1-02-2018: Thursday (Jan. 4) Storm Update #2

Good evening!!

A number of things have changed with our storm for Thursday as a westward trend continued today. Let’s look at each detail.

Timing
This storm has a pretty high chance of wrecking your Thursday plans, with snow starting in the late overnight and early morning hours on Thursday. Heavy snow will fall throughout the day and end late evening to early overnight Thursday night.

Snow
The trend west has resulted in more precipitation being forecast. With similar temperatures holding in the forecast resulting in higher snow to liquid ratios, the snowfall forecast has increased significantly. A widespread 6-10″ of snow is likely in eastern Massachusetts, southern and east-central New Hampshire, a large part of Maine, eastern Connecticut and much of Rhode Island.

An area of 10-12″ snow is looking likely as the “jackpot” region with the best blend of precipitation and snow ratios, and I believe this area will be in northeastern Massachusetts and southeast New Hampshire, including Dracut and generally covering the Boston to Manchester corridor, its vicinity, and points east. This is not to say that amounts over 10 inches won’t happen further south – they very well could – but I didn’t feel comfortable extending the new zone into northern sections of southeast Massachusetts, where there will be more precipitation but slightly warmer temperatures at all levels resulting in slightly lower snow ratios. It is possible that this zone may need to be expanded and/or modified in both area and amount of snow, so stay tuned.

Further west, I am forecasting 3-6″ of snow in western Massachusetts, western New Hampshire, most of Connecticut, and southern Vermont, where less precipitation will take place (perhaps a lot less) but colder temperatures at all levels will aid snowfall totals. West of that, the snow will generally be sub-advisory level. I am also forecasting 3-6″ for most of Cape Cod and the immediate south coast of Massachusetts, and 1-3″ for Nantucket, Martha’s Vineyard and portions of Cape Cod, where mixed precipitation will be an issue.

snow map 2018-01-02 500P.png

Wind
This could be the bigger issue with the storm, which is saying a lot. Wind gusts of 40-50 mph are likely for the Dracut area. Higher wind gusts over 60 mph are possible closer to the coast, with lower wind gusts further inland. This, plus heavy snow, will produce blizzard conditions at times. (More on the “bigger issue” thing in a minute.) An additional slight westward trend could nudge these wind amounts higher, while a slight eastward trend would nudge them lower. (At this point, an eastward trend appears unlikely and all data supports either a continued westward trend or a near steady storm track forecast.)

Impact
Heavy snow will combine with strong winds to create very hazardous travel conditions, with not only the classic snow-related travel issues, but also blizzard conditions being possible at times. Travel will be extremely difficult on Thursday as a result, and if the forecast holds, it is advised that any unnecessary travel be avoided. Power outages are also possible considering the strong winds.

The National Weather Service has issued a Winter Storm Watch and a High Wind Watch, previously only issued if mixing would interrupt blizzard conditions for several straight hours, but now with the Blizzard Watch being eliminated, the combination screams “blizzard possible”, because the standards for a High Wind Watch/Warning are a little tougher on the wind side than the Blizzard Warning: 40+ mph sustained for at least one hour and/or any gusts exceeding 58 mph for the High Wind alerts, and sustained winds of 35+ mph and/or frequent gusts of 35+ mph for the Blizzard Warning. So meeting blizzard criteria certainly isn’t out of the question at all in Dracut, but the coast definitely has a better chance. (In addition to the wind requirement, you also need visibilities below 1/4 mile, and both the wind requirement and visibility requirement must be met for three straight hours.) Blizzard or no blizzard, a significant storm awaits.

Have a great night! More on this tomorrow morning.
-Nathan

 

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