Archive for September, 2013

The science of leaf colors
September 28, 2013

By Meteorologist Mike Skurko

Why do the leaves change color in the fall?  To put it in one simple sentence … the production of green chlorophyll breaks down as the weather cools, which revels the yellows, oranges, and reds lying underneath.

During the growing season, chlorophyll is produced as part of photosynthesis.  Photosynthesis, which you probably learned all about in elementary school, is the chemical process that turns sunlight into sugar, which is vital for the tree to nourish itself.

Meanwhile, carotentoids are also found in the leaf cells during the year, which are responsible for the yellow and orange colors.  However, they are hidden underneath the green chlorophyll during the growing season.  As fall settles in and the days become shorter, the available sunlight becomes less and the photosynthesis process slows down.  This also slows down, and eventually stops, the production of chlorophyll.

This causes the green color to be lost and the yellow and orange carotenoids to be revealed.  Therefore, the leaves do not necessarily “change” color, they more accurately “lose” their green color and “reveal” the yellows and oranges already underneath.

Red colors come from anthocyanins, which are produced at the end of the growing season.  These come from the excess sugars that are produced to be stored for winter.  The better conditions trees have to produce more sugar heading into fall, the better the red colors will be revealed with the yellow and orange carotentoids.  Ideal conditions for anthocyanins fill out the color palette and create the most spectacular fall foliage.

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Harvest moon, fall preview
September 19, 2013

By Meteorologist Mike Skurko

Crowds at the Big E, chilly mornings, and Wednesday night’s harvest moon all point to the same thing…fall is here, almost.  The autumn equinox occurs precisely on Sunday at 4:44 pm.

The last full moon of summer is known as the harvest moon.  Before electricity, farmer’s heavily relied on the additional moonlight from a full moon, allowing work to continue late into the night harvesting their crops before colder weather sets in.

The hilltowns have been touched by frost advisories already this month, and the first killing frost for Springfield typically checks in around mid-October.

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Fall foliage is already beginning to appear in northern New England, with western Massachusetts typically scheduled to reach peak color in mid-October as well.  While a very rainy summer promoted green leaves, it must remain cool and much drier in the weeks ahead to promote the best fall colors.

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Between the first frost, the leaf colors, and a sunset 50 minutes earlier by this time next month, grab the last you can of summer, as fall is quickly approaching.  Here are some other dates to keep in mind:

Oct. 1 – earliest snow on record at Bradley Int’l (trace in 1981)

Oct. 10 – earliest measurable snow on record at Bradley Int’l (1.7 inches in 1979)

Oct. 29 – anniversary of the October Nor’easter

Nov. 5 – halfway point of autumn, average high: 55, average low: 36

Nov. 17 – average low temperature drops to 32 degrees

Nov. 28 – Thanksgiving Day

75th anniversary of 1938 New England hurricane
September 15, 2013

By Meteorologist Mike Skurko

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While the 2011 tornado, October nor’easter, and last year’s Superstorm Sandy are fresh in our mind, next weekend marks the 75th anniversary of perhaps the most destructive storm to ever hit southern New England … the Great New England Hurricane of 1938.

The storm caught virtually everyone in this area unprepared.  Moving north up the Atlantic coast at 50 mph, the category 3 hurricane made landfall over Milford, Connecticut.  The storm produced tides up to 25 feet along the southern New England coast, and recorded a peak wind gust of 186 mph at the Blue Hill Observatory near Boston.

Another frontal system just a few days prior already produced several inches of rain in the region, with the hurricane providing several more.  The National Weather Service puts the Connecticut River Valley’s rainfall estimates at 10 to 17 inches from these two storms.  More than 500 were killed and 1700 injured.

The National Weather Service has put together a nice website full of photos, maps, and newspapers of the Great New England Hurricane of 1938:

Our media partners, Masslive and The Republican, also looked at how the science of hurricane tracking has significantly improved since: 75 years after the Hurricane of 1938, the science of storm tracking improved significantly

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2013 Big E weather possibilities
September 14, 2013

By Meteorologist Mike Skurko

It’s common knowledge that weather plays a big role in the attendance numbers at the Big E.  A weekday bothered by rain can keep the attendance below 20,000.  A sunny and comfortable Saturday or Sunday has put the attendance well over 100,000.

Attendance appears to slowly rise each and every year, but a notable exception came in 2010 and 2011.  Both of those years had more than 4.5 inches of rain during the 17 days of the Big E.  The normal amount of rain for that 17-day stretch is a closer to two and a half inches.  Rainfall was closer to normal for last year’s Big E, helping another record for total attendance to be set.

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We had a wetter-than-normal summer so far, and if that carries through this month, history shows it may be hard to set a new attendance record for the 2013 Big E.  On the other hand, Friday kicked off the 2013 Big E with an opening day record of 69, 851.

Temperatures typically do not deter the crowds too much.  In fact, high temperatures were below normal for last year’s record-setting Big E.  The second-largest year was in 2009, and temperatures were still about 4 degrees below normal.  Our average highs are in the mid-70s now, but that will drop to the upper-60s by the end of the Big E.

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Despite the unusually hot day this past Wednesday, 90-degree heat is very rare at the Big E.  Record high temperatures through the end of the month stay in the upper-80s and lower-90s.  In fact, the record high for September 28, the final Saturday of the Big E, is only 83 degrees!

Waterspout captured at Quabbin Reservoir
September 7, 2013

By Meteorologist Mike Skurko

Last weekend featured heavy rain for parts of western Massachusetts, and now some incredible photos have surfaced of a brief waterspout over the Quabbin Reservoir on Sunday, September 1.  The photos come from Joe Stafford, who was working for the Massachusetts Department of Conservation and Recreation near gate 8 at approximately 6:25 p.m.

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According to the National Weather Service, it was only about 10 yards wide and traveled only one-tenth of a mile (about 176 yards).  While radar clearly indicated a strong storm and heavy rain in the area at that time, it was impossible to detect such shallow low-level rotation over the Quabbin.  Below are two archived images courtesy of the National Weather Service and Iowa State University.

The first one is the normal radar that we all know and love, and it clearly shows the presence of a strong storm.  The second image, however, is a radial velocity image.  Simply put, green represents winds blowing toward the Boston radar, purple represents winds blowing away from the Boston radar.  A bright green and bright purple pixel paired immediately next to each other indicate rotation typically capable of producing a tornado [a more detailed explanation can be found in this previous entry on the CBS3 Pinpoint Weather Blog: Doppler Radar and Tornadoes Part II]. The radial velocity image from this storm was not even close to showing this behavior.

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Summer 2013 recap
September 1, 2013

By Meteorologist Mike Skurko

Meteorological summer, defined as the full months of June, July, and August, is now in the books.  For Bradley International Airport, the official NOAA climate station for the Pioneer Valley, this summer will go down as the 2nd wettest and 8th warmest on record (dating back to 1905).

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