Thursday, February 2, 2017

State of the Southern New England Winter


The calendar reads 2/2 which means it is time for rodents all across America to tell us if we will see an early spring or a long winter.  New Englanders know to ignore the groundhog.  If spring breaks before the middle of April it is a minor miracle.  Merely reaching February is no cause for celebration as the shortest month often feels like the longest.  It also produces the most snow, on average, across the four major Southern New England climate sites (BDL Airport, Worcester Airport, Logan Airport, TF Green Airport).  Let's take a look at where we stand as we enter winter's busiest stretch.  As your unofficial, unelected, self-designated representative to Mother Nature, it is time for the 2016-17 State of the Southern New England Winter address.

I. 2016-17 So Far
In the meteorology world, winter runs from December 1 to February 28/29.  If that were true in SNE we would be 2/3's of the way through the winter.  But while March is spring like sometimes (2012),  most of the time it is just an extension of February.  Here is where we stand in regards to temperatures and snowfall so far.
Boston is down nearly 10" while the rest of the climate sites are actually close to, or in Providences case above, average so far.  That seems surprising given the warm temperatures so far.  December was close to normal while January was 5-7 F above normal.  Of course 5-7 above normal in January is still cold so that is why we still were able to accumulate snow.

The good news is there is plenty of snow in ski/snowboard country.  Winter break is upcoming for many and this is good news.

December 2016
Several snow events and one bitterly cold event in December made headlines.   The 12-15-16 Arctic Assualt was the coldest December temperature in Boston since 1983!  However, storms continued to take a track to our west so only some snow was able to fall despite the cold temps.  A storm the next day dropped 4-8 inches of snow across SNE.  Another storm a few days after Christmas added another 4-8 north and west of the MA Pike/495.  Temperatures finished a few tenths of a degree above normal for the month.


January 2017
The atmosphere changed as we entered 2017.  Now some may read this as a political statement but it is not.  After some snow January 6/7, there have only been a handful of light snow events.  The majority of the January snow was in SE MA/RI.  The stormy weather was found out west as one storm after another pounded the west coast with heavy snowfall and drought denting rain.  The upper atmosphere often produced a trough of low pressure near the West Coast or in the Western US.  This allowed for Pacific air to enter the weather pattern and a result New Englanders often saw seasonably mild temperatures.

Precipitation/Temperature Analysis
As already stated it has been warm in the Eastern US so far in 2017.  The cold can be found in the Pacific Northwest.  The rest of North America is red.
CFS v2 2 m temperature anomaly 12/4/2016 1 AM to 2/2/2017 1 AM
The winter temperature data can be found in the January 2017-preliminary climate table in the section I introduction.  The warmer air has helped bring needed precipitation to the region so far this winter.  Here are the last 60 days which begins 7 AM on 12/4/2016 and ends 7 AM 2/2/2017.  Around 0.30" of rain also fell on December 1 so add that to the totals you see.
NWS Accumulated Precipitation 12/4/2016 7 AM to 2/2/2017 7 AM (image Weatherbell)
The precipitation has been good enough to make a dent in the drought in parts of SNE.  Eastern MA, Southern Worcester County, and RI are in "Moderate Drought" instead of "Severe" or "Extreme Drought" where we were a few months ago.  That designation now resides in SW MA and NW CT.  Severe drought still exists in Northern Worcester County and Southern NH.
US Drought monitor 11.1.16 vs 1.31.17
The storm track in December was to our west which ended a large portion of the Western NY.  We could use some drought denting rains like that in Southern New England.  2017 is off to a good start in Boston and Providence.  Northbridge has an official National Weather Service precipitation collection station so let's add the hometown to the list.

II. The Rest of Winter
In December I wrote a post titled "Make December Snow Great Again" and proceeded to make the case that December snow in recent years has been "Sad!"  The recent post-February 1 snow has been "tremendous" and in some cases (2015) truly the best.   I analyzed each winter since 2000-01 to get a sense of how the 21st-century snow patterns.
click to enlarge
Recently only 2013-14 has seen more snow pre-Feb 1 than post-Feb 1 and that was only in Boston and Providence.  However, from 2007-08 to 2011-12 (2010-11 in Worcester) there was more snow before Feb 1 than after!  In my selfish desire (and all you folks who want a White Christmas) to make December snow great again, I forgot about the greatness of Post Feb 1 snow, especially recently.
History tells us that in general, more snow falls before 2/1 than after (except Worcester).  Lately, the opposite has been true.  So to get an idea of what to expect for the rest of winter we must look forward and stop looking back.  The 45-day temperature outlook for the US government Climate Forecast System likes a warmer than average look for the next 45 days (through 3/19).
CFS v2 45 day temperature outlook (image Weatherbell)
There looks to be a 2-week cold shot followed by above average temperatures through the end of Feb.
CPC 10-14 day temperature outlook 
I'll focus more on the upcoming snow pattern in a blog this weekend.  There is a chance Tuesday-Wednesday.  It looks like a storm will take a track similar to the storms in December, which means it will track inland.  There is potential for plowable snow before a change to ice and rain.

So some good news as I close this address to the Southern New England weather faithful.  By February 28 the sun will set at 5:36 PM in Worcester.  On March 12 the sun will set at 6:51 PM.  The average high temperature for February 28 in Boston is 41.  We are getting there. We must stay vigilant as February Nor'easters are famous for making a mess in a hurry.   Thanks for reading.

-Zack Green

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