior to the storm that came to be known as “Snowmageddon.”)
In the latter, about this phenomenon I wrote, "... I'm not sure exactly why that is; perhaps it's a reflection of an underlying meteorological tension between winter being firmly entrenched in North America but the atmosphere sensing the first signs of the coming change in seasons.”
I.e., is it at just the right point between midwinter and pre-spring, as the atmosphere is still close to the climatologically coldest point of the year in North America with ample arctic air often still available yet incoming solar radiation and warmth are increasing, the sun having recently risen in places such as Barrow, Alaska and in the southern U.S. its rise ~13° higher above the horizon by two months after the December solstice being noticeable? Does that create just the right volatile conditions, in combination with something going on with atmospheric waves that favors explosive cyclogenesis near the Northeast coast?
I don’t know, but the way the atmosphere so frequently finds a way to crank up a whopper snowstorm there during a short period amidst the winter is uncanny.
As anticipation rose this week about a storm that has the potential to be exceptional even by the standards of blockbuster blizzards, I wanted to check actual data – always a good thing to do! – to see whether my anectodal impression is supported.
It turns out that the storms which have been Category 3, 4 or 5 on the Northeast Snowstorm Impact Scale (NESIS) developed by the preeminent authorities on northeast U.S. snowstorms, Paul Kocin and Louis Uccellini (named today as the next director of the National Weather Service), have commenced during a ~3 month period from December 11 to March 12 but more than half of those have been within a ~3 week period from February 1 to February 23!
Source: NOAA NESIS page
Now will another one be added to the list? Meteorologists including me are haunted by past cases in which all models showed the same outcome yet busted, but at this point the event is close enough and there’s enough consistency from run to run and amongst different models that now the only uncertainties are the small-scale details of the storm. And, thus, BTW, barring something stunningly unexpected, this will be another, win for the ECMWF (European) weather forecast model, which locked onto the storm many days in advance. (At least it’s a W for its “operational” as opposed to “ensemble” runs, but that’s a whole other topic!)
There are two pieces of the storm TWC named Nemo (the "N" storm on this season's list) that are going to come together combustibly to ignite a meteorological bomb (latest model runs are showing the central pressure drop meeting or coming very close to the criteria of 24+ millibars in 24 hours). One has brought snow to locations such as Milwaukee and Chicago, while the other, to the southeast, is collecting copious amounts of Gulf and Atlantic moisture. The trough associated with the former will “dig” and pull in the latter, the primary surface cyclone, rather than it sliding out to sea. Speaking of the sea, its surface temperatures in the Gulf Stream offshore of the Mid-Atlantic and New England are running well above average, which is interesting (and might add a little extra oomph to the system?).
Radar mosaic, 10:51 pm EST Thursday 7 January 2013. Image credit: WeatherTAP.com
GFS model, 12UTC Thursday 7 February run, 850 millibar vorticity forecast through 12UTC Saturday February 9. Image credit: The Weather Channel
There are some differences between this storm and the New England Blizzard of ’78 (which occurred 35 years ago this week and shortly after the “Cleveland Superbomb” – what a winter that was!), but also some similarities, including a strong high pressure system oriented like a banana to the north and west which is supplying cold air and against which the low pressure system will be butting, creating a tight pressure gradient.
Thus, along with ingredients for very high snowfall rates & total accumulations, wind is going to be an important factor in this storm, with blowing & drifting and low wind chill temperatures – dangerous, life-threatening conditions in which to be stranded outside – as well as power outages and coastal flooding.
Stay safe, everyone!