Hot Weather May Lead to Severe Weather Today, Rough Surf at Coast

A strong cold front driven by a rather anomalous upper level low pressure system in Ontario will enable showers and thunderstorms to develop in the Northeast today.  Given high temperatures and dew points some of these storms will be severe with a primary threat of heavy rain and gusty winds.  Seasonable summer weather will follow Friday through the weekend.

General Overview/Short Term Forecast
This morning's surface analysis over the Northeast shows a stationary boundary over Maine and a cold front trailing through Ontario, Western NY and Western PA.

WPC Surface Analysis 5 am

One can see this on the 7 am temperature map.  In downeast Maine temperatures are running in the upper 50's.  For Southern New England the majority of us are well into the mid to upper 70's.

RTMA 2 m temperatures 7 am (image Weatherbell)

Some showers and thunderstorms have already developed in New York.  These may hold together as they approach the Hudson River and Western New England.  In fact some high resolution short range guidance believes this not only holds together but actually strengthens it around 3-4 PM for parts of Central MA, CT, and RI.

NWS Northeast Regional Radar loop 808 am

By 2 PM temperatures should be near or above 90 for most of Southern New England.  For some this will be the 3rd day in a row of 90 + temperatures and thus a heat wave.

11z HRRR 2 m temps valid 2 PM (image Weatherbell)

At 3 PM dew points are expected to be in the 70's.  Look at how comfortable the air is behind this front however.

11z 2 m dew point temperatures valid 3 PM (image Weatherbell)

This is an incredibly tropical air mass for Southern New England standards.  Of course just 6 months ago this is what the 8 am temperatures looked like.

January 31, 2015 8 am 2 m temps (image Weatherbell)

There was also 3 feet of snow on the ground and another blizzard about to impact the region so I'll take a few days of oppressive heat.  The amount of moisture available to any showers or thunderstorms that develop today is impressive.  It is the biggest threat with any storms although gusty winds (low chance of a downburst due to tropical nature of atmosphere) and a brief tornado is possible (unlikely, but still a chance).

 

11z HRRR Precipitable Water forecast 4 PM (image Weatherbell)

A secondary round of showers and storms is likely for Western New England later this afternoon.  I think these storms have the best chance to be severe.  I will be watching throughout the day.

Other Weather Headlines
It appears unlikely severe weather will hold together and reach SE MA.  However the main weather headline for the Cape and Islands, as well as all South facing beaches, is building surf and rip currents.  A small craft advisory is in effect for much of the MA/RI/CT shoreline and offshore waters.

In other news the tropical Atlantic hurricane season continues to be slow.  There are two areas that the National Hurricane Center is watching for possible development, but it gives each a 10% shot in the next 2 days, and only 30% in the next 5 of actually becoming a Tropical Depression/Storm.

NHC 8 am tropical weather outlook

In other good news the drought that had intensified in May is all but gone from New England.  It has been confined to the South Coast and Southern Maine.

Northeast US Drought Monitor (image USDM)

Today should put more of dent into these numbers but overall the next week looks mainly dry.  Seasonable temperatures and dry weather will make it one of the best vacation weeks of the year. 

Finally there will be a full moon tomorrow, the second of July.  That is somewhat rare and it is a called a Blue Moon.  There will not be another Blue Moon for 3 years.  Don't worry about that however.  One can always find Blue Moon at the local package store.  I prefer that type of Blue Moon over the astronomical one.

That's all I've got for now.  I'll talk to you if/when Severe Weather watches go up.

-Zack Green

Severe Thunderstorm Watch Issued for Parts of New England

The Storm Prediction Center in Norman, OK has issued a Severe Thunderstorm Watch until 11 PM for a significant portion of New England.

Severe Thunderstorm Watch until 11 PM (via SPC)

The primary threat will be damaging winds, although hail up to 1" in diameter and isolated tornadoes are possible.  The initial radar is rather quiet although there is a severe storm right now around Laconia, NH.

