Tuesday, May 31, 2016

Five Years Later- The Springfield, MA Tornado

Five years ago today a strong and borderline violent tornado tore through Western Massachusetts.  It was the strongest and deadliest storm to hit MA since 1995.  Portions of downtown Springfield were in ruins as were several towns further east.  Three people died and nearly 300 were injured.  The tornado caused around $160 million in damages.

Synoptic Set Up
WPC Surface Analysis 8 AM June 1, 2011 
A superb severe weather set up was present by 8 AM on June 1, 2011.  A strong surface cyclone in Ontario sent a warm front into surging into Northern New England.  In its wake a surge of warm tropical air with dew points into the 70's.   Meanwhile in the wake of the cyclone very dry air was dropping into the Midwest.    Surface winds were out of the south but at 14-18K ft they were more westerly creating strong wind shear.
NWS SPC reanalysis June 1, 2011 8 AM 500 mb heights, obs, temps

The Storm Prediction Center recognized the threat and had most of New England in a severe weather risk area.
SPC Day 1 outlook issued 2 AM June 1, 2011
Already by 9 AM an initial wave of severe thunderstorms erupted in South Central/Eastern MA & N RI.  I remember working outside and running for cover as these storms moved into the Blackstone Valley.  These were among the strongest thunderstorms I had ever witnessed and it was early in the morning.  I knew then that the atmosphere was primed for severe weather.  A rather severe squall line ripped through the Merrimack Valley.
GIS Radar Data Map  NEXRAD data June 1, 2011 840 AM (image NOAA)
Early Afternoon Developments
By 12-1 PM temperatures soared into the low 90's with dew points around 70.  Being in New England this is very rare.  The cold front was on the move and already in Central PA/NY
WPC Surface Analysis 2 PM June 1, 2011
The Storm Prediction center took note of these conditions at 1230 PM and issued this discussion
SPC Mesodiscussion
Broyes text for mcd 1048
This is as ominous as it gets for Southern New England.  Given a few false alarms over the past few years involving tornado threats I was somewhat skeptical.  I had seen all the ingredients for a severe weather outbreak seemingly come together without as much as a tornado warning.  So I went to Twin River right as the Storm Prediction Center issued a tornado watch at 2 PM
Tornado Watch 411 June 1, 2011 
The Tornado
SPC MCD June 1, 2011 415 PM

The best guess indicated the tornado touched down in Westfield, MA around 413 PM and continued into West Springfield at 417 PM.  As it entered Springfield the storm rapidly strengthened.  TV cameras in Springfield captured amazing video of the tornado crossing the Connecticut River and I-91 around 435 PM

Here is what the storm looked like on radar at this time.
NWS Boston radar reflectivity and velocity 5 PM June 1, 2011 (Joe DellaCarpini, NWS Boston)
The damage in Springfield was severe in the downtown area.  Parts of Springfield College were destroyed.  See photos of damage here.  There was no quit in the tornado as it moved into Southwest Worcester County after destroying many structures in Monson and flattening the Route 20 campground in Brimfield, MA.  The tornado reached its maximum width with moving through these communities.  The tornado damaged homes and structures in Sturbridge and Southbridge, MA before lifting off the ground near Webster/Oxford, MA.  The severe thunderstorm continued down Route 20 into Southern Worcester County.  I would say the Blackstone Valley should be grateful this storm ran out of energy when it did.
NWS Boston photos of 2011 tornado
June 1, 2011 will not go down as an all time US tornado like the April 27 storms or the Joplin storm of the same year.  However it is a reminder that Southern New England can and does get destructive tornadoes.  Next week I will review Massachusetts greatest tornado which happened to take place in Worcester.   The lightning show that night was something special as thunderstorms continued after sunset despite the loss of the sun.  Many people stayed in to watch the Bruins battle the Canucks in Game 1 of the Stanley Cup Final.  Meteorologists learned a lot that day that we will use to be prepared for the next June 1, 2011 type event.

-Zack Green

Quiet Weather This Week

Mostly dry and seasonable conditions are in store for Southern New England this week.  Memorial Day is traditionally the unofficial start of summer.  June 1 is the start of meteorological summer.  Temperature will not be as warm this week as they were the end of last week but they will be in the mid 70's.  Once again the coastal areas will be cooler than the interior. 

Short Term
A stalled boundary across SE MA and RI is dividing line between dew points in the 50's and dew points in the 60's
WPC Northeast Surface Analysis 11 AM
Temperatures everywhere are in the low 80's
RTMA 2 M max temps Monday 1 PM (image Weatherbell)
That second cold front along the Great Lakes and into Quebec/Ontario will move through overnight and it will be dry.  Temperatures drop into the 50's.  

