Monday, November 19, 2018

Rain Ending As Snow For The Blackstone Valley Tuesday

Tomorrow is Tuesday and surprise, surprise...precipitation is in the forecast.  WBZ went back and found that there has been measurable precipitation on 9 of the last 11 Tuesdays.

For many north and west of 495, tomorrows precipitation comes in the form of snow.  While all rain is on the table in Rhode Island and Southeast Massachusetts, Southern Worcester County, Southeast Middlesex County, and Essex County will deal with mostly rain but there will be mixing at times before ending as a coating to 1-2" of snow.  We clear out Wednesday before historic cold invades for Thanksgiving.

A Winter Weather Advisory has been issued for Northern Worcester County, parts of Western MA, Southern VT, Southern NH, and Southern ME. 

NWS Monday PM Headlines
I would add Northwest Middlesex County to this and I would also add Northern Essex County to this and they may be added this evening or tomorrow AM.   There are no headlines for the Blackstone Valley and I don't anticipate any being issued, although untreated roads will get slippery tomorrow afternoon.

General Overview
Another wave of low pressure will track along the Southern New England coast, increasing in strength as it does so.  Snow begins to fly near the MA/NH/VT boarder just after midnight.  A few showers will be possible in the Blackstone Valley at this time but most of the precipitation holds off until 5-6 AM.  Even in the Valley, some precipitation may fall as sleet or freezing rain but the predominant p-type will be rain.    I will urge caution when traveling. 

WPC Surface Fronts/Precip Tuesday 7 AM. 1 PM, 7 PM

Temperatures will be in the low to mid 30's and will fall a bit during the day.  So as we get to the afternoon, the snow that will be falling north and west of  495/Pike will sag south and east.  This change happens in the Blackstone Valley late Tuesday AM. 

18z HRRR Simulated Radar Monday 8 PM to Tuesday 9 PM (image
Tuesday night we start to head towards Mid-Winter type temperatures as an Arctic air mass invites itself over for Thanksgiving dinner.  More on this tomorrow.

Timing and Impacts
From the Pike to Rt 2, I expect 2-4" of snow, including the city of Worcester.  3-6" amounts are likely in extreme Northern MA and into Southern VT, NH, and ME.  I also expect 2-4" around Lawrence, Haverhill, and Methuen.   Snow could briefly fall at rates of 1"/hr in these spots late morning and early afternoon.  I am only expecting a coating to 2" around and just south of the Pike.  This image is from the HRRR model and I think it is spot on.  (Note- Click to enlarge all photos.)

18z HRRR 36-hour Snowfall (image
It always amazes me how many people in New England have vehicles that do not perform well in the snow.  Its also early in the season so not everyone has their snow tires yet.  As a result, that coating to an inch in the Blackstone Valley can very easily screw up traffic.  The take home message is to give yourself some extra time for both commutes tomorrow.  It looks like it is going to be a long winter.

-Zack Green

Wednesday, November 14, 2018

Winter Storm Headlines Issued Ahead of Thursday-Friday Storm

The National Weather Service in Norton, MA has issued a *Winter Storm Watch* for interior Southern New England a *Winter Weather Advisory* for communities inside 495 and RI/S CT.

NWS Boston Headlines (CLICK TO ENLARGE)
The watch begins at 7 PM tomorrow evening and continues until 7 AM on Friday.  There is little doubt that precipitation begins as snow.  The snow will change to sleet and freezing rain and eventually plain rain.  The exact timing of this transition is still a bit of a wild card.  Many communities will also end as snow Friday morning/early Friday afternoon as the storm races into the Gulf of Maine.  The highest uncertainty is from Hartford to Worcester to Lowell where 6+" of snow is possible if it stays all snow.  Let's discuss.

General Overview
WPC Surface Fronts/Precipitation Thur 7 AM, 7 PM Fri 7 AM, 7 PM
The storm system will lift northeast tomorrow, spreading snow, sleet, freezing rain, and rain up the Eastern Seaboard.  Working in favor of snow is the cold air mass already in place across the Northeast.  Temperatures tomorrow will be in the upper 20's/low 30's.  By 7 PM temperatures will be back in the upper 20's.  That sets the stage for frozen precipitation to begin as the storm begins to reform near the Mid-Atlantic coast. 