NWS Northeast regional radar (2 PM)

However as a weak impulse moves through the Hudson River Valley into New England

WPC 11 am surface analysis 

and into temperatures near 90, with dew points into the 70s more thunderstorms should develop,

rtma 2 m temperatures 2 PM (image weatherbell)

South of the Mass Pike should be ok through early evening.  Activity may organize into a convective complex after dark.  This complex would likely bring heavy rain and strong winds with it so keep tabs on the situation throughout the afternoon/evening.

If anything major happens I will update my post.

-Zack Green

Severe Threat Still Exists

Two rounds of severe weather are likely in Southern New England today.  It does appear as if the first round of thunderstorms will help to limit the potential for the second round.  We are still at risk for frequent lightning, damaging wind, large hail and torrential downpours.  The tornado threat is small, but not zero.  Still if we able to get the sun out all morning/early afternoon there would be a greater chance at a significant twister. 

GENERAL OVERVIEW
The regional radar shows two main areas of showers and thunderstorms.  One is moving through Northern New England, the other through NY, PA and heading towards SW New England.

NWS Northeast regional radar loop (908 am)

Short range guidance is indicating this holds together and impacts Southeastern New England by 12-1 PM.   A lot of the action right now is driven by a warm boundary driving northeast into the region.  Out ahead of this the sun is breaking out in Worcester County and even from time to time in Andover. 

GOES_East visible satellite image with surface analysis (NOAA)

The Storm Prediction Center has taken note of this and issued a Severe Thunderstorm Watch for most of Southern New England

SPC Severe Thunderstorm Watch 341 until 4 PM

This is mainly for round 1 of the thunder.  Looking at all the data, the visible satellite, and high resolution guidance I am beginning to believe this may cause the biggest headache for many.  The straight line wind damage potential for this is real, especially if it evolves as it enters the unstable atmosphere in Southern New England. We shall see what happens in the next few hours.  I will try an update later this PM. 

-Zack Green

Severe Weather Likely Tomorrow

Powerful thunderstorms have left a swath of damage across the Upper Midwest and Great Lakes today.  Tomorrow this system will slide east and bring the severe weather threat to New England.  Everything is on the table including tornadoes.  That said all the ingredients need to come together for widespread severe weather outbreak. 

GENERAL OVERVIEW
A large complex of showers and thunderstorms is speeding through the Great Lakes.  This complex has a history of producing wind gusts over 74 MPH.

NWS Great Lakes regional radar 238 EDT

Here are the storm reports so far

SPC Storm reports for Monday (as of 341 PM)

At the surface we see a wave of low pressure and an accompanying warm front forcing its way through Michigan.

WPC surface analysis 2 PM

This is being driven by a potent shortwave in the middle levels of the atmosphere.  It is sliding above a mid level ridge in the southwest

12z NAM 500 mb vort, heights 2 PM Mon (image NCEP)

By tomorrow afternoon the upper air pattern will evolve into this

12z NAM 500 mb vort, height 2 PM Tues (image NCEP)

The surface chart will look like this

WPC projected surface chart Tuesday 2 PM

This puts NH, VT, western ME, and all of Southern New England in the warm sector.  The orientation of the upper air will allow for a surge of low level moisture into the region.  Remember thunderstorms need a trigger, a source of low level moisture, and an unstable atmosphere.  We have the trigger (the cold front) and the low level moisture.  High resolution guidance is indicating dew points in the low 70's tomorrow afternoon

12z NAM hi-res 2 m dew points  Tuesday 5 PM (image Weatherbell)

 High temperatures at the same time will surge into the upper 80's.  So all we need to do is have some cooling in the middle layers of the atmosphere to make it unstable and allow for the cumulus clouds to tower high up into the atmosphere.   Clear skies tomorrow morning/early afternoon will be an indication of whether or not we see a big time severe weather event or just some isolated severe thunderstorms.  The SPC has areas north of the Pike, west of 495/395 in an enhanced severe weather risk meaning scattered to widely scattered severe thunderstorms capable of large hail, damaging wind, and isolated tornadoes is likely.

SPC Tuesday severe weather outlook

That's really all for now.  We (meteorologists) need to see what the atmosphere and radar look like tomorrow morning to know for sure.  What we do know is that a significant event is possible.  Stay weather alert tomorrow.

I'll have an update as early as possible tomorrow AM.

