Minimal Snow Threat Saturday in SNE, Sunday??

High pressure is in charge today but it will shift offshore tomorrow as an approaching clipper dives south of New England.   While there may be some light snow tomorrow, it will struggle to accumulate on the roads.  A more interesting scenario is in play late Saturday night into Sunday.   The clipper will "explode" as it reaches the Gulf Stream.  These systems love strong thermal gradients and really develop when they encounter one. How far north/east this happens will determine how much, if any, snow will fall.

General Overview

Here is the forecast surface map as of 8 PM tonight.  

WPC Surface Fronts/Precipitation Friday 8 PM

Cloud cover will be minimal tonight and winds will be light.  The clipper will slide south and east as the NW floor keeps a cold, dry Canadian air mass in place.  The deep snowpack across the interior will work with the dry air, clear skies, and light winds to drop temps into the single digits.  Closer to the big cities temperatures will drop into the teens.

NWS Minimum Temperatures Saturday AM (image Weatherbell)

Clouds will increase on Saturday and most of the day will be gray.  There might be a few light snow showers.  I can't see any snow sticking before sundown, except in the highest elevations in Western MA and Northern Worcester County.  Even there it would be a coating if that.  Temperatures tomorrow afternoon will be in the mid to upper 30's across Worcester, Middlesex, Essex, Suffolk, and Norfolk counties.  In SE MA/RI max temps will get into the low 40's.

NWS Maximum Temperature Saturday PM (image Weatherbell)

Things will get interesting Saturday Night.  This is when the clipper low will begin transfer into an extratropical ocean storm.  At a minimum, a period of strong winds will occur over the Cape and Islands as the surface low develops.

WPC Surface Fronts/Precipitation Saturday 8 PM

Any precipitation would not stick until after midnight in RI/ E MA.  Temperatures will be dropping into the mid 20's by Sunday AM.  A couple of bands of snow are possible if the low forms closer to SNE.  If that were to occur, 1-3" would be possible from Hampton Beach -Fitchburg - Springfield -Fairfield south and east and perhaps 3-6" for SE MA and S RI,  The most likely solution is generally 1-2" South of the Pike and 2-4" S coastal MA and the Cape/Islands.

NWS Snowfall Accumulation Sunday 2 AM to Sunday 2 PM

 I'll be out of town until Sunday AM, but I will try to get some information up tomorrow if a trend to the North happens and it looks like we get more snow.

-Zack Green

Wrapping Up Stella, Looking Ahead

It is still snowing in Burlington, VT where 28.7" of snow had fallen as of 10 AM.  Binghamton, NY has over 31" of snow which is the greatest 24-hour snow total on record.  The low moved over Southern New England which shifted the truly epic snow totals to Western MA, Eastern NY, Northeast PA, and Western VT.   Snow changed to sleet in South Central MA at 3 PM and rain around 5 PM, but after around a foot of snow fell.   Snow fell fast and furious between 10 AM and 3 PM when snow rates were 2-3"/hr.  Widespread 12-18" and 18-24" forecasts didn't really pan out for many so this storm can be considered a bust in Boston and some other areas of Eastern MA.  As a weather forecaster, the sleet/rain/wind angle was underplayed for Southeastern New England.

NWS SNE Snow Totals Winter Storm Stella

Looking at that map I just wish I moved the 8-12 back into Middlesex and Worcester County but overall I think I did okay with snow totals.  Blizzard conditions verified at Lawrence but that was the only location in Southern New England.  For March, this was a nice storm.  It ended in the top 6 in Hartford and Worcester, the two inland Southern New England climate sites.  6.6" fell in Boston and 3.3" in Providence.

NWS Boston top 1 day March Snowstorms

 Around 50K customers were without power at the as the low crossed the Cape yesterday afternoon.  The pressure dropped to around 980 mb.  I know some people have 6th weather sense where they feel pain in their joints when rapid pressure changes occur.

