12:25AM
OVERNIGHT: Mostly cloudy. Patchy fog. Isolated showers and possibly a thunderstorm. Low 60-65. Wind SE under 10 MPH becoming S.
TUESDAY: Partly cloudy. Patchy fog and a chance of a shower before 7AM. Thunderstorms possible between 4PM & 8PM from west northwest to east southeast. High 80-85. Wind S 5-15 MPH becoming SW.
TUESDAY NIGHT: Partly cloudy. Low 60-65. Wind W 5-15 MPH.
WEDNESDAY: Mostly sunny. High 80-85. Wind WNW 5-15 MPH.
THURSDAY: Variably cloudy. Late shower possible. Low 64. High 84.
FRIDAY: Partly sunny. Chance of thunderstorms in the afternoon. Low 68. High 89.
SATURDAY: Mostly sunny. Low 66. High 91.
SUNDAY: Mostly sunny. Low 67. High 88.
Good Morning everyone! It looks like a day to keep an eye to the sky for the POTENTIAL of thunderstorm development this afternoon. The storm prediction center has parts of SNE in the slight risk area for severe weather today. The main threats look to be strong winds, vivid lightning, and downpours with any storms that do develop.
Thunderstorm Index at a 2 which is MODERATE since there is a threat for some severe weather. Don’t cancel any plans but be prepared if skies look threatening head indoors.
I still love Wednesday as it looks like a top 10 summer day!
Just read the latest discussion from the Storm Prediction Center and it looks like a severe thunderstorm watch will be posted for parts of SNE.
Great Job JJ!
Keep up the good work!
Thanks!
Severe Thunderstorm Watch just issued for far western parts of SNE until 7pm. There are already some severe thunderstorm warnings in upstate NY. It will be interesting to see if another severe thunderstorm watch box is issued further east especially if these storms could maintain their strength as they head for SNE.
Thank you JimmyJames!!!
We saw a brief break in the clouds this morning but it has been overcast all day. Would that tend to mean the storms will weaken as they move east? At least in the Framingham area?
Jimmy, I would be very surprised if eastern sections of SNE get any severe thunderstorms with all the cloudiness we have had most of the morning. The sun came out for about an hour earlier today but hasn’t returned since. In fact, David Brown on his nooncast hinted that most of eastern MA should be spared of any severe weather…just rain showers. Here in Boston, there is an ocean breeze and not too humid with dp’s in the low 60’s and very cloudy to say the least. I for one, am just not “feeling it” so to speak.
Continue to keep us posted as always Jimmy! Western sections are still very much under the gun for severe storms…bright sunshine in those areas. 🙂
Thanks, JimmyJames – after seeing some breaks of bright sunshine in Sudbury, even as I am writing now, I wouldn’t be surprised to see a few strong storms get into Central and even Eastern MA. Perhaps closer to the coast the storms might weaken.
Right now the storms are looking impressive in NY. It will be interesting to see if/how they evolve if/when they get here. I am hoping we don’t get any severe weather – maybe just some brief rain to water the gardens but not enough to ruin any outdoor activities.
I’m showing a West wind here in JP, so if there is an ocean breeze it must be
on the immediate coast. Still cloudy, 75 here. There may be enough dynamics
for the lift without sunshine. I’d wager a STW will be issued, even into eastern
sections. We shall see.
Some sunshine poking through…
Latest discussions from the Storm Prediction Center is talking about the possibilty a new severe thunderstorm watch box east of the current one
Latest from NWS @ 1:57PM
ENERGY SHOULD MOVE IN CONCERT WITH THE STRONG H5
CLOSED LOW AND ATTENDANT SHRTWV VORT MAX AS SEEN PER WV IMAGERY.
FORCED ASCENT…WITH AFOREMENTIONED SHEAR AND CAPE PARAMETERS…
AND FRONTOGENETICAL FORCING SHOULD KEEP THIS LINE FAIRLY ALIVE
THRU MUCH OF THE FCST RGN TOWARDS DUSK. STORMS SHOULD BE STRONG TO
SEVERE THRU THE INTERIOR…BUT FEEL CONVECTIVE CHCS WILL DIMINISH
AS THE LINE INCHES CLOSER TO SHORE AND BEGINS TO INGEST MORE
MARITIME BOUNDARY LAYER AIR.
