This Is Not A Recording; Snow to Ice to Rain Tonight

Stop me when you've heard this forecast lead before; a fast moving winter storm will start as snow tonight before changing to sleet, freezing rain, and plain rain after midnight.  Light snow and ice amounts are expected but the Thursday AM commute is likely to be slippery in Central, Metrowest, and Northeast Massachusetts.

NWS Headlines
The National Weather Service in Norton, MA has issued a *Winter Weather Advisory* from 7 PM this evening until 7 AM Thursday morning for all of Southern New England except for the Cape and Islands. 

NWS Boston Headlines 

A Winter Weather Advisory means periods of snow, sleet, and freezing rain will cause travel difficulties.  Expect slippery conditions and use caution when driving. 

General Overview
Strong high pressure is control today.  Temperatures started in the single digits and teens and they will rebound in the low to mid 20's.  Fun fact- the jet stream is ripping along above our heads.  A flight was measured at 801 mph as it got embedded in 200+ mph winds around 35,000 feet up.  This is good if you are flying to Europe, bad if you have to fly to the west coast.

00z EURO 300 mb winds Tuesday 7 PM (image WeatherModels.com)

The fast jet will keep traffic in the atmosphere moving along.  The high pressure will slide east today as a storm system develops along the Gulf Coast, lifts northeast, and reforms near the Mid-Atlantic coast.  High level clouds will increase throughout the day, but precipitation will hold off in Central and Eastern MA until after 7 PM.

WPC Surface Forecast Fronts, Precipitation Wednesday 1 PM, 7 PM, Thursday 1 AM, 7 AM

Cold surface temperatures will linger in Central and Northeast MA all night so it is likely that all precipitation that falls will be frozen north of a Brockton to Foxboro to Smithfield, RI line.   However, temperatures on Thursday will rise into the 40's across most of Southern New England so we aren't worried about everything turning to cement.

Timing/Impacts
Snow will begin after 7 PM in Worcester and Boston.  Snow will be light from 7 until 10, increasing around 11, and peaking from 12-2 AM.  Between 2-3, snow will transition to sleet, freezing rain, and rain.  All precipitation ends around 6 AM. 

12z HRRR Simulated Radar Wed 4 PM to Thur 7 AM (Image WeatherModels.com)

Although surface temperatures will be in the mid 20's across Central and Northeast MA, warm temperatures aloft will limit the ability for snow growth in the mid layers, limiting snow totals on the ground.  That said, a general 2-4" is likely followed by up to 0.10" of ice.  Some communities closer to the NH/MA border could see up to 4". 

12z HRRR total snow *click to enlarge (Image WeatherModels.com)

For the Thursday AM commute, traffic is lighter than normal this week thanks to school vacation.  That will help keep congestion down, but it will still be a slow go.  Unlike last weeks storm, precipitation will end closer to 6 AM, which will delay the clean up.  I anticipate the main roads being fine, but untreated side roads will be slippery.  If you have the option to work from home, it is a not a bad idea to exercise that right.  The roads will be fine by the afternoon, but why spend the time commuting when you can be working? (Practicing for my boss). 

I will update again if needed.

-ZG