WPC Surface Analysis Tuesday 5 PM

A list of wind damage and snow totals can be found at the National Weather Service homepage.  The track brought a surge of warm air into SE New England.  The computer models showed some historic potential with this storm so I think we (as meteorologists) were right to talk this storm up.  The track clearly shifted west on Sunday and so did the historic potential.  Forecasters were slow to shift to this track.  One simple change is to just be conservative with snow numbers.  Snow lovers don't care if a storm under performs.  Forecasting something that has rarely happened sets one up for failure.  Another problem is communication,  99% of the time that is the fault of the scientist trying to explain to the non-scientist but sometimes you listen to people talk about the weather like...

Not an original idea, H//T Matt Lanza twitter

There are a lot of places to get information so I will continue to try and be as clear and direct as possible, while also conveying the uncertainly of weather forecasting.

Wednesday-Thursday Forecast
Clouds will increase this afternoon and there is a slight chance for a snow shower between 4-7 PM.   Western and Central SNE have the best chance to see some flakes. Winds are out of the west at 10-15 MPH with gusts to 25.  Max temps will be in the upper 20's and low 30's.

NWS Max Temps Wednesday (image Weatherbell)

Despite the low temps the March sun will help melt some snow and it will feel okay when the wind is not blowing.  The clouds will clear up overnight so lows will fall into the teens tonight.

NWS Minimum Temperature Forecast Thursday AM (image Weatherbell)

Counter clockwise flow around low pressure in the Canadian Maritimes (Stella) and clockwise flow from high pressure descending into the Southeast will keep temperatures well below average tomorrow.

WPC Surface Fronts/Precipitation Thursday 8 AM 

Max temps might be a little warmer, but still cold tomorrow.

NWS Max Temperatures Thursday (image Weatherbell)

It will be windy again tomorrow.  I'm keeping an eye on some snow this weekend.  Saturday looks like light snow showers with temperatures in the mid 30's.  Sunday could be interesting if this storm slows down a bit.  Some plowable snow is possible in SE New England, but I'm not overly impressed with the setup.

-Zack Green

March 2017 Blizzard- Live Blog

(This post will be updated all day with storm coverage.  Please send photos, questions, comments, and complaints to zgweather@gmail.com or https://www.facebook.com/ZgWeather.  The latest entry will be posted first.)

Post 15 3:26 PM
I'm running on fumes right now so I'm going to take a nap.  I have no interest in light rain, freezing rain, and sleet.  Thanks for following along today.  I'll post a wrap up tomorrow in a new blog.

Post 14 2:12 PM
Thundersnow reported to the east of Worcester in Littleton area.

Post 13 1:26 PM
It looks like the change to sleet/rain holds off until 5 PM.  Also, another 1" possible at the end of the storm!

16z HRRR Sim Radar 5 PM (image Weatherbell)

16z HRRR Simulated Radar 10 PM (image Weatherbell)

Still 3-5" to go

Post 12 12:30 PM
Latest totals from NWS Boston

Post 12 12:09 PM
This may be my last post.  The lights are flickering and power outages just jumped 12k in 15 minutes.

Post 11 12:02 PM
Power outages picking up.  Most are in Worcester at the moment, but these will grow.  Charge up the cell phones!  This is from National Grid.

Post 10 11:37 AM

Post 9 11:27 AM
Some more totals coming in.

via NWS Boston

Post 8 10:26 AM
Accident on Rt 6 in Yarmouth

Post 7 10:00 AM
Here is the latest as of 10 AM

• Blizzard Warning remains in effect for interior Southern New England.  Winter Storm and High Wind Warnings are posted in SE MA and RI.
• Generally 4-6" in Western MA and parts of CT, 2-4" in Central MA and 1-2" in Eastern MA
• Heaviest snow begins NOW through 3-4 PM 
• A change to rain will limit snow totals south and east of Worcester
• Damaging winds possible this afternoon.  You will notice an increase over the next few hours

Post 6- 9:30 AM
The worst of the storm is now approaching.  I've already seen the chatter on twitter about how this storm is a bust.  Well, some totals may end being a bust but most meteorologists in Southern New England did advertise the worst of the storm being between 10 AM - 3 PM.

