Saturday, November 19, 2016

Showers Saturday Night-Sunday Ending as Light Snow

A vigorous low pressure system is delivering the first widespread snowfall of the season to the Midwest and Great Lakes,  As the system moves east it will bring snow to the interior Northeast including the mountains of Western New England.  In the urban corridor of Southern New England we will see mostly rain but it will end as some light snow showers Sunday evening.  Little to no accumulation is expected.

General Overview
The IR satellite shows the storm in the Great Lakes.  There is also another storm moving into the NW US and low pressure offshore of New England.
NOAA/NWS/NCEP Rainbow IR satellite 
The low in the Atlantic is responsible for gray skies in Southeastern New England as it slowly spins offshore.  The system in the Great Lakes will push this out to sea as it moves towards the coast this weekend.  Here is the surface chart as of 7 am.
WPC Surface Analysis 7 AM
Temperatures are crashing behind this front.  Here the 24 hour temperature difference for the US.  Temperatures are running over -30 F cooler at this time today when compared to yesterday in the Central US.
US 24 hour temperature difference (image Weatherbell)
A significant lake effect snow event will take place in Western NY/PA.  Cold Canadian air blowing over the relatively warm Great Lakes is a favorable set up for heavy snow in this part of the country.  In this radar image of the Great Lakes the leading band is heavy rain which lines up well with the surface cold front.   The precipitation in Michigan is lake effect snow.
NWS Great Lakes Regional Radar 
A secondary surface low will form near the Southern New England coast this evening.  Maximum temperatures today are in the 50's.  It will be cooler in Eastern MA thanks to the cloud cover and warmer in Western MA thanks to more sunshine.  A mix of sun and clouds is forecast in Central MA.  Everyone in SNE is way too warm for snow at the beginning.
NWS max temps Saturday (image Weatherbell)
We should see some pockets of light showers and drizzle this evening.  Steady rain works into CT/W MA after 10-11 PM and through Central/Eastern MA/RI around 1-2 AM.   Here is the surface map at this time.
WPC Surface fronts/precipitation 1 AM Sunday
Here is the simulated radar for 4 AM.  The low is rather weak so I don't expect a ton of rain tonight.
12z NAM hires simulated radar Sunday 4 AM (image Tropical Tidbits)
The low will gain strength as it moves into Northern New England which will contribute to heavy snow in the Green Mountains.  As the low deepens winds will increase across SNE blowing upwards of 40 MPH.  We don't expect Sunday to be a washout but it will be cold with a stiff N/NW wind and off/on showers.  By around 5-6 PM Central MA/N RI/CT can start to see snow showers.  First here is expected precipitation through Monday 1 AM.
NWS precipitation forecast through Monday 1 AM (image Weatherbell)
Here is the simulated radar for Sunday 7 PM.
12z NAM hires Simulated Radar Sunday 7 PM (image Tropical Tidbits)
Max temperatures tomorrow occur early before dropping in the afternoon.  Expecting around 40 for most.
NWS Max temperatures Sunday (image Weatherbell)
We drop into the mid 20's Sunday night.
NWS minimum temperatures Sunday night-Monday am (image Weatherbell)
As for total snow accumulation
NWS total snow accumulation through Monday 7 PM (image Weatherbell)
So as you can see my teacher friends you have to make your lunch and grade your papers tomorrow.

Zack Green

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