Well, as I note below, my first forecast back on the 17th was for not much of a storm for our area, and that turned out to be true. In the intervening days, the short-range models suggested the storm would be able to press farther into the arctic air mass. And, as we can see from the graphic above, that didn’t happen.
— Winter Storm Warning is Cancelled —
— Wind Chill Advisory in Effect until 10 AM Today —
1700 1/21 fcst
Storm Total: 2.3″ snow.
I woke this morning to my lovely bride saying “Lucy, you’ve got some ‘splaining to do!” I should have stuck with my synoptic forecast of the 17th when I said the arctic front would protect us from this storm! The arctic air mass, along with persistent winds from the north, kept the storm shield from pushing into our area. The cutoff of the northern shield of the storm was very sharp – Leominster received 0.8″, Worcester 1.8″, Shrewsbury and Westborough 2.3″, Milford got over 6″. According to the DWC Mobile Unit, driving this morning in ~2″ of snow was very difficult in Worcester (as it typical), and Worcester schools have a 2-hour delay. Shrewsbury and other local schools are open per usual.
Just keep in mind that the Cape and south coastal areas are still under a blizzard warning. Snow totals being reported to NWS Taunton for this area are in excess of 16″ and it is still accumulating. Driving in this area should be avoided if at all possible.
Also, be cautious outside today. Temps are frigid and winds will contribute to wind chills well below zero.
Steve
On Tue, Jan 21, 2014 at 5:32 PM, Stephen Daukas wrote:
— Winter Storm Warning in Effect from 1 PM Today to 1 PM Tomorrow —
— Wind Chill Advisory in Effect from 10 PM Tonight to 10 AM Tomorrow —
Shrewsbury Area Weather for Today/Tomorrow, 1/21-22/2014 (see disclaimer at bottom)…
1700 1/21 fcst
Total precip: ~6.4″ to ~8.1″ of snow by Wednesday PM.
Details:
Forecast snow totals are unchanged. In my last update, I said I was leaning towards the higher end of the forecast range and this time I’m leaning towards the lower end… That is usually a sign that the forecast has settled down… Also, timing of the end of precip has shifted a bit earlier to ~11:30 AM, although the warnings are set to expire at 1 PM.
My last update called for Virga to changeover to snow at ~3:15 PM and it started snowing at 3:19 PM in Shrewsbury (I just happened to be outside when the snow began). Not bad, but that made me think of the Heisenberg Uncertainty Principle! 😉
Cancellations are starting to pile up as anticipated. (You know its going to be a bad snow storm when Our Lady of Hope closes!)
Again, if you have to travel, check local weather outlets and monitor news forecasts before heading out on the roads.
Next update either later tonight or tomorrow AM.
Steve
On Tue, Jan 21, 2014 at 1:02 PM, Stephen Daukas wrote:
Shrewsbury Area Weather for Today/Tomorrow, 1/21-22/2014 (see disclaimer at bottom)…
1230 1/21 fcst
Timing is a bit slower for our area with snow reaching the ground ~3:15 PM (although it is already snowing over south coastal zones, which is earlier than expected). The start of the evening commute will not be as difficult as anticipated, but the heavier snow should arrive ~6 PM. Still on track for the remainder of the forecast below.
Next update will be early this evening.
Steve
On Tue, Jan 21, 2014 at 8:01 AM, Stephen Daukas wrote:
Shrewsbury Area Weather for Today/Tomorrow, 1/21-22/2014 (see disclaimer at bottom)…
0600 1/21 fcst
Total precip: ~6.4″ to ~8.1″ of snow by Wednesday PM.
Details:
We now have a nice setup for snow: cold temps and a strengthening Low near to the 40/70 benchmark south of Nantucket. The track of the storm has shifted a bit such that we will be getting more snow than what was forecast yesterday… The Cape will likely see blizzard conditions (and is under a blizzard warning). QPF actually hasn’t increased all that much, but I have increased my forecast snow totals by ~1.5″ (and am leaning towards the higher end of the forecast range) due to the very cold temps (higher snow ratio) and the storm track shift towards the benchmark.