NWS Northeast Regional Radar loop

The rain/snow/mix line is where the bright yellows and orange meet the lighter greens to the north.  It is above freezing a few thousand feet above our heads in these regions.  This is why we will mix later this afternoon.

12z HRRR 850 mb temps 8 AM (image Weatherbell)

Post 5- 8:50 AM
Hubbardston, MA police just posted this photo on twitter.  Keep the speeds down.

Post 4- 8:30 AM
The central pressure is down to 990 mb.  There has been a 7 mb pressure drop in the last 2 hours just off the Mid-Atlantic coast.

SPC mesoanalysis MSLP, Surface Wind, Radar 8 AM 

There is a lot of sleet mixing in with the snow near I-95 in the Mid-Atlantic.  NYC, Philly, and DC are all going to go well under their forecast snow totals thanks to sleet.  SE MA, S RI, and Coastal CT will have to deal with this later.

Post 3- 8:00 AM
The snow hole will shrink quickly in the next 1-2 hours.  Moderate to heavy snow is lifting north into Southern New England.  The precipitation will intensify as the low continues to strengthen and lift NE.

This satellite image is gorgeous.  Excuse me, I need a moment.

NWS/NOAA/NCEP GOES Water Vapor Satellite 715 AM

Post 2- 7:37 AM
Snow reports are starting to filter in already.  Approaching 5" in CT as of 730 AM.

Post 1- 6:56 AM
Good Morning Southern New England!  Jim Cantore is in the Blackstone Valley today.  He reports 1" in Millbury near the Pike.   Jim is saying "Millbury" correctly but I think we all know some locals who refer to it as "Millbree".

The first flakes started flying between 2-3 this morning.  The real snow band moved through between 5-6 AM.  Snow is filling once it gets to Northern RI but there is a gaping hole in the radar across SE MA/RI.  Don't worry, there is plenty to come.  This looks more like a decaying tropical cyclone moving up the coast (like Irene) than a Nor'easter.

NWS Northeast Regional Radar 

The low is beginning to "bomb" and its right offs the Delmarva.  This simulated radar looks good for the rest of the day.

09z HRRR Simulated Radar 6 AM to 11 PM (image Weatherbell)

Snow totals are impressive from this model run.

09z HRRR 18 hour snowfall totals through 11 PM (image Weatherbell)

More to come.

Winter Storm Stella- Timing, Impact, Totals

Good afternoon everyone.  Stella is on her way and she is poised to be a disruptive winter storm.  Snow flies before dawn and sticks right as the morning commute begins to get heavy if anyone is actually on the road tomorrow.  Snow will rapidly accumulate beginning mid to late morning.  Winds will gust over 35 MPH beginning around 10 AM and they will increase to 45-60 MPH Tuesday afternoon.  Coastal MA/RI/CT will likely see winds approach 65-70 MPH.  Snow rates will increase to 2-4"/hr between 11 AM and 5 PM for much of Western, Central, and Northeastern Massachusetts.  Northern RI will also see incredibly intense snowfall rates.  Snow lessens Tuesday evening and we are left with isolated snow showers on Wednesday.

If only we could all have this much fun in the snow

Most of the "Hall of Fame" level New England snowstorms are long duration, 15 round Ali-Frazier level boxing matches.  This storm is much more like Amanda Nunes beating the hell out of Rhonda Rousey in 48 seconds.  It may be brief, but we are going to know Stella was here.

NWS Headlines
The National Weather Service has posted a *Blizzard Warning* for much of Massachusetts, Northern RI, and most of CT.

NWS PM Headlines

A *Winter Storm Warning* is posted for Southern RI and SE MA (including Boston).  A *Winter Weather Advisory* and a *High Wind Warning* exist for the Cape and Islands.

General Overview
Stella is about to re-develop near the North Carolina coast.  Surface pressures have been falling near the Appalachians as the parent vortex begins to transfer its energy to the ocean side of the mountains.

NWS/NOAA/NCEP Rainbow IR satellite 245 PM

At the surface, low pressure in the Gulf is adding moisture to the system.  Meanwhile, strong high pressure is the dominant weather feature in Southern Canada/Northern US.

