Severe thunderstorms erupt along a swath 1,500 miles long, killing 2

By: Dr. Jeff Masters , 2:48 PM GMT on July 27, 2012

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A huge outbreak of severe thunderstorms hit the nation on Thursday, causing damage in fifteen states and knocking out power to over 250,000 customers. Two people were killed, one by a falling tree in Pennsylvania, and one due to a lightning strike in New York. Two possible tornadoes touched down: one in Elmira, New York and another in Brookville, PA. The severe storms covered an unusually large area, erupting along a 1,500-mile long swath of the country from Texas to Connecticut. The intensity of the thunderstorms was increased by a very hot and moist airmass; temperatures in the mid to upper 90s were common across the region Thursday. A number of record highs for the date were set, including a 98° reading at Washington D.C.'s Dulles Airport. The threat of severe weather continues for Friday afternoon over portions of the Ohio Valley and mid-Atlantic, as NOAA's Storm Prediction Center has placed these regions in their "Slight Risk" area for severe thunderstorms.


Figure 1. A rare sight: at 7 pm EDT on July 26, 2012, severe thunderstorm warnings were in effect for 132 counties in 15 states along a swath 1,500 miles long.


Figure 2. Visible satellite image taken at 7:02 pm EDT July 26, 2012, of the line of severe thunderstorms that extended from Texas to Connecticut. Image credit: NASA/GSFC.


Figure 3. An imposing sight: A squall line of severe thunderstorms with two bowing segments takes aim at New York, Connecticut, and New Jersey on July 26, 2012. The tip of a bow echo typically has the most violent winds in a severe thunderstorm.

Was Thursday's outbreak a derecho?
Thursday's outbreak of severe thunderstorms was not nearly as violent as the June 29 - 30 Mid-Atlantic and Midwest derecho, since the atmosphere wasn't as unstable. The June 29 storm was one of the most destructive and deadly severe thunderstorm complexes in North American history. It killed 22 people, knocked out power to at least 3.7 million customers, and did hundreds of millions in damage. There were 871 reports of damaging winds logged by the next day, and 36 of the thunderstorms had wind gusts in excess of hurricane force--74 mph. In contrast, yesterday's event had only two thunderstorms with wind gusts in excess of 74 mph, and 383 reports of damaging winds. We can probably classify yesterday's severe thunderstorm event as a weak derecho, since it met the main criteria, as defined by NOAA's Storm Prediction Center: "A derecho is a widespread, long-lived wind storm that is associated with a band of rapidly moving showers or thunderstorms. Although a derecho can produce destruction similar to that of tornadoes, the damage typically is directed in one direction along a relatively straight swath. As a result, the term "straight-line wind damage" sometimes is used to describe derecho damage. By definition, if the wind damage swath extends more than 240 miles (about 400 kilometers) and includes wind gusts of at least 58 mph (93 km/h) or greater along most of its length, then the event may be classified as a derecho."


Figure 4. NOAA's Storm Prediction Center logged 374 reports of damaging winds from Thursday's severe thunderstorms. Two of these thunderstorms had winds in excess of hurricane force (65 knots, or 74 mph.)


Figure 5. The climatology of derecho events over the U.S. Image credit: NOAA Storm Prediction Center.

Quiet in the Atlantic
There are no tropical cyclone threat areas to discuss in the Atlantic. A strong tropical wave is expected to bring heavy rains to the Lesser Antilles Islands and Puerto Rico on Monday and Tuesday, but none of the models are developing the wave. The NOGAPS computer model is suggesting development of a second tropical wave between Africa and the Lesser Antilles Islands August 2 - 3.

Have a great Olympic weekend, everyone, and I'll be back Monday with a new post.