A cooler air mass accompanies the cold front tonight.  Winds will also shift to the east keeping temperatures in the 60's near the coast, 70's in Metrowest/Central MA and low 80's in the Connecticut River Valley.
NWS NDFD Max temps Wednesday (image Weatherbell)
High pressure in the Canadian Maritime will be responsible for the easterly flow over the next few days as a cold front slowly moves east.  Here is the surface chart Thursday AM
WPC Surface Forecast Thursday 8 AM
This will keep temperatures down in the eastern part of the state again Thursday.  In Central and Western MA highs will remain in the low to mid 70's.  No precipitation through this period.

Approaching cold front will introduce afternoon showers/thunderstorms on Friday
WPC Friday AM surface forecast
High temps will linger in the low 70's.  More on the weekend forecast tomorrow.  Tomorrow is also the first day of the Atlantic Hurricane season (although 2 storms have already formed).

-Zack Green 

Friday, May 27, 2016

Second Look- Memorial Day Weekend

I get the feeling a lot of people called out of work today judging by the boat traffic on Webster Lake.  If you didn't don't worry the long weekend looks warm and mostly dry through Sunday evening.  There will be isolated showers and thunderstorms each day but these will last only an hour or two.  Guidance has continually over-forecast showers/thunderstorms each day this week so let's hope that continues.   Monday is a different story.  I am fearing a wash out.
Webster Lake, Webster, MA

Short Term Outlook
Showers and thunderstorms are popping up in the Northeast including Southern New England.  These are quickly raining themselves out.  There isn't much to move these showers so they could sit for awhile. A few stronger storms exist in upstate New York
NWS Northeast Regional Radar 
Taking a closer look at Southern New England
RadarScope Pro Boston radar loop
This will continue this evening.  The visible satellite shows less clouds today across SNE
GOES Visble satellite Northeast sector
Now looking at the temperatures the coast continues to suffer from the sea breeze.  It is much warmer inland.  Logan Airport currently reads 65 while it is in the mid to upper 80's outside of I-95.
RTMA 2 m temps 3 PM (image Weatherbell)
A bit early in the season for a day like this.  This is more like a 4th of July day but I will take it.  On Valentine's Day it dropped to -13 in Worcester . Perspective.  So if Worcester gets to 87 tomorrow (and they should) they will be 100 degrees warmer than Valentine's Day.  Most weather stations will read 90 tomorrow except for the Cape/Island and South Coast.
NWS NDFD max temp forecast Saturday (image Weatehrbell)
Why so warm?  A subtropical area of high pressure known as the Bermuda high is in perfect position to send southern air our way.  A front is hung up in the Midwest producing severe weather while we get a early taste of summer.
WPC Surface Forecast Saturday 2 PM
With this air mass some showers/thunderstorms will pop up.  My best guess for storms is South of the Mass Pike and west of 395 before 8 PM and then maybe into the Blackstone Valley around 9-10 PM.

The cold front in Northern New England will try to creep south on Sunday.  It will make some progress but ultimately it will fail and get hung up in Southern NH.
WPC Surface Forecast Sunday 8 AM

Coastal Southern New England will be much cooler than the rest of the region but outside 495 and even perhaps 95 temperatures will be in the mid 80's to 90 in the Springfield/Hartford region
NWS NDFD max temps Sunday (Image Weatherbell)
I am optimistic precipitation stays to north and west during the day Sunday.  Sunday evening into the overnight hours precipitation will begin to fall.

Tricky.  A Tropical Depression has formed in the Southwest Atlantic.  It will track towards the Carolina's and make landfall as a weak Tropical Storm named Bonnie.  Whatever is left of this will likely pump moisture up the coast overnight Sunday into Monday morning.  At the same time a cold front will be approaching from the west.
WPC Surface Forecast Monday 8 AM
 Here is one computer model simulation for 11 AM Monday
18z NAM simulated radar 11 am Monday (Image Tropical Tidbits)
Given that this rain will have roots in the tropics temperatures Monday won't be all that bad.  Most people are in the mid to upper 70's.   Let's hope this can clear out early enough in the afternoon so we can enjoy the day.  Honestly that doesn't seem likely but who knows.  The weather does what it wants.  I'll keep an eye on the radar but I'll watching Monday closely.

Have a safe and Happy Memorial Day weekend.

