Winter Storm Watch Issued For Sunday, Heavy Precipitation Expected

The National Weather Service in Norton, MA has issued a *Winter Storm Watch* from Saturday afternoon through Sunday evening.  Expected hazards include snow, sleet, and freezing rain.

NWS Headlines 01.17.19 330 PM

Without further ado...

Short Term Forecast

Some light snow will move in tonight, with little to no accumulation.  There could be some slick spots on the road tomorrow but it should be no problem.  Temperatures will max in the upper 30's/low 40's and we might even see some sun by tomorrow afternoon.  Temps Saturday will be in the 20's as we set the table for the winter sandwich of precipitation that is to come on Sunday.

Part 1 Saturday 8 PM- Sunday 5 AM

Snow begins to fly after 8 PM Saturday night.  Most of Southern New England is snowing by 10 PM, with the exception the immediate South Coast, Cape, and Islands where it will mix/rain.  Snow intensity peaks between 11 PM and 4 AM in Northern Rhode Island and Southern Worcester County.  By 3 AM, sleet, freezing rain, and rain will begin marching north through CT/RI/and SE MA.  Snow will begin to change to sleet and freezing rain in Northern RI/Southern Worcester County after 4 AM, with a complete change over by 5 AM.

12z ECMWF 1 hour precip type/MSLP Saturday 6 PM- Sunday 5 AM (image WeatherModels.com)

The majority of the snow that will fall in Central and Eastern MA, RI, and CT will fall during this overnight time frame.  Expect 5-10" with higher amounts near and north of Worcester and lighter amounts closer to Providence. 

Part 2 Sunday 5 AM- Sunday 5 PM

Periods of sleet, freezing rain, and rain.  The rain is likely confined to Norfolk, Bristol, Plymouth, Barnstable, Dukes, and Nantucket counties in MA as well as most of RI and SE CT.  Elsewhere, there is a 30% chance of at least 0.25" of ice accretion from freezing rain for a good swath of CT, RI, and MA.

WPC Freezing Rain Probability 24 hours prior to Sunday 7 PM

This is significant threat to travel and the power grid.  Snow is one thing, sleet is a bit annoying as it increases the weight to plow/shovel/snow blow, but freezing rain can cause long duration power problems.   Winds will gust 20-35 MPH during the day when this freezing rain is falling.  That isn't a big deal usually, but when trees and power lines are being weighed down by ice it becomes a greater issue. 

12z ECMWF 1 hour precip type/MSLP Sunday 5 AM- Sunday 5 PM (image WeatherModels.com)

Now there is hope that this model is overdoing the freezing rain and just get a sleet bomb out of this.  The American NAM model has lots of sleet and just a narrow band of freezing rain.  Either way it will be slippery, sloppy, and messy, but we won't have to deal with damage to the power grid in a sleet storm.  Somebody, even if it is localized, is going to get a long ice storm out of this I am afraid. 

Part 3- Sunday Evening-Monday

The system will end with 1-3" of snow and temperatures falling into the single digits/below 0 as we settle in to watch the AFC Championship Game. 

Takeaways

Be prepared to lose power for a few days.  It will be brutally cold on Monday and Tuesday.  Then root for sleet or rain instead of freezing rain.  We'll talk tomorrow and I can take questions after 8 PM on my Facebook page.

-Zack Green