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

Friday, March 1, 2019

Two Rounds of Snow On The Way To SNE

A quick hitting storm will bring plowable snow to Southern New England on Saturday.  A second storm will bring even more significant snow  overnight Sunday into Monday morning.  Let's get into it.

Headlines
A *Winter Weather Advisory* is in effect from 1 AM Saturday until 7 PM Saturday.  The heaviest snow will fall in the morning, with a break mid to late afternoon.  A second batch of light to moderate snow will move through Saturday evening. 

NWS Early PM Headlines 
Saturday Storm
There will be no issues this evening.  Temperatures will be in the mid to upper 20's.  Temps in Northern RI, Central, and Northeast MA (including the city of Boston) will be in the mid to upper 20's  tomorrow morning.  From Providence to Plymouth south and east, temperatures will be in the low 30's.  This means that the snow will be a bit fluffier the further north and inland you go, and wetter and heavier the further south and east you get.
WPC Surface Fronts/Precipitation Friday 7 PM, Saturday 1 AM, 7 AM 

Snow will reach Southern Worcester County after 4 AM.   The snowfall intensity will pick up between 7 AM 12 PM.  Snow showers will linger Saturday afternoon in Central MA, while steady snow will continue in SE MA and RI until the mid to late afternoon. 

18z HRRR Simulated Radar Sat 3 AM to  Sunday 1 AM (image WeatherModels.com)

Snow accumulation will be highest south and east of Hartford, Worcester, and Lowell.  The jackpot will likely be somewhere from Providence to Plymouth.  In the Blackstone Valley, expect 3-5" of snow. 

NWS 48 hour snow forecast through 1 PM Sunday (image WeatherModels.com)

Sunday
Sunday will actually be pretty nice, although there will be snow on all the sidewalks and lots of puddles from some of that snow melting.  The March sun angle is quite strong so even with temps "only" in the upper 30's, it will still feel comfortable.  It is all a tease, as the morning sun will give way to increasing high clouds as the next storm approaches. 

Sunday Night-Monday Storm
This storm will start as snow for everyone.  Snow will begin after 7 PM, with snowfall rates increasing after midnight. 

12z EURO Precipitation Type, MSLP Sun 4 PM to Mon 11 AM (image WeatherModels.com)

The EURO model drops 4-8" of snow before changing to rain inside 495 and south of the Mass Pike, including the Blackstone Valley.  Other models have more snow.  There is still plenty of time to evaluate the precipitation type for this one.  It will definitely begin as all snow and even if it does turn to rain, the morning commute is going to be a mess.  The good news is, this system will be gone by lunchtime.  

Opening bids for snowfall accumulation is 5-10" in the Blackstone Valley, with highest totals outside 495 and north of the Pike.  

More to come this weekend.

-ZG

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 widesprea...