Archive for February, 2013

Dreary week ahead
February 24, 2013

By Meteorologist Mike Skurko

If you’ve looked at the 7-day forecast, you’re probably not thrilled at all of the precipitation from Tuesday evening and beyond.  The reason for this is a slow-moving, large low pressure system developing in the Great Plains and crawling it’s way into the northeast.

The following 4 images are a computer model for Tuesday morning, Wednesday morning, Thursday morning, and Friday morning, respectively.  The images are depicted for the 700-mb level, or about 10,000 feet up.  Orange represents dry relative humidity (suggesting calmer weather), while green represents high relative humidity (suggesting cloudier weather).  Images courtesy Penn State Meteorology.

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Notice how the upper-level low pressure system, marked with a big red “L”, is slow to move through the eastern United States.  In this computer simulation, the center of this upper-level low only moves from Southern Missouri on Tuesday to New York City by Friday … this translates to 1,100 miles over 4 days, or a speed of about 11 mph … hardly a quick-moving system.

While it appears the snow and rain expected Tuesday night and Wednesday will be rather persistent, fortunately it should be much more scattered beyond that (evident by the darker shade of green Wednesday morning versus the lighter shades of green on the last two images).  So enjoying tomorrow afternoon’s sunshine because there will not be too much sunshine beyond that for the rest of the week.

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Saturday night technical discussion
February 23, 2013

By Meteorologist Mike Skurko

Earlier this week, rumors of another major snowfall for tonight were starting to swirl around western Massachusetts.  Clearly that is not going to be the case now.  Even in the last 24 to 48 hours the predicted snowfall continues to be less and less with each passing model run.

One explanation for this is that the low pressure center has bumped itself further north over the last several model runs.  The 540-line (the “rain/snow” line) has moved northward into our region as a result.

The following 4 images depict the low pressure center and the 540-line (the red dotted line through southern New England) for the last 4 model runs.  These are “ensemble mean” models, meaning each image is more or less an average of all the model runs for that time.  Each image is for 10 p.m. tonight.  The first image was from the 4 p.m. model initialization last night.  The second model was run at 10 p.m. last night, the third was from 4 a.m. today, and the final image was from the model run at 10 a.m. this morning.

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At first glance, all four images may not appear all that different.  But take a closer look, and pay particular attention to that 540-line.  For the first image (the model run at 4 p.m. yesterday) the 540-line is stretched out across the Interstate 84 corridor through Connecticut.  Each successive image inches that line just a little further north, and by the last frame (from the model run this morning) we see the 540-line has pushed itself into the downtown Springfield area.

Also notice how the low pressure system is enlongated just a little bit more to the northwest by the last frame, which is helping budge this 540-line north.  It’s subtle, but it’s a huge contributor why we’re expecting a little more rain and a little less snow tonight.  If you’ve been watching the radar over the last few hours, you would have also noticed a mix of rain and snow across Hampden county early this evening, rather than an all-out snow.

Overnight we will see this 540-line sag as some colder air wraps in behind this system, which will eventually allow for more places to changeover to snow.  However, accumulations are still expected to be minor across the Springfield area.

Defining the Blizzard of 2013
February 16, 2013

By Meteorologist Mike Skurko

Last weekend’s blizzard across New England that brought about 2 feet of snow to the Springfield area was only an “official blizzard” for select parts of New England … mostly towards the coast.  The definition of a true blizzard has 3 criteria points that must all be met for 3 consecutive hours:

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Western Massachusetts was right near the cut-off line for true blizzard criteria.  Westover Air Reserve Base in Chicopee and Barnes Municipal Airport in Westfield both were close to blizzard conditions.  After the National Weather Service spent a few days after the storm sorting through all the data, here is their official Public Information Statement regarding which towns in Southern New England experienced a true blizzard:

Blizzard conditions were reached at many locations across southern New England during the storm on February 8 and 9.  Thus it is safe to call this the Blizzard of 2013 for southern New England.  Certainly public perception of this event was that it was most definitely a blizzard.

When reviewing whether a particular observation location had blizzard conditions, we counted visibilities equal to 1/4 mile since that is quite low for an automated visibility sensor to be able to detect.  We also made some subjective decisions.  For example, in Manchester, NH, blizzard conditions were met for a consecutive 2 hours 40 minutes, and we considered this close enough to the 3 hour requirement.   At Boston Logan International Airport, within a 6-hour period blizzard conditions were observed for 4 of those hours.  Thus we decided to count this even though there were only 2 consecutive hours.

The following observation sites clearly had blizzard conditions.  Durations listed are approximate:

Worcester MA…. 8 hours
Norwood MA…… 7.5 hours
North Smithfield RI…5.5 hours
Bedford MA…… 4.5 hours
New Bedford MA…4.5 hours
Newport RI…….3.5 hours
Hartford CT……3.0 hours…at Brainard Field

The following observation locations were determined to have also had a blizzard:

Westfield MA…..2.75 hours…rounded up to 3
Manchester NH….2.75 hours…rounded up to 3
Marshfield MA….2.5 hours before power went out but likely contd
Boston MA……..2.0 hours continuous…but 4 of 6 hours blizzard
Taunton MA…….2.0 hours continuous…at least 3.5 hours total before data outage

It should be noted that the following sites had near-blizzard conditions:

Providence RI
Westerly RI
Chicopee MA

The following sites may have had blizzard conditions but data were lost at the height of the storm:

Beverly MA
Plymouth MA

Western Mass. final snowfall totals
February 9, 2013

By Meteorologist Mike Skurko

Here are the final snowfall totals reported to the National Weather Service for the February 8th – 9th storm.

Hampden County
Southwick   28.3
Agawam   24.0
Monson   24.0
Blandford   24.0
Westfield   23.0
Chester   22.0
West Springfield   21.0
Ludlow   20.5
East Longmeadow   20.0
Springfield   18.5
Chicopee   18.0
Palmer   18.0

Hampshire County
Westhampton   25.0
Northampton   24.0
Wales   22.0
Amherst   21.5
Granby   21.0
South Hadley   20.0
Huntington   20.0
Belchertown   18.5
Amherst College   17.8
Worthington   16.0
Ware   16.0
Plainfield   15.9

Franklin County
Leverett   23.0
Greenfield   20.0
Turners Falls   19.0
Shelburne   19.0
Warwick   16.6
Colrain   16.0
East Charlemont   15.5
Heath   14.0

Berkshire County
North Otis   22.0
Alford   20.0
Peru   18.7
Lenox   12.1
Lanesborough   11.0
Great Barrington   11.0
Housatonic   10.0
Williamstown   10.0

Below is an image for the radar estimated snowfall across southern New England.  It easily depicts the hardest hit areas … central and eastern Connecticut, as well as eastern Massachusetts from Worcester to Boston.  The highest snowfall totals per state include

Hamden, CT   40.0
Spencer, MA   31.0
West Glocester, RI   27.6

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