Hey, kids: Boston public schools closed tomorrow

From the Storm Prediction Center http://www.spc.noaa.gov/products/outlook/day1otlk.html (time sensitive link)

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0654 PM CST Wed Mar 07 2018

Valid 080100Z - 081200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
A few lightning strikes remain possible over southeastern New
England this evening.

...Discussion...
A powerful mid-latitude cyclone continues to mature along the East
Coast this evening, with a classic comma-head presentation on
satellite imagery. Within the approximate 850-700mb warm conveyor,
strong ascent is aiding banding of heavy precipitation across parts
of southeast New England. Additionally, steep mid-level lapse rates
(associated with the mid-level dry slot wrapping into southern New
England) are maintaining very weak elevated buoyancy. Indeed,
KBOX/KOKX ZDR data continue to highlight depolarization (related to
a strong electric field) from Connecticut to southeastern
Massachusetts. Therefore, embedded convective elements may still
yield a few lightning strikes over southeast New England this
evening.

..Picca.. 03/08/2018

P.S.: This is a picture of the storm, as of a little while ago. You can see why they think there might be another storm around Monday:

https://cdn.star.nesdis.noaa.gov/GOES16/ABI/CONUS/GEOCOLOR/20180670112_G...