Evaluating the Storm So Far

There is already 2-4" of snow on the ground across portions of Southern New England, including my front walk.  The storm has not really developed yet and this is still the initial surge of precipitation.   On satellite, we do not yet see the classic comma head that most Nor'Easters have.
NOAA/NWS/NCEP GOES_East Rainbow Satellite 1245 PM
Outside of the immediate coast and the Cape and Islands, this storm is mostly snow at the moment.  Light precipitation began between 10-11 AM.  Snow began to stick around noon time so we are on an inch per hour pace at the moment.
NWS Northeast Regional Radar 208 PM
There really isn't much to look at on the surface chart right now.  A weak low-pressure system in Western PA and the DMV is only at about 1005 mb.  This is resulting in the fragmented precipitation shield.
WPC Surface Analysis Sunday 1 PM
A *Winter Storm Warning* remains in effect until 7 PM Monday for most of MA.  A*Blizzard Watch* is posted for coastal MA and the Cape and Islands from 4 AM to 7 PM Monday.  The NWS Headlines Map has a lot of hazards highlighted.
NWS Early PM Headlines
In the next 3-4 hours expect moderate to heavy snow accumulating 1-2" per hour,  Temperatures in Central MA are still in the 20's so the snow is still light and fluffy.
19z HRRR 2 m temps 2 PM (Image Weatherbell)
These temperatures will slowly increase this evening, topping out around 31-32 in Worcester County.  It will likely be a few ticks warmer in Eastern MA.  So the consistency of the snow is cement in CT.RI, and E MA but not so bad in C and W MA at the moment.  Here is the projected radar for 7 PM.
19z HRRR sim radar Sunday 7 PM (image Weatherbell)
The low at 7 PM will be south of New England, near Long Island with a pressure of 997 mb.  A low tracking will send keep the wind out of the east so temperatures will stay in the low 30's until the pre-dawn hours.  The snow in Central MA will go over to cement like during this time period.
WPC Surface Fronts/Precipitation Sunday 7 PM
The snow may let up a bit in Central and Western MA between 9 PM and 2 AM.  Boston will keep cranking as the low undergoes bombogenesis.  We are looking at a weather bomb folks, right off the MA coast!!  The 1 PM pressure is 1005 and it should be down to 973 by 1 PM tomorrow, a greater than 24 mb pressure drop in 24 hours.  Here is the radar at 5 AM.
19z HRRR Sim Radar Monday 5 AM (image Weatherbell)
Snow lets up just after 7-8 AM in Central MA. Snow will last into Monday afternoon in Eastern MA and the Cape and Islands with high winds.  The pressure by 7 AM is down to 978 mb.
WPC Surface Fronts/Precipitation Monday 7 AM
As for my snow totals, I will bring them down slightly.  Instead of 14-20 it is 12-16, 10-14 is 8-12 now etc.
Now let's talk about the winds.  They will really begin to increase after 4 AM.  Winds gusts over 40 MPH are likely until early Monday evening.  Any snow that falls Monday will be wiped through the air.  Temperatures will be in the upper 20's Monday.  The winds will make it feel like the teens.  The outer Cape, Cape Ann, and Nantucket will see winds approaching 60 on Monday.
NWS Max wind forecast Monday 4 PM
 The wind finally lets up after 10 PM tomorrow evening.  The reason for the long duration wind barrage is a 973 mb low to our east and a 1029 mb high to our southwest.  The atmosphere is squeezing a lot of air through the region.  There will be power outages throughout New England.
WPC Surface Fronts/Precipitation Monday 1 PM
At this point Winter Storm Orson will look gorgeous.  The weather geek in me wishes that low was 40 miles southwest but that would be a devastating storm in Southeastern MA.  Portland, ME will really get pounded.  Tomorrow would be a fun day to be at Nubble Light in York, ME.

-Zack Green


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