-Zack Green

Thursday, May 26, 2016

Thursday May 26, 2016 Weather Briefing

I've talked about the Memorial Day weekend several times already so I won't beat a dead horse.  I will update it tomorrow but I like my forecast.  I remain concerned about where exactly rain will set up on Sunday afternoon.  My advice to anyone who lives in Worcester County to the the coast to have a back up plan in case it rains.  This includes Rhode Island.  For more info on the week please watch the video below or see this post.

Short Term Outlook
Some cumulus clouds have developed in Central and Western New England
GOES Northeast visible satellite (image College of Dupage)
As of 4 PM a few sprinkles were present in Southern New England but no organized showers or storms.
NWS Northeast Regional Radar 
Guidance suggests some showers/thunder may move across Vermont and New Hampshire this evening.  Some of this activity could reach northern Worcester County.  I think we are good south of the Pike.  Now so far temperatures have behaved exactly as I expected for everywhere but Boston.  Winds are out of the east still and the temperature as of 4 PM is 69.  ZG Weather is a family friendly blog (most of the time) but I have some choice words for the east wind.  Here is the northeast temps as of 3 PM
Northeast RTMA 2 m temps 3 PM (image Weatherbell)
Temperatures tonight only fall to the low 60's.  Similar weather tomorrow.  I'll get to my Saturday/Sunday/Monday update tomorrow.  There is some interesting weather elsewhere in the States that I want to touch on.

National Outlook
Tornadoes have ripped across the Plains the last 4 days.  Here is one photo from Kansas yesterday from storm chaser Ian Livingston
Ian Livingston tweet May 25, 2016 Kansas tornado
Another incredible video can be found here.  This is from Reed Timmer who you may know from his Discovery Channel show.  Now with all severe weather there is some damage and causalities.  However several cities and towns have dodged major bullets as strong tornadoes have passed just outside populated areas.  Today is another chance for severe storms and tornadoes in the Central US.  All of the red boxes are tornado watches.  The blue is a severe thunderstorm watch.
SPC Convective Watches 420 PM EST 5-26-2016
 Let's hope these tornadoes stay away from populated areas again today.  Even though this is tornado alley 4-5 straight days is a little ridiculous.  But a deep trough in the Rockies combining with a eastern ridge is creating unstable conditions.  The flow into the plains is warm and tropical while the Canadian air dropping into the west is cool and dry.  Toss in a wind change with height and we have a good severe weather set up.
18z NAM 500 mb vort 8 PM Thur (image NCEP)
The moisture shows up well on this chart which is precipitable water.  Values over 1" stretch into Kansas and Nebraska
19z HRRR Precipitable Water 5 PM (Image Weatherbell)
Finally the area of low pressure off near the Bahama's is slowly becoming better organized.  I would bet this storm becomes either Tropical Storm or Subtropical Storm Bonnie this weekend.  Here is the NHC outlook for the next 5 days
NHC Atlantic tropical cyclone formation outlook
  The NHC is giving this a 60% chance of formation within 48 hours and a 70% chance within 5 days.  We aren't looking at a hurricane or anything like that but increased surf on a warm holiday weekend with periods of rain will certainly make an impact.  The low still looks like crap right now
GOES Visible Satellite over 91 L (image NOAA)
Conditions should become more favorable by Saturday.  The Air Force will investigate the system tomorrow afternoon.   Come Tuesday-Wednesday, whatever this system is, may help enhance precipitation in Southern New England.  

Now that I have crashed your browser with all these graphics and GIFs I'll leave it here.  As I said above one more forecast tomorrow for the weekend.  I'll be tracking any potential thunderstorms over the weekend but you know...its a holiday weekend.

-Zack Green

Wednesday, May 25, 2016

First Look- Memorial Day Weekend

The unofficial start of summer is Memorial Day weekend and for once Mother Nature agrees.  Although temperatures will back off from the mid to upper 80's on for Sunday/Monday it will still be warm.  There will be isolated afternoon showers/thunderstorms on Friday but I am hopeful that most of the action on Saturday is to our west.  On Sunday a front from our east will touch off isolated showers before moving back east on Monday.

General Overview
High pressure is now in control as yesterday's low pressure system departs.
WPC Surfae Analysis 8 AM
Our wind direction hasn't completely flipped to the west yet so temperatures are in the low 70's in some places.  But even I was write this and look at the local weather station network I notice a lot of stations are rising rapidly.  Local high resolution guidance is forecasting upper 80's for most this afternoon.  Look how awesome it captures the sea breeze effect.
14z HRRR 2 m max temps 4 PM (image Weatherbell)
So why does the sea breeze have such a profound effect on the coast?  The answer lies in the ocean temperatures.  They are still chilly from the Mid Atlantic on north.
NOAA/NCEP Sea Surface Temperatures (image Weatherbell)
*I will reference this map again in a bit but please notice the streaks of yellow off the Carolina coast*.  As for sea breezes the land heats up, warm air rises but cools with height.  It then sinks over the ocean and spreads out.  The ocean returns the favor by forcing the air back onto land.  This graphic will explain much better
NOAA COMET program Sea Breeze diagram
For those heading to the coast this weekend you are now warned that it will be much cooler at the coast than inland.

