Sunday, March 3, 2019

Biggest Snow Storm Of The Season Heads To Impact Region Tonight

The National Weather Service (NWS) in Norton, MA has issued a *Winter Storm Warning* from 7 PM tonight until 10 AM Wednesday.  A widespread 6-10" snowfall is expected.  This storm will be the biggest of the season in Boston, surpassing the 3.6" on February 18.  November 15, 2018, is the high snow mark for Worcester and Providence so far this season.  7.8" fell in Worcester while 6" fell in Providence.  Both of those records should fall tonight/tomorrow morning, though Providence is more of a lock than Worcester. 

NWS Early Sunday PM Headlines
I've had a lot of questions from inquiring minds wondering what the deal is with this storm.  Let's answer in those in a Questions and Answers blog.

It's pretty nice this afternoon.  Is it really going to snow?
Partly to mostly cloudy skies will give way to all clouds later this afternoon, but before that happens, a few breaks of sun will help keep temperatures in the upper 30's and low 40's.   However, they will fall into the upper 20's and low 30's this evening.  It is not a classic "noreaster" set up because there is no cold Canadian high pressure to our north supplying the region with a fresh supply of Arctic air.  The first few hours of snow will fall with temperatures near freezing so expect so wet flakes to start.  By 1 AM, Worcester County will be in the upper 20's.  So it won't be a powder bomb like Thursday morning, but it also won't be a heavy wet "spring" snow either. 

What is the storm doing right now?
The storm is currently dropping snow across Missouri, Illinois, Indiana, Ohio, and Pennsylvania.  The south is seeing heavy rainfall and severe weather. 
WSI/Wunderground Intellicast National Radar 1215 PM
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The presentation on satellite is also impressive.  It is still in the process of maturing, but it is going to have the classic "leaf" or "comma head" by the time it is moving past Southern New England.

NOAA GOES EAST (16) Continental US IR Satellite 
At the surface, we see strong high pressure descending into the Upper Midwest and into the Great Plains.  The radar confirms the amount of precipitation available as this surface low works across the Southeast and starts to re-develop off the Mid-Atlantic coast.  

WPC Surface Fronts/Precipitation Sunday 1 PM
Okay cool, but when does it start?
Snow will begin to fall in Southwest Connecticut after 5 PM and will get into Worcester in Boston around 7 PM (give or take).  
16z HRRR Simulated Radar Sunday 5 to 9 PM (image WeatherModels.com)
As mentioned before, temperatures will be falling into the upper 20's in Northeast MA and Worcester County, so expect this to start sticking to untreated roads right away.  

When will the heaviest snow occur?
Expect snow to fall at moderate to heavy from 1 AM until 7 or 8 AM in Central Massachusetts, and until 10 AM in Eastern MA.  The majority of snow accumulation will fall during this time period and travel will be extremely difficult.  The low will deepen as it moves from the Mid-Atlantic coast to just Southeast of Nantucket. 

WPC Surface Fronts/Precipitation Monday 1 AM, 7 AM

I think 1-2"/hour snow rates are possible as the low gains strength and slides to our southeast.  This is likely in the region bounded by Boston, Worcester, Hartford, Providence, and Plymouth.  The most likely time for these intense rates would be 2-5 AM.  

16z HRRR Simulated Radar Sunday 9 PM to Monday 5 AM (image WeatherModels.com)
I see a sleet line in that radar loop.  Will I get all snow?
Almost everyone away from the Cape and Islands will see all snow.  Sleet will mix in up to Hartford-Providence-Plymouth line we just discussed.  

How much snow?
A general 6-10 inches.  The NWS is calling for 6-8" for almost all of the region.  Some of the higher resolution models are going for 8-12".  A few communities will see over 10" but I believe they will be the exception.  I do think a lot of towns come in around 7-9" so for insurance, 6-10" for all regions except those that mix with rain and sleet.  

NWS Snowfall forecast through Monday 1 PM (image WeatherModels.com)

What about the Monday morning commute?
Snow will still be falling at 7 AM in Central and Eastern MA and Rhode Island.  It will ease up by 10 AM.  With the bulk of the snow falling just before the commute, I expect a horrendous morning on the roads for those who have to be on them.

Will there be school?
I think most schools will close.  

Any further questions?
Leave in the comments on the Facebook page or @zgreenwx on twitter.  

-Zack Green

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