Archive for January, 2014

Nearing the midpoint of winter
January 12, 2014

By Meteorologist Mike Skurko

This week marks the midpoint of meteorological winter, defined as the full months of December, January, and February.  Before winter began, we presented the expected snowfall for western Massachusetts this season in the CBS3 Pinpoint Weather Winter Outlook.

The forecast called for 60 to 70 inches of snow.  Using a midpoint of 65 inches, that would be about 60% more than our average winter.  Let’s check out how we’re doing so far:

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The numbers in white represent an average winter, while the numbers in blue represent the actual snowfall so far this season.  The average winter at Bradley Int’l is 40.5 inches of snow, which would calculate to 14.2 inches through today, January 12th.  So far, however, we have already received 21.3 inches of snow … exactly 50% above average at this point of winter.

So, we’re not quite at 60% above average, but we are certainly well ahead of the normal pace with snow so far this winter.

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The polar vortex
January 11, 2014

By Meteorologist Mike Skurko

The record cold that gripped the nation this past week spawned the headline “polar vortex” among mainstream media.  What exactly is this catchy-sounding polar vortex?  While it got a lot of buzz this week, it’s not a new concept at all, at least not to meteorologists.

First of all, the polar vortex is not an individual storm like a hurricane or tornado.  Social media pictures and videos “capturing” the polar vortex moving through are completely incorrect.

The polar vortex is a permanent area of low pressure spinning in the upper-levels of the atmosphere in the Arctic, thus the term “polar.”  This area of low pressure has two centers, one near Baffin Island, Canada and another in Northeast Siberia.  The “vortex” refers to the strong winds swirling around this low, which contains the pocket of the brutally-coldest temperatures within the Arctic.

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Occasionally these winds weaken, which disrupts the shape of the vortex.  If other atmospheric conditions are favorable, such as the position of the jet stream, it can allow a part of those coldest temperatures to drain south into the U.S. instead of staying confined to the polar regions.

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Therefore, only a piece of the cold air associated with the polar vortex makes it into the U.S.  The polar vortex can be deemed responsible for a cold outbreak.  However, the polar vortex will not suddenly find itself entirely centered over the U.S.  It’s also a very broad area, and will not enter the U.S. at a specific time and specific place like the eye of a hurricane making landfall.

In November, our CBS3 Pinpoint Weather Winter Outlook briefly talked about the Arctic Oscillation.  The distortion of the polar vortex … how the winds weaken or strengthen around this Arctic low … essentially is the Arctic Oscillation.  When the winds around the polar vortex weaken and allow the coldest air to drain a little southward, that is known as a negative phase of the Arctic Oscillation.

To further demonstrate the polar vortex, check out the low temperatures on Monday across North America (top image) and Friday (bottom image):

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Notice how the Arctic air spilled south into the U.S. on Monday, and then retreated back to the north by Friday.  Meanwhile, check out the temperatures across the far northern Canadian territories.  Their temperatures didn’t change much at all (staying with the purple numbers of about 20 to 30 below zero).  This is the permanent area of Arctic air that typically stays up to the north.  When those upper-level winds weakened, we got a taste of those same numbers in the U.S. on Monday as part of the “polar vortex” draining to the south.

2013 in review
January 5, 2014

By Meteorologist Mike Skurko

Now that Thursday night’s snowstorm is behind us, we now have some time to look at the numbers for 2013.  Despite all of our ups and downs weather-wise over the last year, things found away to even out back to normal.  Every arctic blast in the winter was cancelled out by a heat wave in the summer; every mild spell in the spring was evened out by a cold snap in the fall.

When all was said and done, our high temperatures just averaged 1/15 of a degree above normal … an incredibly small number even when its averaged out over the year (2012 finished a full 2.9 degrees above normal).  Low temperatures were about 0.3 degrees above normal, and total precipitation was at 51.51 inches … 5.86 inches above normal.

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2013’s biggest weather headline was the February blizzard.  On Friday, February 8th, a true blizzard slammed southern New England, and dumped more than two feet of snow on the Pioneer Valley.  Final snowfall reports from that event are archived on the weather blog here.

After 57 inches of snowfall for the winter of 2012-2013, the above-normal precipitation trend continued in the summer, as seen above.  More than 10 inches of rain fell in June, sending the Pioneer Valley to it’s second-wettest summer on record.

Fortunately, in terms of severe weather, the summer of 2013 was rather quiet compared to the last couple of years.  The biggest headline for western Mass was a microburst in Agawam.  And good news up-and-down the east coast, it was unusually quiet in the tropics.  Only two category one hurricanes formed in the Atlantic, neither making landfall in the U.S.

The abundance of moisture over the summer kept things green, and sunnier skies through early fall meant great news for seasonal businesses, such as golf courses, local vineyards, and the fall foliage.

The next seasonal businesses to take care of are the ski resorts.  December fell just shy of a new monthly snowfall record, a good jump start to the season, and the snow from Thursday night’s storm should provide an excellent base for the new year.

Record cold this morning
January 4, 2014

By Meteorologist Mike Skurko

Record cold temperatures greeted the Pioneer Valley this morning.  Here is the list of low temperatures across western Mass this morning, courtesy of National Weather Service SKYWARN spotters:

Heath: -16
Easthampton: -14
Greenfield: -13
Colrain: -12
Monson: -11
Palmer: -11
Amherst: -10
Deerfield: -10
East Longmeadow: -9
Shelburne: -9
Charlemont: -8
West Springfield: -8
Granville: -7
Northampton: -7
Chester: -6
Shutesbury: -6
Williamsburg: -6
Springfield: -5
Chicopee: -5
Ware: -4

Meanwhile, the official records dating back to 1905 are kept at Bradley International, which recorded an overnight low of -9.

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I guess we shouldn’t complain too much though.  This is a raw computer model of the temperature at 7 a.m. Sunday morning.  That shade of red across Minnesota indicates temperatures (not wind chills) of 20 degrees below zero and colder.  Gray, white, and pink are also temperatures below zero.

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(Click to enlarge and see the actual numbers)