Which mariteim boundary layer? Wind is not East. At\re they talking about from the South? Makes no sense to me.
Something I found. Hope some find interesting:
METEOROLOGIST JEFF HABY
The following are the main ingredients for supercell thunderstorms. The more ingredients available, the more spectacular the storm will be once it is taken out of the oven.
(1) Instability- Defined by the temperature stratification of the atmosphere. Instability increases by warming the low levels (PBL) and/or cooling the mid and upper levels (700 to 300 mb). It is most easily assessed by looking at thermodynamic parameters. The most important include the CAPE, LI, cap, and dewpoint depression between 700 and 500 mb. Dry air in the mid-levels combined with warm and moist air in the PBL will produce convective instability.
(2) Moisture (high dewpoints)- The more moisture available, the more latent heat that can be released once storms develop. It is important to look for moisture advection hour by hour on a day severe weather is possible. The air is more unstable in regions of dewpoint maxima. Here is a guide to dewpoint values and the instability and latent heat they can provide:
Greater than 75 Incredibly juicy
65-74 Juicy
55-64 Semi-juicy
Less than 55 Low moisture content
(3) Warm PBL temperatures- Air density decreases with increasing temperature. The greater the heating is during the day, the greater the instability of the atmosphere. Days with sunshine will be more convectively unstable than days with continuous cloud cover. The breaking of clouds on a day when severe weather has been forecast will increase the likelihood of severe weather. A temperature guide for buoyancy follows below (lift will determine if bouyancy is allowed to occur):
100+ Incredibly buoyant (if dewpoint greater than 55)
90-99+ Extremely buoyant (if dewpoint greater than 55)
80-89+ Very buoyant (if dewpoint greater than 55)
70-79 Fairly unstable (if dewpoint greater than 55)
60-69 Marginal (if dewpoint greater than 55)
Less than 60 Positive temperature and dewpoint advection needed
(4) Low level jet/ inflow- Strong low level winds will quickly advect warm and moist air into a region if it is associated with the low level jet. Unimpressive temperatures and dewpoints can change rapidly during the day via the low level jet. If winds are light in the PBL, severe weather is not as likely. Here are some low level jet wind values at 850 to keep in mind when analyzing:
Greater than 70 knots Incredibly fast advection
50 to 69 knots Very strong low level jet
30 to 49 knots Descent low level jet
20 to 29 knots Marginal low level jet
Less than 20 knots Ill-defined low level jet
(5) Strong surface to 700 millibar directional shear- Change in direction with height will cause horizontal vorticity which can lead to tornadic development. It also produces differential advection. Best case would be to have southeast wind at the surface transporting warm and moist air, a southwest or west wind at 700 millibar transporting dry air, and a northwesterly wind in the upper levels of the atmosphere.
(6) Strong speed shear with height- This will cause updrafts to tilt in the vertical thus leading to supercell storms. Speed shear also causes tubes of horizontal vorticity, which can be ingested into thunderstorms.
(7) Upper level Jet Stream- Use forecast models to determine the strength of the jet stream. The stronger the jet, the stronger the upper level forcing. Below is a guide to jet stream wind and upper level divergence (occurs in right rear and left front quadrant of a jet streak).
Greater than 200 knots Incredible divergence
150 to 200 knots Large divergence
100 to 149 knots Good divergence
70 to 99 knots Marginal divergence
Less than 70 knots Small divergence
(8) 500 millibar vorticity- Vorticity is a function of trough curvature, earth vorticity, and speed gradients. When using models to assess strength of vorticity you will notice a value is given for the VORT MAX. The higher the value, the higher the potential upper level divergence. Below is a guide to 500 millibar vorticity and upper level divergence. If the values of vorticity are being rapidly advected, divergence will “in the real world” be much more than if the winds through the vorticity maximum are stationary or moving slowly.
40+ Incredible divergence
30+ Very large divergence
20-29 Large divergence
Teens Descent divergence
Less than 12 Low but positive divergence
A lot to digest to say the least, LOL. 🙂
Sunshine getting more prevelant here in Boston since just after 1:00 pm. Radar more impressive west of Albany NY, but no storms yet in SNE. Still ocean breeze at Logan as of 2:00 pm. We may have to wait at least a couple more hours to determine if eastern sects are likely for severe storms as well.