18z NAM 3km Sim Radar/P-Type Thurs 7 PM (image Tropical Tidbits)

The majority of the snow falls during the 7 PM-midnight time frame.  Solutions diverge as the clock turns to Friday.  The EURO model makes this a Cinderella snow and keeps the fun going past midnight.  The American NAM turns it into Sleet-fest 2018.   The NAM has trended a bit colder in its latest run.  Working in the NAM's favor is the calendar.  The "warm" sea surface temperatures mean any wind from the east will end the snow and cause a change over to sleet and then plain rain.  A storm track along Long Island and over the Cape would also favor a change over to sleet and then rain or drizzle.

This is the EURO at 11 PM tomorrow night.

12z EURO P-Type/Mean Sea Level Pressure Thurs 11 PM (image
The NAM at the same time.
18z NAM 3km P-Type (image

What is causing these differences?  Subtle differences in the temperature profile, which is not uncommon at this time range.  The calendar and the track of the low certainly favors a change to sleet and rain.  Despite that, the temperature profile does support heavy snow especially with heavy precipitation.  So where does that leave us?

If you are traveling home from Hartford or Providence, leave a bit early as the beginning of the snow will fall at the end of the evening rush.  The commute from Boston and Worcester should be fine.

The initial burst of snow will drop 2-4" of snow, with rates near 1"/hr between 9 PM-12 AM.  As the upper levels warm, snow changes to sleet and then freezing rain or drizzle.  It will be tough to dislodge the cold so this will likely continue until sunrise.  This happens first in RI and Eastern Massachusetts, especially inside 95/128.  Then it will work towards 495, the Pike, and Rt 2.  An extra hour or two of snow means an extra inch or two of snow.    As the precipitation intensity decreases, the snow/sleet will turn to drizzle or freezing drizzle.  This really is a mess!  

Allow of extra time Friday morning because the commute will be slow, especially those coming from Central and Northeast MA.    For school administrators and public works departments, my advice is to plan for 4-7" of snow as well as 2-3" of snow followed by sleet and freezing rain.  Here are the NWS totals for both snow and ice.

NWS Snow/Ice Forecast (CLICK TO ENLARGE)
As the storm departs late Friday morning/early Friday afternoon expect one final round of rain south of the Pike and snow north of it.  Winds increase behind the storm and cold air returns for the weekend.    I will be at a conference tomorrow but I will get an update on the blog one way or another.

-Zack Green

Tuesday, November 13, 2018

Stormy Pattern Continues, First Snow Likely For Many Thursday Night

When I look into your eyes

I can see a love restrained
But darlin' when I hold you
Don't you know I feel the same
Nothin' lasts forever

And we both know hearts can change
And it's hard to hold a candle
In the cold November rain

(If you now have Guns N' Roses in your head and have 10 minutes to kill, you can find the music video for November Rain here.)

Rain has been a constant theme so far this fall, continuing a pattern that declared itself in July.  Since July, Worcester is averaging 5.7" of precipitation per month!  That does not include the 4.94" that has fallen so far in November, which doesn't include today.  We have a 6" precipitation surplus over the past 5 months and that will only grow as November progresses.  Flooding has not yet been a major issue.  So far, the spacing between these rain events has been long enough to allow for the rivers to breathe.  Even with today's event, most predictions keep the Blackstone River in its banks over the next 7 days.  You can check on your local rivers here.

WSI Intellicast Northeast Regional Radar 930 AM

This storm system is helping to kick off what will be a banner week for Thanksgiving skiing in Northern New England.  The rain will end early this afternoon in Southern New England with clearing skies and a sharp temperature drop this evening.   Temperatures tonight will fall into the teens in NH, VT, and ME and into the mid 20's across MA, CT, and RI.   Max temperatures tomorrow will struggle to get into the mid 30's in Central and Western MA.  Temps will be in the upper 30's across CT, RI, and Eastern MA.

NDFD 2 m max temperatures Wednesday (image
Temperatures Wednesday night into Thursday morning will be in teens most places.  Even across the Cape and Islands temps should be in the mid 20's.

NDFD 2 m min temps Thursday AM (image
High pressure will be in control so mostly sunny skies will accompany the winter blast on Wednesday.  The high will begin to be pushed to the east by a developing storm system in the Southeast US.  By Thursday AM, a sprawling, messy system with lots of moisture will begin moving northeast.  High clouds will also arrive prior to the precipitation.  Thursday afternoon will feel and look a lot like winter.

