WINTER STORM WATCHES HAVE BEEN HOISTED FOR THE ENTIRE WMASS REGION… MAJOR LONG-DURATION SNOWSTORM APPEARS TO BE ON THE WAY… SOME FOLKS WILL SEE UP TO A FOOT, MAYBE A BIT MORE… SNOW BEGINS SUNDAY LATE MORNING WITH SEVERAL INCHES BY EVENING… SOME MIXING NUDGES NORTH TO LEVEL OF MASSPIKE OVERNIGHT… COLD AIR CRASHES SOUTH AND EAST MONDAY MORNING, PRECIP INTENSIFIES WITH SECONDARY LOW AND WE SNOW ALL OVER AGAIN THROUGH MONDAY AND INTO MONDAY NIGHT… 1ST DAY OF METEOROLOGICAL WINTER KICKS OFF WITH A BANG… GEAR UP, PEEPS… (6:30pm Friday)
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Good evening folks, #AndSnowItBegins, indeed!
I’ll start of with a quick run-through of our weather through Sunday mid-morning, then drop into a discussion of the actual storm itself. Post-storm weather info will not be included in this post, as it just looks fairly dry and seasonable from Tuesday into next week.
A COLD SURFACE SETS UP SUNDAY AM
Expect light northwest flow tonight as temps drop down into the mid to upper teens for lows under mostly clear skies.
High pressure builds through northern New England and southeast Canada providing a mostly sunny day with highs only in the low to mid 30s.
An exceedingly dry air mass will be formed over the WMass region Saturday night as radiational cooling is maximized with lows crashing into the low to mid teens by early Sunday morning.
By mid-morning, very dry air will be in place across our region. Dew point temps will only be in the 5-12 degree range, whereas actual air temps will be in the low to mid 20s.
The difference between dew point temp and air temp is called the dewpoint depression. Those are wide depressions, and when snow arrives by late morning to near noon and starts precipitating into this dry air, our day time highs won’t be climbing much as dews rise, and the airs fall to meet each other (a/k/a “wet bulb effect”).
STORM SET UP AND SYNOPSIS:
PLOWABLE SNOW INCOMING
An upper level low pressure system will tracking east through the southern Great Lakes on Sunday morning.
Initial precipitation bands from this system will slam into our very cold and dry air at the surface.
In turn, this will produce a perfect cold, dense overrunning surface for precipitation to rise up and over, and to then precipitate snow down into, at first drying before reaching the ground (a/k/a “virga”) but then quickly saturating the air, which will allow snow to reach the ground by about noon, give or take.
The ground will be very cold from the night before, and so snow will stick QUICKLY, so driving conditions will become slippery quickly as well.
It’s our first widespread snowfall, so give yourself extra time if you must travel, plenty of space between you and other cars, and have your resources in the car in case you get stuck.
This front-end thump of steady moderate snow is expected to fall all afternoon and drop several inches by Sunday evening, think 3-6″, generally speaking.
PHASE TWO
Then we enter a middle period as the secondary low will just be forming off the New Jersey coastline, but will still be to our southwest.
The first overrunning bands with the original/parent low will be exhausted to a degree, and the secondary low won’t be cranked up yet either.
This when we should see some milder air nudge northward aloft Sunday night into early Monday morning, producing either periods of light snow north of the MassPike with additional very light accumulations overnight, or sleet and freezing rain with some ice glazing south of the Pike, which is where snow totals are expected to be lowest into northern CT (mainly norther central and northeast CT… northwest CT looks like 8-12″, maybe a touch more, more on snow totals for the rest of us later).
FINAL PHASE
By Monday morning, we will enter the third phase of this winter storm where any icing will change back to snow.
Our secondary low should be tracking east of the longitude of the CT River by that time, AND developing and deepening into a stronger winter coastal low.
This will not only start to develop heavier precip bands and sending them northward into the WMass region, but it will also be wrapping colder air around the north side of the low and pulling it into WMass.
At the same time, the upper low will reach the developing secondary low, and “vertically stack”, which will tend to slow the eastward progression of the storm on Monday.
This is why the storm is expected to be a longer-duration, potentially 36-hour event.
This all means more and heavier snowfall on Monday and into Monday night before tapering to periods of light snow showers or flurries late.
Our coastal storm will be positioned near Martha’s Vineyard or Nantucket by Monday evening, and will then pull away to the east on Tuesday.
SNOW TOTALS BY TUESDAY MORNING
I think south of the MassPike (except for Berkshire County and Litchfield County CT) we can expect 4-8″ with some icing Sunday night into Monday morning.
I think north of the MassPike (but including all of Berkshire County and Litchfield County CT) across CMass, WMass, the Taconics of eastern NY, southern VT and southwest NH, we will see 8-12″, with some isolated up-to 15″ amounts, with the best chance of any 12″+ amounts occuring in the western hilltowns, eastern Berkshires, and southernmost Green Mountains along/south of the Rt. 9 corridor in southern VT.
WIND
We can also expect northerly wind gusts of 20-30mph during the storm, mainly on Monday.
GET YOUR REPORTING HATS ON, FOLKS!
Clean those photo lenses, dust off those yard sticks, crack those knuckles, and stretch those fingers because I will be looking to you to help me with condition reports throughout the storm.
EVERY STEP OF THE WAY
I will be posting main reports, updates, and all manner of info during the entire winter storm, from start to finish, with a wrap up Tuesday morning.
So stay tuned for updates, and get ready, because unless something extreme happens to derail this thing (which has happened before, but I don’t think it will this time) we’ve got a legit first-of-the-new-season snowstorm on the way!
Stay tuned!
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