-Zack Green

Showers Possible This PM, Tropical Storm Bill Forms

While we would like to sun the today, leftover clouds from yesterday will help to limit the potential for thunderstorms this afternoon.  The big weather story is in Texas where Tropical Storm Bill formed last night and will bring heavy rain and gusty winds to the Central/Northern Texas coast.  By Sunday the remnants of Bill may bring periods of rain to Southern New England.  Until then we see mostly seasonable weather, with a chance of storms Thursday night.

GENERAL OVERVIEW
Here is the 5 am surface analysis from the Weather Prediction Center (WPC)

WPC surface analysis 5 am

The front south of New England has yet to lift north through the region.  It will as the trailing cold front moves east.  Here are the temperatures as of 7 am

7 am 2 m RTMA temperatures (image weatherbell)

By 8 PM tonight the trailing front will have swept offshore.

WPC Surface forecast 8 PM Tuesday

Before this front clears the region high temperatures should rise to around 80.

11z HRRR 2 m temps valid 2 PM (image weatherbell)

Some showers or weak thunderstorms are possible as the cold front moves through.  Lightning is always dangerous but I am not expecting hail or severe wind. 

11z HRRR Simulated Radar snapshot 6 PM (image weatherbell)

The SPC threat is much less than 2 days ago. 

Day 1 SPC severe weather outlook

TROPICAL STORM BILL
Here is Bill on the IR rainbow satellite

GOES_East Rainbow IR 745 am (NOAA)

The projected track curves the storm north into Oklahoma and then to the northeast into the Ohio Valley.  Interestingly enough the storm may hold itself together for awhile as it dumps a swath of heavy rain from Texas to Ohio.

NHC official track for Bill

Why the storm will hold together is ultimately unclear but there are several theories.  The truth is probably a blend of all three.  A lot of rain has already fallen in Texas and Oklahoma this spring so the soil is very moist.  A weak storm like Bill will be able to draw energy from this.  See this piece from Dr. Marshall Shepherd.  At the same time Bill is getting better organized as it makes it way to the coast so its core is stronger.  Also the storm will have favorable upper atmosphere dynamics to work with.  Ridges of high pressure will be present on either side of the system.

06z NAM 500 mb vorticity Wed 8 am (image NCEP)

Social media has turned meteorology into high school with grown ups arguing over whose theory is correct.  Few choose to step back and say "maybe we both are correct."  The bottom line is that while its scientifically interesting that the storm will be able to hold some strength well inland, the impacts are the same- RAIN.  Here are the 7 day totals

WPC 7 day rainfall estimates

I'm still working out how this will impact New England.  My guess is that it will interact with a cold front and we end up with more precipitation on Sunday/Monday than the WPC anticipates at the moment. 

Maybe some storms Thursday night but the rest of the week looks good, as do Friday/Saturday.  Saturday partly cloudy high around 80.

Thanks for reading
-Zack Green

Welcome Rain Monday

After temperatures in the 80s today high pressure will slide offshore and a front will bring welcome rains to the region overnight tonight into tomorrow.  Warm temperatures return Tuesday with the threat of thunderstorms, although the greatest potential appears to be in Eastern NY and Western MA/NW CT.  As the week progresses a weak tropical system will likely impact the Texas coast.  It will be embedded in the jet stream and may enhance precipitation in our region late this weekend.

WPC surface analysis 11 am, issued 1230 PM

Temperatures as of 1 PM were in the upper 70s/low 80s

RTMA 2 m temperatures 1 PM (image Weatherbell)

Light rain will break out around 10-11 PM from west to east.  Heavy rain will arrive just in time for the lovely Monday morning commute.

12 z Hi res NAM simulated radar 7 am Monday (image Weatherbell)

Anyone who has to use our wonderful interstate system to go to work knows what the combination of Monday, heavy rain, and rush means.  Give yourself extra time.  Here is the projected surface chart at 8 am.

WPC projected surface chart 8 am Monday

 Notice the red warm front to the southwest of New England.  High temperatures tomorrow will struggle to reach 60 in a lot of areas.  Thankfully this is short lived.  Notice the 90's in Central NJ, 50's in MA! Also notice the low in the Gulf of Mexico.