Low temperatures Thursday morning will be around 60 region wide.  A cold front will push south on Thursday.  This front will be fairly weak but it may set off a shower or thunderstorm later in the day.  Temperatures will be similar to today with highs in the mid to upper 80's.  Dew points will be higher tomorrow so it will feel more humid.  Here is the forecast surface chart tomorrow evening.
WPC Surface Forecast Thursday 8 PM
A greater chance of scattered showers/storms will be overnight Thursday into Friday.  This cold front will stall and lift north a warm front.  The precipitation wanes by daybreak and we will be left with a warm and sunny day.  Here is the Friday AM surface forecast.  I do want to watch and see if the shower activity holds on a bit longer Friday morning.
WPC Surface Forecast Friday 8 AM
Temperatures Friday will be in the mid 80's north and west of the Boston-Providence-Hartford line as some ocean air works into the coastal plain.  The usual warm spots- Connecticut River Valley, Merrimack Valley will be the warmest.  It will also be humid with dew points in the 60's.  Hopefully the southwest wind will be strong enough to keep everyone comfortable.
NWS NDFD max temp forecast Friday (Image Weatherbell)
Saturday is simply hot and humid.  I believe the day will be mostly dry in Southeastern New England but I can't rule out a shower/thunderstorm in Western MA.  This is Worcester, Boston and Providence's best day to hit 90.
NWS NDFD max temperature forecast Saturday (Image Weatherbell)
The forecast for Sunday is bit more tricky.  First of all before people get worried I am not forecasting a crappy day in fact it could be the pick of the weekend in some spots.  But a front may back in off the Atlantic and cool everyone off and bring some rain.  Here is the projected surface chart
WPC Surface Forecast Sunday 8 AM
The boundary will linger in the area Sunday and Monday.  If you are to the west or south of the boundary temperatures will be in the 80's.  If you are to the east or north of this temperatures could drop into the 60's.  Anytime there is that steep a temperature gradient there is a chance for showers/thunderstorms.  Monday the front weakens so odds favor a mild and sunny day.  I'm thinking temperatures around 80, cooler at the coast.

Now notice the area of low pressure sitting off the Georgia coast Sunday AM.  If you can recall the sea surface temperature graphic above you will remember this is sitting over warm water.  Hurricane season does not start until next Wednesday but it is possible a Tropical or Subtropical Storm forms off the Carolina coast.  This will have no bearing on the weekend forecast here in Southern New England but it may play a role in our weather next week.  There isn't much to move this system so it will sit and spin offshore.  It may enhance moisture in New England the middle/end of next week.  The National Hurricane Center gives the low a 50% chance of developing into a tropical/subtropical storm in the next 5 days.
NHC 5 day formation outlook
If this storm receives a name it will Bonnie.  Are you on the list this season?  Here are the names (Alex formed in January-very rare but counts to the 2016 season)
2016 Atlantic Hurricane Names
I will be posting a video later today going over my weekend forecast.  Enjoy the warm weather

-Zack Green

Tuesday, May 24, 2016

Rain with Isolated Thunder This AM

Some of you may have awoken to a few rumbles of thunder this AM (I know I did).  Bands of showers and thunderstorms are wrapping around a surface low south of New England.  The first band is lifting through the Blackstone Valley now (as of 445 AM).  This band extends to Boston and Springfield as well.  I expect another band around 8 AM.  Here is the radar loop this morning
NWS Northeast Regional Radar Loop
The counter clockwise motion of the low shows up nicely on radar.  Here is the zoomed in surface chart
WPC Northeast Surface Analysis 2 AM
Here is the radar as of 8 AM.  I feel this could be overdone in Eastern MA but keep the umbrella handy and give yourself an extra 15 minutes if you are commuting this morning.
07z HRRR Simulated Radar 8 AM (image College of Dupage Weather Center)
The rain shifts to Western MA and Northern CT this afternoon.  We should stay dry in Central and Eastern MA/RI.  Northeast winds keep temperatures around 60-65.  Winds begin to shift this afternoon and temperatures will rise overnight.

I have some changes to my weekend forecast that I will discuss in my next post.

-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...