WPC Surface Fronts and Precipitation Thursday 7 AM
 The Thursday evening commute should be just fine in Southern New England, although I will be watching the trends.   Temperatures Thursday will struggle to get out of the low 30's and will be dropping into the mid to upper 20's by Thursday evening.   The cold, dense air mass will tough to dislodge initially so everyone in Southern New England begins as snow.

12z NAM WRF Hi-Res Simulated Precipitation Type Thursday 7 PM (image

Some snow will change over to sleet and freezing rain as the storm tracks near Long Island and across the Cape and Islands.  The snow will quickly turn to plain rain across Eastern MA and Southern RI just after midnight.  Snow will hold on a bit longer in Worcester County before turning over to rain before 5 AM south of the Pike.  Snow turns to sleet, freezing rain, and then plain rain around 7 AM south of Route 2.  I'll have to watch the Merrimack Valley in case cold air holds on longer than currently modeled, as history tells us it may.   Rain will continue through the early afternoon, maybe ending as some snow/sleet/freezing rain before tapering off.

The Bottom Line

Snow begins after 7 PM on Thursday.  Accumulating snow falls from around midnight to 4 AM in Southern Worcester County.  Accumulations of 1-3" are likely.  A brief burst of sleet and freezing rain is possible between 4-6 AM before going over to all rain.  Although annoying, with a little bit of extra time everyone should be able to get where they need to go.  Consider this our "fall training" for winter.

-I will update tomorrow with the latest trends and timing and the all important snow accumulation map.

-Zack Green

Friday, July 27, 2018

The Blackstone Valley Dodged A Bullet

- The Blackstone Valley dodged a bullet with the twin 7/26 tornadoes.  They were bad enough and its almost a miracle that there are no injuries.

Pine Grove Cematary Whitinsville, MA (image Steve Falconer)

  • Nocturnal Tornado
    • The 230 AM arrival time meant most people were sleeping.  Nocturnal tornadoes account for only 27% of all tornadoes, but they are responsible for 39% of all tornado deaths. 
  • No Tornado Warning
    • The National Weather Service issued a Severe Thunderstorm Warning at 232 AM.  It arrived at 232 according to the NWS Public Information Statement about the tornadoes.  A Tornado Warning would likely have triggered the emergency alert feature on many cell phones.  There was no real warning.  
    • I don't blame the NWS.  They issued the Severe Thunderstorm Warning when the velocity scan reached the threshold for severe wind.  It was a unique small supercell as the SPC Mesoscale Discussion called it, but not until 3 AM.  This was on no one's radar.
    • MEMA claiming that there was warning is technically true, but they are fortunate there were no causalities.  A severe thunderstorm warning issued as the storm hit containing the language "a tornado is possible" isn't adequate warning for a nocturnal tornado.
  • Lack of Lightning 
    • The largely uncomfortable tropical air mass ensured air conditioning units would be running on high.  With no thunder to roar over the a/c's, residents woke up to trees slamming against their homes or crashing in the woods.  I saw a lot of people on social media saying that they did not even know there was a storm.
    • Tornado Track Avoided Densely Populated Areas
      • There is significant damage to dozens of residences.  If the storm had tracked in a route where the 4.4 miles took it from the Village to Rockdale in Northbridge, several hundred to even over a thousand families could have suffered structural damage to their homes or apartments.  An even worse track would be the second tornado then tracking down in Grafton or Millbury.  

    • Tornadoes sine 1950
      • Douglas- 1 (7/26/18 EF-1)
      • Uxbridge 1(7/26/18 EF-0)
      • Northbridge 2 (6/9/53 EF-3, 7/26/18 EF-0)
      • Upton 1 (7/26/18 EF-1)
    • Tropical Air Mass Continues
      • Tropical air thanks to south/southwest winds will continue Friday and Saturday.  Severe weather looks to stay in Western MA and Northern CT on Friday with damaging winds and flash flooding as primary hazards.  Storms will weaken as they approach the Blackstone Valley.  That said, high resolution guidance is holding these storms together in Rhode Island and Southeast MA through midnight, especially towards the coast.
    11z HRRR Simulated Radar Through Saturday 1 AM (image
    Additional storms may fire Friday as the triggering cold front will be slow to push offshore, largely thanks to stubborn Bermuda High.  Saturday afternoon humidity should decrease we the region gets a small break from the oppressive air.  

