Moderate Snowfall for Southeastern New England

The trend so far this winter season has been low pressure systems to track through the Great Lakes.  This track helps develop a new low pressure system near the Mid Atlantic coast.  Although there has been some Arctic air in place at times it is unable to hold and low pressure tracks over SE MA changing precipitation quickly from snow to rain inside 495 and south of the Pike,  Hartford and Worcester are at or near average when it comes to snow to date.  Coastal Boston and Providence have switched to rain much more frequently then the interior Worcester and Hartford.

The snow this AM and tomorrow's  storm will help change that.  A wave of low pressure will deepen as it passes south and east of New England on Saturday.  This event will produce 3-6" of snow across Worcester, Middlesex, Essex and Suffolk counties in MA and Northern Providence County in RI.  A larger swath of 6-10" is likely across Norfolk, Bristol, Plymouth and Barnstable counties.  A foot is likely on Martha's Vineyard and Nantucket.  6-10" is also likely across Kent, Bristol, Washington and Southern Providence counties in Rhode Island.  Snow begins late morning and ends before midnight.  

General Overview
The National Weather Service has issued a *Winter Storm Warning* for much of Eastern MA and all of RI.  A *Winter Weather Advisory* is up in NE CT, Southern Worcester County and the rest of Eastern MA.  The trend has been west today so it is conceivable that these all shift further west by tomorrow AM.

NWS Boston Headlines Friday PM 

 Temperatures tonight will drop into teens tonight.  Clouds will increase as the low moves northeast which will prevent temps from dropping into the single digits.  Notice how widespread these are in New York and the Northern New England states.

NWS min temps Saturday AM (image Weatherbell)

Temperatures will warm into the upper 20's/low 30's in SE MA and the Cape/Islands.  Temperatures stay in the teens and low 20's outside of SE MA.

NWS Max temps Saturday (image Weatherbell)

Track and Timing
Here is the surface chart evolution of the storm system.  The low will collect moisture in the Gulf of Mexico and bring winter weather into the South.   From there it will move south and east of New England and gain some strength as it does.

There are winter storm warnings in GA, TN, SC and NC all the way into Southern New England.

NWS Eastern Region Headlines

Snow will break out between 10am-noon The heaviest snow in Central MA is in the 1-7 PM window.  Conditions in SE MA deteriorate after 1 PM.  There will be a few breaks in the snow towards dinner time for some.  Snow will pick up in intensity again around 8 PM before tapering off after 11 PM.

18z NAM hires 4km sim radar Saturday 11 A, 3, 8, 11 P (image Weatherbell)

 Snow Totals
The highest snow totals in Worcester from a single storm are 6.0 on December 17 and 5.9 on December 29-30.  Worcester may tie this given the cold temperatures and associated "fluff factor" that comes with the snow.  4-6" sounds good in Southern Worcester County but a 20 mile shift west and that becomes 6-10".  I think most of the snow piles up in the early PM and then again around 7-9 PM.  Much more precipitation will fall in Southeastern MA but temperatures will be close to freezing.  I do fear some power outages as winds gust to 40 in SE MA with a foot of snow.

NWS Snow forecast next 54 hours (image Weatherbell) click to enlarge

Some models have more snow in Worcester County and this seems like it should be an over-preformer given the cold in place in CMass. If that happens we are looking at these numbers.  But remember snow lovers the NWS numbers are more likely.

NWS Boston max potential snow Saturday storm

I'll update in the morning.

-Zack Green