Jeff Masters

Intense (jerseyshoretoo)
We had high winds and heavy rain, but fortunately not serious damage. Prayers for everyone in the path of this massive storm.
Intense
Crazy Lightning in Rhode Island (ExitPupilCreative)
Lightning from storms that slammed the Northeast today. This is at Charlestown Beach in Charlestown, Rhode Island.
Crazy Lightning in Rhode Island
BeforeTheStorm (CalicoBass)
at times there were gust of wind that would stir up the dirt as you can see to the right in this photo. We finally got a real good rain that lasted a while. Was under one Severe Thunderstorm Warning.
BeforeTheStorm
Swirling clouds (Crisred)
As the strom approaches the clouds are rolling over themselves and swirling into each other. Rapidly!
Swirling clouds
Shelf Cloud over the Bronx (JimTheWunder)
Taken just before thunderstorm.
Shelf Cloud over the Bronx

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Quoting TropicalAnalystwx13:

The Hurricane Specialist Unit..

My name will be up there someday. Below Kori's.
Member Since: July 6, 2010 Posts: 113 Comments: 34473
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This season is so dead we are looking at a flare up the size of a pin head craziness....
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Yes well said, best described as "English" is right on. Which is the point, most just don't get the Brit's. :) Even though I'm from Celtic decent, I don't get the Brit's generally.
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Quoting stormchaser19:


who is the person that, made the advisories? and them approves

The Hurricane Specialist Unit..
Member Since: July 6, 2010 Posts: 113 Comments: 34473
Quoting stormchaser19:


who is the person that, made the advisories? and them approves


Uh... it depends?
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Quoting TropicalAnalystwx13:

Knabb isn't the one that does the TWO.


who is the person that, made the advisories? and them approves
Member Since: June 20, 2012 Posts: 0 Comments: 2194
Quoting Grothar:
Anyone watching the opening of the Olympics? One word. "Bizarre".

I believe the wave to watch is the 2nd one. That has the best chance of development. I believe the first one will have to much dry air around it. The second wave should be near the Antilles or by the Antilles by the end of next week.


So I guess your watching a replay. It finished about 90mins ago. I would describe it as English.
Member Since: September 30, 2007 Posts: 9 Comments: 16017
Prob with the Olympics in the UK, is aside from football (soccer), they're as a whole, not terribly into sports. And most team GB is 'posh sports' since it's not a very althetic nation and usually a relatively small team. I think it's best held in a country where people who live there are really likely to go and are into it...doesn't mean should only be held in places like that, just think it's better where there's more general support and interest. People will get behind it more if there's a few high profile medals though....and I think Romney has inadvertantly caused some puffed out chests of pride LOL But in the UK, elementary kids don't even have P.E everyday or much of sports in school, I've always thought they're really missing out compared to what I had in Ca...albeit the weather WAS much better!

Anyway, on the main tropical page, it's saying the invest in EPac has 90 mph winds!? That's some invest then! LOL
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Quoting Gearsts:
Ouch!


Hmmmm our wave doesn't look too good there. Lol. Puts it in perspective. :)
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Quoting AussieStorm:


Sorry, but, If Australia beats USA in any sport, you'll all hear about it. Like tonight we have Golden Girl Stephanie Rice in the Women's 400m Individual Medley(Swimming).

GOM/BOC

Loop
I always watch the Aussie swimmers. They usually get plenty of Olympic medals in swimming I believe. You'd know better, of course. I'd rather not know till I watch. It's admittedly a situation we never had before the Internet, and I understand however you feel. Good luck to the Golden Girl.
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Quoting Tropicsweatherpr:


We have Culson in 400 meters as one of the favorites for gold medal.

Yeah, Culson is running well.
Good luck to him!
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Quoting stormchaser19:
NHC Director, Dr. Rick Knabb,looks like he doesn't like the yellow circles



Knabb isn't the one that does the TWO.
Member Since: July 6, 2010 Posts: 113 Comments: 34473
Quoting pottery:

"Different" also comes to mind.
For the most part, I thought it was great.
But the "Arctic Monkeys" were pretty dismal.

Looking forward to the next 2 weeks, especially the Cycling (we should medal there), and the womens and mens sprints (100, 200, 400 meters). May be an all Caribbean finals in those!
Not seeing too many US hopes in there.....


We have Culson in 400 meters as one of the favorites for gold medal.
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Quoting Grothar:
Anyone watching the opening of the Olympics? One word. "Bizarre".