    Until next time.

    -Zack Green

    Thursday, July 26, 2018

    National Weather Service Confirms 2 Separate Tornadoes in the Blackstone Valley

    The National Weather Service in Norton has confirmed that two separate tornadoes touched down in the Blackstone Valley early this morning.  The twin twisters were each rated at EF-1 with winds of 100 MPH.  The first touched down in Douglas and tracked through Uxbridge and into Northbridge before lifting up around Lasell Field and Pine Grove Cemetery.  A second tornado touched down in West Upton around Main Street.

    Severe weather in Southern New England is just different than the rest of the country.  Rare is the big discrete supercell thunderstorm that is common in the Midwest and Southern US.  They do happen;  the 1953 outbreak that produced the infamous EF-4 Worcester tornado and the EF-3 Sutton-Northbridge-Mendon tornado (by my records the last tornado to track through Northbridge) were classic supercell thunderstorms.  This storm was anything but.  I didn't see a single flash of lightning.  But it is consistent with a few tornadoes that have hit Massachusetts in the past few years.  The Concord, MA twister of 2017 and the Revere tornado of 2014 immediately come to mind.
      But it really does sound like a train when a tornado moves through.  As I outlined in my last post, I was lucky enough to be thirsty for a drink of water around 2 AM last night.  I always envisioned my first tornado to be in the Midwest somewhere on a chase-vacation.  I missed one in 2013 in which friends and classmates of mine were able to see a tornado in Kansas (I think).  It was pitch black so I didn't see a classic tornado but I think I'm all set seeing one now that I can see what an EF-1 tornado can do.

    Here is the NWS write-up for tornado number 1.
    Here is tornado number 2.

    To all my new readers who joined today welcome.  I blog full time in the winter but only sporadically in spring, summer, and fall.  But when life-threatening weather hits I will also post.   Here are some pictures from Douglas, Uxbridge, and Northbridge (I covered Upton this morning before I realized what actually happened in my own backyard).

    Widespread Wind Damage in Upton After Wild Storm

    A small section of Upton, MA is recovering this morning after a severe thunderstorm brought severe damage to Main Street, Warren Street, and Ephraims Way around 240 AM.  National Weather Service survey teams will investigate to determine whether or not this damage has been caused by a tornado or a microburst.  Early indications are that this is a tornado, but the final assessment is to be done by the NWS.
    I woke up around 2 AM to get a drink of water and since I knew some intense weather was possible, I checked the radar.  What I found was a developing supercell thunderstorm with weak rotation heading directly towards Uxbridge, Northbridge, and Upton.

    Radarscope KBOX radar 220 AM
    The hook just south of Uxbridge in the top image and the hint of bright green next to the brighter red in the same spot in the bottom image instantly caught my attention.  This indicated rotation as the red and green colors measure the direction and velocity of upper level winds.  At this point the rotation is still weak.  However, any strengthening of the rotation could produce a weak tornado or a microburst.  Just 5 minutes later as the cell crossed into Uxbridge that is exactly what happened.
    I went out to my porch and around 235 AM there was a 30-45 second burst of intense rain and gusty winds, but no immediately obvious damage occurred in my section of Whitinsville .  Just after passing through my area the rotation tightened even more.  I was concerned about the Riverdale and Rockdale sections of Northbridge.  Meteorologists from Alabama and Oklahoma started to tweet me expressing concern over what they were seeing on the radar.

    This is all meteorological jargon so if you can't follow along that is OK, that is what we went to school for.   The point is, this was no ordinary severe thunderstorm for Massachusetts.  The National Weather Service did issue a Severe Thunderstorm Warning at 232 AM.  In the warning it says a tornado is possible, although no official tornado warning was issued.
    Shortly after the Storm Prediction Center in Norman, OK issued a "mesoscale discussion" noting the potential for isolated tornadoes. 

    Not long after I saw Upton PD tweet about numerous emergency calls around Glen Ave and Main Street.  I'm glad the damage is isolated, but it is significant for the folks who were hit.  There have been no reports of injuries thankfully.  I haven't been to bed (save for a 25 minute nap on the train) so I will be going to get a coffee.  I'll have more on this later after the NWS survey is complete.   

