Extreme storms and extreme heat hit the U.S.

By: Dr. Jeff Masters , 5:50 PM GMT on June 30, 2012

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A violent line of organized severe thunderstorms called a derecho swept across the U.S. from Illinois to Virginia on Friday, damaging houses, toppling trees, bringing down power lines. The storms killed six people in Virginia, two in New Jersey, and one in Maryland, and left at least 3.4 million people without power. The thunderstorms in a derecho (from the Spanish phrase for "straight ahead") create violent winds that blow in a straight line. The traditional definition of a derecho is a thunderstorm complex that produces a damaging wind swath of at least 240 miles (about 400 km), featuring a concentrated area of thunderstorm wind gusts exceeding 58 mph (93 km/hr.) A warm weather phenomenon, derechos occur mostly in summer, especially June and July in the Northern Hemisphere. They can occur at any time of the year and occur as frequently at night as in the daylight hours. As seen on our wundermap with the "go back in time" feature turned on, Friday's derecho began near Chicago in the early afternoon, then marched east-southeast, peaking in intensity over Virginia and Washington D.C. on Friday evening. The derecho was unusually intense due to the extreme heat, which helped create an unstable atmosphere with plenty of energy to fuel severe thunderstorms.


Figure 1. Radar image from our wundermap with the "go back in time" feature turned on for 11 pm EDT Friday June 29, 2012, showing the derecho over Washington D.C. and Baltimore. Click on the "hour" button above the wundermap to advance the time by one hour to watch the progress of the derecho across the country.


Figure 2. NOAA's Storm Prediction Center (SPC) logged 871 reports of damaging winds on Friday. Twenty one of these reports were for winds over 80 mph. The highest wind gust was in Oswego, Illinois: 92 mph.



Figure 3. A dramatic change in the weather in Buckeye land: the temperature at Ohio State University in Columbus, Ohio dropped from 97°F to 68° after passage of Friday's derecho. The storm brought a wind gust of 82 mph to campus, and 0.86" of rain.

Historic heat wave topples Dust Bowl-era extreme heat records
A historic heat wave on a scale and intensity not seen in the U.S. since the great heat waves of the 1930s Dust Bowl era set new all-time heat records for at least ten major cities Friday. According to wunderground's weather historian Christopher C. Burt, fifteen of the 303 major cities he maintains records for on the wunderground extremes page have set all-time heat records in the past four days. The only year with more all-time heat records is 1936, when 61 cities set all-time heat records. In 2011, which had the 2nd warmest summer in U.S. history, only ten of the 303 cities set all-time heat records during the entire summer. With the the hottest month of the year (July) still to come, 2012 threatens to rival the great Dust Bowl summer of 1936 for extreme heat.

All-time records for any date tied or broken on Friday:

109° Nashville, TN (old record 107° 7/28/1952
109° Columbia, SC (old record 107° on two previous occasions)
109° Cairo, IL (old record 106° on 8/9/1930)
108° Paducah, KY (ties same on 7/17/1942
106° Chattanooga, TN (ties same on 7/28/1952)
105° Raleigh, NC (ties same on 8/21/2007 and 8/18/1988)
105° Greenville, SC (old record 104° 8/10/2007 although 106° was recorded by the Signal Service in July 1887)
104° Charlotte, NC (ties same on 8/9 and 10/2007 and 9/6/1954)
102° Bristol, TN (ties same on 7/28/1952-this site now known as `Tri-State Airport')
109° Athens, GA. This is just 1° shy of the Georgia state record for June of 110° set at Warrenton in 1959.

All-time state June heat records set Friday:

113° Smyrna, TN (old record 110° in Etowah in June 1936)
109° Cairo, IL (old record 108° in Palestine in June 1954)

Also of note: Atlanta, GA hit 104° (its all-time June record), and just 1° shy of its all-time record of 105° set on 7/17/1980. The forecast for Atlanta on Saturday calls for a high of 105°F, which would tie for the hottest day in the city's history.

Wunderground's weather historian Christopher C. Burt has a new post called The Amazing June Heat Wave of 2012 Part 1: The West and Plains June 23 - 27 summarizing the early portion of this week's historic heat wave. He plans to make a follow-up post on Sunday summarizing the records set on Friday and Saturday.

Relatively quiet in the Atlantic
An area of heavy thunderstorms, associated with an upper level low pressure system, has developed in the Gulf of Mexico along the Texas coast. This disturbance will probably move ashore over Texas before development into a tropical depression can occur, and NHC is giving it a 0% chance of development. The tropical wave approaching the Lesser Antilles (Invest 97L) has dissipated due to dry air, and is no longer a threat. None of the reliable computer models are developing anything during the next seven days.