12z Hi Res NAM 2 m temps 2 PM Monday (image Weatherbell)

 The low in the Gulf of Mexico may become a tropical depression or a weak tropical storm.  It doesn't really matter because whatever it is it has a deep tropical connection and it is expected to bring heavy rain to parts of Texas that do not need it.  I don't expect a repeat of Tropical Storm Allison in 2001 but there could be more serious flooding in SE Texas northward up into Oklahoma.  The disturbance is not terribly impressive at the moment

GOES_east IR rainbow satellite image 145 PM (image NOAA)

But by Tuesday morning it should be near the Texas coast and should be a little better organized.

WPC projected surface chart 8 am Tuesday

Rain in Southern New England ends tomorrow late afternoon/evening.  The heaviest rain is over early afternoon.  1-2 inches of rain is likely regionwide.

48 hour rainfall ending 8 am Tuesday (image WPC)

Now this is where it gets interesting.  The storm prediction center (SPC) suggests a isolated risk of severe weather on Tuesday.  I don't buy it for Southern New England except maybe the far western counties of MA and CT.  I believe the threat is more PA/NY/NJ.

SPC Day 3 severe thunderstorm outlook Tuesday

Wednesday is around 80 and sunny, Thursday a chance of showers, Friday and Saturday look ok.  Sunday could be questionable as the leftovers of the tropical system (probably named Bill) will be close.  I have a very important forecast on Saturday as my cousin Kate is getting married (to a Bill no less).  I told her 83 and partly cloudy so Tropical Storm Bill will not be welcome.  7 day rain totals

WPC 7 day rain totals ending Sunday 7 am

We need it.  Last weeks rain dented the drought but it did not erase it.

US drought monitor issued June 9, 2015 (NOAA)

Sing it Luke

Have a good Sunday

-Zack Green

UPDATE 320 PM-Severe Thunderstorms Possible Today

 The Storm Prediction Center in Norman, OK has issued a SEVERE THUNDERSTORM WATCH for Central and Western New England

Severe Thunderstorm Watch 280 (SPC)

The cold front is pushing east and is entering a somewhat favorable environment for thunderstorms.  A strong line of storms has exploded in the Hudson River Valley heading towards Western MA/VT/NW CT

NWS Northeast regional radar loop 248 PM

Damaging wind and isolated severe hail will be the main threats.  Perhaps a micro-burst or two with the warm moist environment that is in place.  The best threat looks to be Springfield to Worcester to Nashua, NH north and west.  Keep an eye to the sky as it may impact areas like the Blackstone Valley and Merrimack Valley.  Boston should be fine. The threat relaxes early this evening (8 PM latest). 

Previous discussion below
On this date 62 years ago the worst tornado in New England history ripped through Worcester, MA.  94 people lost their lives.  A separate tornado ripped through Sutton, Northbridge, and Mendon.  Thankfully the towns were not as densely populated (specifically Northbridge) in 1953 as they are today and no one was killed.  I can't see anything like that happening today but we will face the threat of severe weather, especially outside of 495.

NWS Northeast regional radar through 630 am

As of 630 there was solid rainfall in upstate New York and parts of Northern New England.  Warm and muggy air is present ahead of this cold front heading through Western PA and NY.

WPC 5 am surface analysis

Temperatures are not bad, most of Southern New England is in the mid 60's as of 6 am and climbing

6 am 2 m temperatures

Dew points are also in the 60's

11z HRRR 7 am dew points (image weatherbell)

 Dew points will rise into the mid 60's as the front approaches this afternoon.  Temperatures should rise into the upper 70's and maybe low 80's if we can get some sunshine.   If we do get sunshine the threat if severe weather will increase.  As of now Northern CT and Western MA face the greatest risk of severe storms.

SPC 2 am thunderstorm outlook

The front will clear tonight leaving temperatures around 80 and dew points in the upper 50's tomorrow.  Another threat of thunderstorms exists for Thursday as a another cold front approaches from the Great Lakes.

WPC surface forecast Wednesday 8 am

I'll update with any severe weather watches this afternoon.

-Zack Green