WPC Surface Analysis Monday 2 PM

The true impact of the high is to produce temperatures cold enough for snow.  Here is a look at the minimum temperature forecast tonight across the lower 48.  These are 5-10 below average for this time of year in the northeast.  That high will also help strengthen the low-level jet stream tomorrow, which will lead to the damaging wind potential.

NWS National Minimum Temperature Forecast Tuesday

.   The presence of energy in the Gulf of Mexico will arm Stella with plenty of moisture as she makes her way up the coast tomorrow.  Warm moist air will flow over the cold air entrenched in the Northeast.  This is a very efficient snow making process.  Another efficient precipitation process will be the presence of a very tight temperature gradient near the coast.  For example, it might be 44 in Hyannis and 26 in Worcester.  The low will also undergo "bombogenesis" as it moves up the coast (greater than 24 mb drop in 24 hours).

Storm Timing/Impacts
The first snowflakes will arrive in MA from SW to NE between 5 and 8 AM.  Here is how the low will evolve at the surface starting at 2 AM tonight, going in 6-hour increments.

WPC Surface Fronts/Precipitation Tuesday 2 AM, 8 AM, 2 PM, 8 PM

Temperatures will be in the mid to upper 20's for those north of the pike and outside 495.  Temperatures will warm to near 32 in Southern Worcester County and around the Pike in Eastern MA.  It will be warmer in SE MA.

NWS Max temperatures Tuesday (image Weatherbell)

Snow rates will be 0.5-1"/hr between 6-9 AM.  Between 9 AM-3 PM, Stella really begins to crank out snow.  At 9 AM there will be 2-4" (at least) of snow on the ground across the region.   Here is the future radar for noon time tomorrow.

12z NAM hires 3km sim radar Tuesday 12 PM (image Weatherbell)

Visibilities will drop to under a quarter mile by 9 AM, but when this band comes through they will be 0.1 of a mile or less.

12z NAM hires 3km visibility forecast Tuesday 12 PM (image Weatherbell)

At the same times, winds will be peaking around 50-55 MPH across much of the interior.  At the coast winds near 60-65 MPH and on Nantucket winds may gust to near 75!

12z NAM hires 3km surface wind gusts, mph Tuesday 12 PM (image Weatherbell)

The heaviest snow continues until around 3 PM-5PM when some sleet may mix in all the way to 495 and the Mass Pike as the low crosses Cape Cod.  The sleet may also mix in briefly in the Blackstone Valley.  Still, we will finish with another 1-3" as temperatures crash when the low moves into the Gulf of Maine.  Stella will feature a very strong band of winds a few thousand feet up in the atmosphere.  When the low crosses SNE this wind will be out of the east which will warm a few layers of the atmosphere.  That will be enough to turn parts of SE MA over to plain rain, albeit with very strong wind gusts.  

Precipitation ends in Southern New England by 8 PM.  Temperatures drop into the teens by Wednesday AM.  So first, here is how much precipitation is expected to fall.

NWS/WPC precipitation forecast through Wednesday 8 PM (image Weatherbell)

Out of all of that, here is how much snow the NWS expects.

NWS Total Snowfall forecast through Wednesday 8 PM (image Weatherbell)

That is probably a bit high in Southeastern Worcester County as the sleet will make that more like 14-15".  That said if it stays all snow then yes, expect 14-20".  This forecast would make this a top 5 March snowstorm for Boston, Worcester, Providence, and Hartford and certainly a 1-day record.

There are also coastal flood threats throughout the Northeast.  There was a full moon yesterday so tides are still running high.  A 2-3' storm surge will accompany Stella so minor to moderate coastal flooding is likely in the usually prone areas (Hull, Scituate, Brant Rock etc).  See the National Weather Service for more on this hazard.

I plan on starting a live blog tomorrow, so follow along here and post questions, comments, and photos to ZG Weather.  That will be fun as long as the power is on!!  There are a ton of hazards with this storm so please stay off the roads tomorrow and be ready for power outages.

-Zack Green