I believe the wave to watch is the 2nd one. That has the best chance of development. I believe the first one will have to much dry air around it. The second wave should be near the Antilles or by the Antilles by the end of next week.


"Different" also comes to mind.
For the most part, I thought it was great.
But the "Arctic Monkeys" were pretty dismal.

Looking forward to the next 2 weeks, especially the Cycling (we should medal there), and the womens and mens sprints (100, 200, 400 meters). May be an all Caribbean finals in those!
Not seeing too many US hopes in there.....
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Ya Grothar, bizarre is a good word for it. Not liking it at all compared to the last two openings. Love the Brits, but wow this is out in left field a bit. They are trying too hard when it's not bizarre. I do love the competition though. They gave us Churchill, so I guess we can forgive this.
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Ouch!
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Anyone watching the opening of the Olympics? One word. "Bizarre".

I believe the wave to watch is the 2nd one. That has the best chance of development. I believe the first one will have to much dry air around it. The second wave should be near the Antilles or by the Antilles by the end of next week.

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Quoting Tazmanian:



thanks


You're welcome. :)
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NHC Director, Dr. Rick Knabb,looks like he doesn't like the yellow circles


Member Since: June 20, 2012 Posts: 0 Comments: 2194
Quoting Tropicsweatherpr:
JB made a tweet about wave.



Forgive me if this was posted already. From 2pm marine discussion NHC. Hopefully means some rain for those that need it.

CARIBBEAN SEA AND TROPICAL N ATLC W OF 55W...
HIGH PRES N OF THE AREA HAS BUILT IN BEHIND THE TROPICAL WAVE
MOVING THROUGH THE YUCATAN. THIS HIGH PRES IS MAINTAINING FRESH
TO STRONG E-NE WINDS ACROSS THE BASIN...WITH THE 0238 UTC ASCAT
PASS SHOWING NEAR GALE FORCE WINDS OFF THE COAST OF COLOMBIA.
THE GFS IS DOING A REASONABLY GOOD JOB DEPICTING THESE TRADE
WINDS. LOOK FOR WINDS TO BACK OFF A NOTCH OVER THE NEXT TWO DAYS
AS THE NEXT TROPICAL WAVE ENTERS THE CARIBBEAN AND DIMINISHES
THE PRES GRADIENT. THIS TROPICAL WAVE LIES ALONG 55W. THIS WAVE
WILL CONTINUE WESTWARD THROUGH THE TROPICAL N ATLC TODAY INTO
EARLY SAT MORNING...THE E CARIBBEAN SAT AFTERNOON THROUGH
SUN...AND INTO THE WEST CARIBBEAN MON AND TUE. THE WAVE IS
EMBEDDED IN AN AREA OF DRY AIR AND AFRICAN DUST THAT IS
INHIBITING CONVECTION. WINDS ARE ONLY A MODERATE BREEZE WITH THE
SYSTEM. A SIMILAR AIRMASS IS ALSO IMPACTING THE TROPICAL WAVE
ALONG 37W. THE CYCLONIC CIRCULATION ASSOCIATED WITH THIS WAVE IS
VERY BROAD AND IS BEGINNING TO PICK UP MORE MOISTURE.
SOME
MODERATE CONVECTION AND LIGHTNING ARE NOW NOTED ALONG THE WAVE
FROM 15N-16N. THE 1148 UTC ASCAT PASS SHOWS AN AREA OF 20 KT NE
WINDS PRIMARILY W OF THE WAVE FROM 15N TO 19N. THE MODELS SHOW
THIS AREA OF WINDS EXPANDING AS THE WAVE MOVES W. THE 06Z GFS
AND 00Z UKMET HAVE BACKED OFF ON THE DEVELOPMENT OF A
WELL-DEFINED LOW PRES SYSTEM FROM THIS WAVE LIKE EARLIER RUNS
HAVE SHOWN. THIS IS A TREND TOWARD THE MORE OPEN WAVE SEEN IN
THE ECMWF. THESE THREE MODELS REMAIN IN REASONABLE AGREEMENT ON
THE TIMING OF THE SYSTEM. THE GRIDS WERE ADJUSTED TOWARD A BLEND
OF THE 06Z GFS AND THE MORE CONSISTENT 00Z ECMWF.
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Quoting AtHomeInTX:


Local ABC affiliate. Link



thanks
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Quoting CosmicEvents:
I was just joking. It's easy enough to find out though, for those who want to know before you watch. The opening ceremonies are just pageantry, but once the competition starts I'd rather not know the result before I watch. Hopefully nobody will let the results known at that time.