    -Zack Green

    Friday, June 1, 2018

    Back To My Roots

    June 1 is a significant day in meteorology both locally and across the Western Hemisphere.  It was 7 years ago today a devastating severe weather outbreak began in the morning hours in Central/Eastern MA/Northern RI and was capped by a high end EF-3 tornado that tore through Springfield and into Southwestern Worcester County.  I graduated from college just days prior with no job prospects in the field of meteorology (at the time I blamed the job market- in hindsight I should have done more with the opportunities that were available to me in college).  June 1, 2011 inspired me to start a blog which I did a week later right here at this exact address  I wasn't "in the field", but I was still actively practicing the science of meteorology.  I was looking to justify the money my parents and I spent on my education and this filled that role for me.

    I blogged off and on for 6 years covering events such as Hurricane Irene, the 2011 Halloween Snowstorm, Hurricane Sandy, the Blizzard of 2013, the Blizzard of 2015 (and that entire crazy winter), as well as the 2016 drought and countless other smaller weather events.   It led to a short lived role as a national blogger for a storm chasing company called Tornado Titans. By June 2017 page clicks were up and I decided to get bold and pull the trigger on something I have always wanted to try; my own meteorology website.  I purchased a domain name and attempted to sell premium weather content.  I moved the platform to WordPress and established Blackstone Valley Weather Service.  Page views quickly plummeted as I put content behind a paywall. And I get it.  Why pay for weather when there are so many places to get it for free?  

    Eventually I dropped the paywall and the page views returned in force this winter.  But I wasn't going to keep the domain.  I spent a lot of money trying to get the new page started but with no money coming back to me it is not sustainable.  On top of that I took a new job as a consultant in the environmental/engineering/atmospheric science world so I have event less time than I did before to commit to growing revenue.  The domain name is also too long.  Next time I launch a new site, and there will be a next time, the name will be short and to the point.   I learned a lot trying and ultimately, for now, failing to start a business.   The "business" side failed but the blog grew.  Facebook likes are approaching 800 people and page views in March were AWESOME.  

    So what is next?  For now I will return to my roots right here on Blogger.  I have missed blogging.  There is something that is therapeutic about talking about the weather.  As I look back at some of my past work, I'm proud of the effort I put in and look forward to delivering more quality work to my readers in the future.  Today is not only the anniversary of the 2011 New England Tornado outbreak but also marks the beginning of the North Atlantic Hurricane Season.   Although slightly odd for a New England meteorologist, I've always been enthralled by Hurricanes.  Today just feels like the right time to start blogging again.  

    Sara replaces Sandy on this list.  Sandy is just the 4th name from the original 1982 list to replaced.

    Gordon replaced Gilbert and Joyce replaced Joan after the 1988 season.  Kirk replaced Keith after the 2000 season.  In comparison, the 2023 list is full of retirements.  

    Being the list for the deadly 2005 and 2017 have allowed for this list to stray far from the original in 1981.  Past performance of the list has nothing to do with the upcoming season of course.  There is hope for a quiet season thanks to cooler than normal sea surface temperatures in the Main Development Region of the tropical Atlantic.  If this persists, it would help to limit tropical development between the Western African coast and the Caribbean islands.  After Irma and Maria, I certainly hope this is true.
    OSPO Global SSTA 5/31/18 (image NOAA)
    For comparison here is 6/1/17.  Notice the abundance of warmer than normal water between the islands and Africa.
    OSPO  Global SSTA 6/1/17 (image NOAA)
    Most forecasts are calling for an average season with 10-14 named storms, 5-8 hurricanes, and 1-3 major hurricanes.  We've already had one named storm, Alberto.  Alberto tracked northward from the Western Caribbean Sea into the Gulf of Mexico before making landfall along the Northern Gulf Coast on Monday.  The storm tracked into the Great Lakes.  The remnant energy is in Eastern Canada and is indirectly responsible for the humid weather today and tomorrow.

    A few showers will be possible this afternoon with dew points in the low 70's.  Saturday will be similar but a cold front will drop south late tomorrow afternoon/early evening.  Tomorrow is not a washout and should be dry for the majority of the afternoon.  Temperatures cool down on Sunday as the pattern changes to a cooler and potentially wetter regime.  

    Thanks for reading and welcome back.

    -Zack Green

    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...