Fwiw, I have noticed that so far this summer, storms become severe to the west, then fizzle quickly once reach east, then fire up again SE MA/Cape…let’s see what happens this time. The only exception was of course back on June 1st when sunshine was widespread early on in the day.
I’m about 5-6 miles from Logan. Light west wind here. 78 and as you say much sunshine.
We shall see.
Severe Thunderstorm Watch up for most of SNE effective 2:30PM
That watch goes until 10:00pm tonight.
Once we get past today a top 10 summer day on tap for tomorrow.
Sun has been out in Framingham since around 1:00ish also. Old Salty thanks for that post. I’ll have to read it a few times. It’s very interesting.
Limited sun through early afternoon over far eastern MA and a predominant wind direction SE to S, even at 2PM. Also, surface temps 78 or lower at all eastern MA locations, dewpoints in the 60s. Not alot of time to heat up, not alot of potential to heat up, and not alot of high dewpoint to advect in ahead of the line. If the upper dynamics are not strong enough to overtake all the negative factors in the Boston area, there’s about a zero chance of severe storms getting anywhere inside 495 and certainly inside 128. But we’ve been surprised before, so it’s not a situation to let our guard down, and we would not be under a severe tstm watch this close to the coast for no reason. I feel that the best action this go-around will be well west and southwest of Boston. But I’ll keep an eye on things, as I’m sure JJ will be doing. I’ll be on the road during the 5PM hour, otherwise here through the early evening hours.
The cell NW of Pittsfield MA at 3PM is taking on super cell characteristics.
I’m almost convinced that the heaviest stuff is now going to take place in west central, southwestern, south central MA, and parts of CT & RI. Come on Mother Nature, prove me wrong!
Springfield MA or its nearby suburbs get whacked by a storm during the 4PM hour. Severe weather possible there.
Some of the cells look to be gaining strength as this front moves across and it seems to be moving southeast and may go under a good portion of metrowest if it holds together. Of course since I don’t know a whole lot about all of this I may well be reading it incorrectly. Sun is still out with clear blue sky in Framingham. We have an occasional white cloud but it’s been out now for nearly 3 hours.
Don’t think that stuff reaches MetroWest as it is. Something new would have to develop on an outflow boundary ahead of and northeast of the main part of that line. Right now it looks like weakening elevated convection moves through all of the Boston area between 5PM and 7PM with more bark than bite. That’s usually good for some light to moderate pockets of rain but also the possibility of some cloud to cloud or cloud to ground positive lightning strikes. We’ll see how it plays out.
We will have to watch the other line currently in Upstate NY as that piece of energy would be the one that could send storms into the Boston area this evening if it holds together.
TK – what do you mean by “positive” lightning. Isn’t all lightning positive. I found that term interesting.
The short answer (I hope): Negative cloud to ground lightning is connecting a negative charge near the storm’s base with a positive charge near the ground. Positive cloud to ground lightning is connecting a positive charge near the top of the storm (often in the anvil region) with a negative charge on the ground some distance from the main storm (can be up to 10 miles away from the storm’s core, or even further). Positive lightning accounts for approximately 10% of cloud-to-ground lightning strikes, and is often much stronger than its negative cousin, due to the distance between + and – charges and build-up before discharge.
Much of the positive CG lightning occurs north of a squall line in the area of rain that is occurring in middle and higher clouds, and in some cases these bolts can shoot way out away from the storm (in any direction), but often behind the storm after it has passed by. The cloud-to-cloud versions of positive bolts result in those very long-lasting rumbles that often occur after a storm has gone by.
Thank you for that great explanation TK – I had never heard of positive or negative lightning.
Vicki – I agree with you. Looking at the radar, at this point anyway, it seems some storms are gaining strength and moving more southeasterly. But things in the weather department change constantly – I have seen storms weaken as they move towards MetroWest then pick up strength. Likewise – I have seen storms weaken as they move through Worcester and intensify as they approach the coast. This is what makes the weather so fascinating.
If things continue on the current course, TK could be right.
Sun is bright in Sudbury with scattered puffy white clouds on a bright blue sky.
Hi rainshine – the clouds look as if they are building over your way and getting denser.
Hi Vicki – you are right. They are building and there are more of them. Still some blue sky.