Sorry, but, If Australia beats USA in any sport, you'll all hear about it. Like tonight we have Golden Girl Stephanie Rice in the Women's 400m Individual Medley(Swimming).

GOM/BOC

Loop
Member Since: September 30, 2007 Posts: 9 Comments: 16017
Quoting Tazmanian:




where did you get this info from?


Local ABC affiliate. Link
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Quoting Articuno:
I love mr bean lol


Agreed. Mr. Bean is the best! Evening everyone
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Quoting AtHomeInTX:


Would seem my local met agrees. Although I just want to add we had a mild, wet winter last year. I can live with that. :)


Weak El Nino develops
Posted: Jul 26, 2012 8:15 PM CDT Updated: Jul 26, 2012 8:24 PM CDT
By Patrick Vaughn


Sea Surface Temperatures (SST) in the Eastern Pacific have warmed to at least 0.5 C above-normal. Thus, an El Nino has formed.

The forecast is for El Nino to persist as the forecast models continue to show an upward trend.

All areas of the Eastern Pacific which are used in forecasting such an event show and upwards trend or warming.

This is the exact opposite to last year's La Nina with below-normal Sea Surface Temperatures.

Why is this important? Well, it will assist in increasing the trade winds and upper-level shear in the Atlantic during the Peak of Hurricane Season. This should work to reduce the number of hurricanes and possibly the severity of the storms during the Peak.

In addition, it also means that more-than-likely, Texas will see a wet, mild Winter.




where did you get this info from?
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Quoting GeorgiaStormz:


just give the US one, we would really make something super
We would have to borrow the Money from China!!
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JB made a tweet about wave.

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Shear will change IMO the Weatern Card. and the BOC will be the place to watch late Sept. & Oct. and Andrew formed north of the islands and than tracked due weast over S/Fl. into the Gulf anything can happen.If the waves move north of the islands the B-high will push them back to the west!!
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I love mr bean lol
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Quoting AtHomeInTX:


Hmmm? I don't know. He linked CPC. But the discussion was on July 5. Link


The Monthly update of August will be released on the 9th. Let's see if they declare El Nino official by then or they wait until the September one.
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OMG there was a 100 foot tall Mitt in the stadium scaring the kids about free healthcare

On a lighter note the weather was bleeping hot today in south FL....please send us a clouds tomorrow. This SAL stinks.
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Quoting OracleDeAtlantis:
There is a considerable amount of angular momentum with this new flare up in the central Atlantic. It's surrounded by dry air, but not at all layers.


If there is enough dry air aloft to evaporate clouds and cause downdrafts of cold air, that's enough to dampen tropical development. (Headline: dry air dampens development.)
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Quoting Tropicsweatherpr:


But Climate Prediction Center has not declared El Nino official yet.


Hmmm? I don't know. He linked CPC. But the discussion was on July 5. Link
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When will Central Atlantic wave be tagged as invest?

A-Sometime on Saturday.
B-Sometime on Sunday.
C-Sometine after Monday.
D-Never will be a invest.

I say B.
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Quoting AtHomeInTX:


Would seem my local met agrees. Although I just want to add we had a mild, wet winter last year. I can live with that. :)


Weak El Nino develops
Posted: Jul 26, 2012 8:15 PM CDT Updated: Jul 26, 2012 8:24 PM CDT
By Patrick Vaughn


Sea Surface Temperatures (SST) in the Eastern Pacific have warmed to at least 0.5 C above-normal. Thus, an El Nino has formed.

The forecast is for El Nino to persist as the forecast models continue to show an upward trend.