More technically, the Low will move along the stalled arctic front along the mid-Atlantic as a consequence of a very strong short wave moving out of the Ohio valley. The timing of the snow is still as described in my earlier forecast, with snowfall beginning early afternoon and increasing snowfall rates by ~6 PM as the Low approaches the benchmark. Strong pressure falls associated with the Low will allow for banding (periods of very heavy snowfall and limited visibility) and high winds gusting to 30 MPH for our area, higher snowfall and winds to our south.
Today’s evening commute and tomorrow morning’s commute will be difficult. Expect some cancellations this afternoon and numerous closings and cancellations tomorrow. Again, keep in mind that frigid temps allow for snow to instantaneously adhere to surfaces, and treated surfaces will still be slick. If you must drive during this storm, be extra cautious. This storm will develop fairly quickly as it picks up moisture from the Atlantic, and it could deepen more than currently expected.
You should continue to monitor local media outlets for updates and additional warnings during the day today, and be prepared for a difficult evening commute. Tune your NOAA All Hazards Wx Radio (that you all have, of course) to Channel 7 for the Worcester area for any late-breaking changes…
I will send updates as the storm develops.
On Mon, Jan 20, 2014 at 5:36 PM, Stephen Daukas wrote:
— Winter Storm Warning in Effect from 1 PM tomorrow to 1 PM Wednesday —
Shrewsbury Area Weather for Tuesday/Wednesday, 1/21-22/2014 (see disclaimer at bottom)…
1700 1/20 fcst
Tomorrow
Dew Point ~1°F, High T ~17°F, Low T ~9°F, Winds NNW – NNE @ 6 – 14 MPH
Precip: PM Snow
Wednesday
Dew Point ~-4°F, High T ~13°F, Low T ~2°F, Winds N – WNW @ 9 – 15 MPH
Precip: AM Snow
Total precip: ~5.8″ to ~6.4″ of snow by Wednesday PM.
Details:
The arctic air mass that looked like it would hold this storm far enough out to sea such that we would be spared, isn’t quite doing what I hoped… The ocean-forming storm will, in fact, be SE of the 40/70 benchmark, but still close enough for us to get a good portion of the snow that will be concentrated over Cape Cod.
The QPF (quantitative precipitation forecast) for this storm is as much as 0.8″ (liquid equivalent) over the Cape. Because of the arctic air mass emplaced over the region, the usual snowfall to liquid ratio of 10:1 is out the window. Ratios would be closer to 15:1 or even as high as 20:1. This cold cold air actually makes it a bit harder to discern the depth of snow that will accumulate on the ground. My math comes out to between ~5.8″ and ~6.4″ of snow. Areas to our south and east could easily see ~12″ plus from this storm.
Timing looks like snow will begin ~11 AM as Virga, with snow making all the way to the ground ~12:30 PM once the air column is saturated. And, of course, the evening commute will be snowy and difficult. The Wednesday AM commute will be especially difficult with snowfall rates of ~0.4″ per hour, which is not anything you want to drive in if you can avoid it. Also, keep in mind, that the normal salts used for treating road surfaces do not work very well with temps in the single digits and low teens… Some snow crews will add calcium chloride to the mix, but most will be using the standard sodium/sand mix. Bottom line is that treated roads will still be slick.
You should monitor local media outlets for updates and additional warnings during the morning tomorrow, and be prepared for a long, difficult evening commute. Tune your NOAA All Hazards Wx Radio (that you all have, of course) to Channel 7 for any late-breaking changes…
I will be running the numbers tonight and again tomorrow morning and will send an update tomorrow morning.
Last storm was “one of those…” I originally was looking at a “coating to ~1” type of event. I then went into a long meeting and when I got a chance to have a look at what was going on a few hours later, I knew then that we were experiencing something called “entrainment.” That is when precip falls rapidly enough to pull cold air down from aloft, which turns everything to snow. It is also something of a self-reinforcing phenomena resulting in more precip that usual… Shrewsbury was on the apex of one zone that widened to our north east. The second zone was well to our south west. My update was ~4.7″ of snow, and we ended up with 5.5″ (official final from NWS). Some areas of Shrewsbury closer to Boylston got more snow (Boylston had ~8″ and Westborough had ~6.5″. Milford had ~3″ and Brookfield had ~1″).
Disclaimer:
My forecasts should not be used for anything other than general information.
You should not send my forecasts to others without this disclaimer attached
so that there is no chance of misinterpretation by others. Thanks!
Steve
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– Civilization exists by geological consent, subject to change without notice. –