Just saw Matt Noyes and it looks like the heaviest storms at this point are to the southwest, ‘though there are still some storms to the north.
A severe storm that crossed Laconia NH about an hour ago (around 3PM) has encountered the marine-stabilized air over eastern NH and has fallen apart in a very short period of time. Same type of stability is in place in Metro Boston for now. That may leave us during the evening before the second area of storms (see above).
I hope what happened to the storm in Laconia (falling apart as it moved east into the cooler marine layer) happens to these storms in western Mass. We’ll be keeping our eye to the northwestern sky across the lake. Sunny now with temps slowly moderating through the 70s, a bit muggy and a nice breeze off of Buzzards Bay just to our south.
A tornado warning has just been issued just northeast of Springfield.
That thing just intensified really fast. My friend out there was sending pics via cell phone.
Springfield cell looks tornadic!
Now the cell is becoming lined-out and rapidly losing its identity. Should cancel the warning shortly if they have not already.
A sky warn spotter reporting a funnel cloud near monson. Wasn’t sure if it Touched ground. There was a second that didn’t touch ground
Getting dark in Sudbury and thundering.
3 major stations have been talking non-stop since 5 pm about the storm. Looks like storm travelling south into CT and RI.
Thunder intense in Framingham but I don’t see a cell on radar. Odd
Big flash of lightning here and big crash of thunder a few mins. ago. I think you can have thunder and lightning with just a lot of green in the radar. There looks to be some yellow – near Maynard and Worcester indicating heavier rain.
What is odd is that we are getting little if any rain right now and the radar is showing a dark green.
Which radar display were you using? I find the loop of the NWS’s radar tends to overdo precipitation.
And your lightning/thunder was very likely a positive discharge (see earlier posts).
Hi, TK – I was watching the Weather Channel doppler radar on tv – the channel that has continuous radars and info. w/o people.
And I found your post on positive/negative discharges regarding lightning very interesting.
I guess that is the NWS radar – and that is interesting – that their radar can overdo precipitation. Now that you mention it – I have noticed that when there is light green – it’s not even sprinkling out! Oh, well. Hope we are done with any severe weather for the night.
I was using the mycast app for iPhone. It didn’t shoe the precipitation but also didn’t seem to indicate the amount of thunder and lightning we were getting. Fascinating that it was positive. I was telling everyone here about your explanation
Heavy downpours and vivid lightning, there is flash flooding on rt 1 Wrentham
There’s a foot of water on road
Wow extremely bad down here, cars r broken down a few miles south of gillette, a ton of water
Wow Charlie. Incredible.
Steady rain now but moderate. Has never been heavy here either rainshine
Moderate rain here now.
I am wondering if there is the possibility of any more severe storms later – will they be as strong?
Severe Thunderstorm Watch now includes all of SNE except Cape Cod & Islands!
No rain yet here in Boston, but quite dark now. Occasional crackling noise on AM radio.
Philip the AM radio crackle brought back memories from my younger days when I’d hear the crackle and run to the window in anticipation. 🙂
Do you know that at night if you tune your AM radio to where there is no station you can hear static from lightning up to and even over 1000 miles away? It works best in the winter. The best example is one clear frigid night I was out driving, scanning the AM band one click at a time, and came across very obvious lightning static at the top of the band (near 1700 on the digital display). You can tell the difference between lightning static and interference from other sources. The nearest storms were in the Gulf Coast area as a winter storm was developing down there!
TK I know I’m pathetic but I got goosebumps reading yout post. That’s incredible.
You’re not pathetic. You’re just in touch with wonders of the world around us. We all share that in common to some degree.
I wonder if all who enjoy the weather events share that. Thanks TK
Thanks for all the reports everyone!!!
Storms have behaved pretty much as outlined above. Here in Woburn I am seeing an end of rain that lasted about 40 minutes from the elevated convection area north and northeast of the big storms. Only a few distant thunder rumbles as the stuff approached. Partial clearing coming in now and the sun’s about to come out.
Not completely out of the woods though… Have to watch that batch of storms in VT for about 2 1/2 more hours as it moves ESE.
Holy sunset, Batman!
We dodged the storm here in pembroke. Dark sky and thunder but not that much rain. I guess mother nature decided to spare us after Saturday’s hit. Going to work this morning up rt3 It was pouring.