All areas of the Eastern Pacific which are used in forecasting such an event show and upwards trend or warming.

This is the exact opposite to last year's La Nina with below-normal Sea Surface Temperatures.

Why is this important? Well, it will assist in increasing the trade winds and upper-level shear in the Atlantic during the Peak of Hurricane Season. This should work to reduce the number of hurricanes and possibly the severity of the storms during the Peak.

In addition, it also means that more-than-likely, Texas will see a wet, mild Winter.


But Climate Prediction Center has not declared El Nino official yet.
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Almost to August and u see it......I suspect the Caribbean is quiet till oct
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Quoting Levi32:


I'm not talking about a specific wave here, just the general pattern. It's too hard to say yet what will become of these next two waves specifically.

El Nino has already likely been responsible for the increase in wind shear (mainly from stronger trade winds) in the Caribbean relative to the last 2 seasons so far. El Nino is already having a significant impact. It's here. This is an El Nino hurricane season.


Would seem my local met agrees. Although I just want to add we had a mild, wet winter last year. I can live with that. :)


Weak El Nino develops
Posted: Jul 26, 2012 8:15 PM CDT Updated: Jul 26, 2012 8:24 PM CDT
By Patrick Vaughn


Sea Surface Temperatures (SST) in the Eastern Pacific have warmed to at least 0.5 C above-normal. Thus, an El Nino has formed.

The forecast is for El Nino to persist as the forecast models continue to show an upward trend.

All areas of the Eastern Pacific which are used in forecasting such an event show and upwards trend or warming.

This is the exact opposite to last year's La Nina with below-normal Sea Surface Temperatures.

Why is this important? Well, it will assist in increasing the trade winds and upper-level shear in the Atlantic during the Peak of Hurricane Season. This should work to reduce the number of hurricanes and possibly the severity of the storms during the Peak.

In addition, it also means that more-than-likely, Texas will see a wet, mild Winter.
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738. JLPR2
Quoting Tropicsweatherpr:


Yep,between Monday thru Tuesday the NE Caribbean islands will get a good deal of rain from this. Let's see if is only that or it surprises us with more?


I guess a weak TS wouldnt be that bad. One can dream...

The Atl says: No storms till August, WU, deal with it!

XD
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Quoting JLPR2:


Yes, it's moistening the area, it might bring some decent showers to islands and the NE Caribbean islands need it.


Yep,between Monday thru Tuesday the NE Caribbean islands will get a good deal of rain from this. Let's see if is only that or it surprises us with more?
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Quoting floridaboy14:
dont forget its over 10 days out and we dont know what the shear will be by then. shows the ridge is strong and will send these strong waves into the carribean. this one develops east of the islands. next run could show west of the islands. i know the carribean isnt favorabe till mid august usually but will el nino have a SIGNIFICANT impact on the shear in the carribean?


I'm not talking about a specific wave here, just the general pattern. It's too hard to say yet what will become of these next two waves specifically.

El Nino has already likely been responsible for the increase in wind shear (mainly from stronger trade winds) in the Caribbean relative to the last 2 seasons so far. El Nino is already having a significant impact. It's here. This is an El Nino hurricane season.
Member Since: November 24, 2005 Posts: 635 Comments: 26775
Quoting GeorgiaStormz:


a fake queen parachuted in

and i hear the drummers got uite a workout

10,000 people and no leaks, wow
I was just joking. It's easy enough to find out though, for those who want to know before you watch. The opening ceremonies are just pageantry, but once the competition starts I'd rather not know the result before I watch. Hopefully nobody will let the results known at that time.
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wow, the rings were amazing, this my first opening ceremony, i missed beijing

but on a weather note, apparently they had rain before the ceremony, but none during it.
Member Since: February 11, 2012 Posts: 0 Comments: 9770
There is a considerable amount of angular momentum with this new flare up in the central Atlantic. It's surrounded by dry air, but not at all layers.

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Dr. Masters co-founded wunderground in 1995. He flew with the NOAA Hurricane Hunters from 1986-1990. Co-blogging with him: Bob Henson, @bhensonweather

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