Jeff Masters

Chicago Shelf (LarrySmit)
Chicago Shelf
Summer Heat (gardner48197)
Summer Heat
Smokey Clouds (LarrySmit)
Asperatus Clouds
Smokey Clouds
And the Sky Opened Up! (webgal)
Much needed thunderstorms came through west-central Illinois late this evening. The lightning was absolutely incredible!
And the Sky Opened Up!

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Quoting Dr. Jeff Masters:
The tropical wave approaching the Lesser Antilles (Invest 97L) has dissipated due to dry air, and is no longer a threat.
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97L may have been deactivated... It's floater is gone and there hasn't been an 18z update.
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I know someone had mentioned seeing the TIV on Lake Mary Blvd. yesterday. This is why:Link
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Quoting MAweatherboy1:

Good afternoon Nigel... It's making a big comeback, at least the daily is!

Yeah, that's a large spike in the daily SOI...from -49.35 a couple of days ago to 15.11
Quoting Tropicsweatherpr:


Good afternoon nigel. Wave just east of Lesser Antilles will not develop but I hope it brings some needed rain for some of the islands and when it reaches Eastern Jamaica the same.

I'm hoping for the same thing!
Member Since: November 6, 2010 Posts: 11 Comments: 8026
Quoting washingtonian115:
What does that mean?.

Solar flares are given intensity in 5 classes: A and B, which are very weak, C, which are minor, M, which are moderate, and X, which are major... So that was the second moderate flare today.
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Quoting xtremeweathertracker:


This little system kinda reminds me of Humberto!!!

it does just by the position
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21P
Member Since: November 6, 2010 Posts: 11 Comments: 8026
Quoting MAweatherboy1:
Second M class of the day... A sign of impending doom...

What does that mean?.
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If this system were out over the gulf a bit more, I believe it would develop nicely.
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Second M class of the day... A sign of impending doom...

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Quoting xtremeweathertracker:


This little system kinda reminds me of Humberto!!!


0% they say on it. None the less today if is giving us much needed rain in SE Texas! Stinging rain, rain that blows sideways....
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Quoting nigel20:
Good afternoon everyone!

Daily SOI: 15.1
30 Day SOI: -10.2
90 Day SOI: -6.0


Good afternoon nigel. Wave just east of Lesser Antilles will not develop but I hope it brings some needed rain for some of the islands and when it reaches Eastern Jamaica the same.
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Quoting nigel20:
Good afternoon everyone!

Daily SOI: 15.1
30 Day SOI: -10.2
90 Day SOI: -6.0

Good afternoon Nigel... It's making a big comeback, at least the daily is!
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Quoting STXHurricanes2012:
Oh my its really coming down hard!!!


This little system kinda reminds me of Humberto!!!
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Member Since: September 3, 2011 Posts: 13 Comments: 3471
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Quoting STXHurricanes2012:
Oh my its really coming down hard!!!
how much do ya need
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Good afternoon everyone!

Daily SOI: 15.1
30 Day SOI: -10.2
90 Day SOI: -6.0
Member Since: November 6, 2010 Posts: 11 Comments: 8026
86. mati
The storm around Washington also took out the Amazon data center... may explain connection problems


Link
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Caribbean Storm Update June 26th English & Espa%uFFFDol

Video Update


Blog Update






Video Update

Link


Link
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Oh my its really coming down hard!!!
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The Daily Wind-Up
NEW TROPICAL DISCUSSION OUT
AOI Near Texas Coast/ Invest 97L
http://035d83b.netsolhost.com/
Link
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Quoting DontAnnoyMe:


What makes you think that? I've never been banned. Just haven't been on much lately.

Normally when bloggers are gone for a long time they've either been banned or something has happened to them.
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Quoting Hurricanes101:


that was just before the decoupling heard around the world

TS Chris - 2006
yup...........lol
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Sorry things slowed down.........lol
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Quoting OrchidGrower:



Thought I could see a ULL feature on the infrared loop. I suppose the ULL will pull the Gulf low into Texas behind it?

yes most of the convection is mostly from that low but its interesting that wants to get a low at the surface but it maybe to late.
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TS Chris 8-2-2006
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Quoting TropicalAnalystwx13:
It is currently 103 °F with a heat index of 114 °F.
104 °F here with about the same heat index. We are supposed to get to 110 °F but the humidity should fall and stay around 20 when it gets there. Btw the 104 °F reading is an hour old it may be 110 already.
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Quoting WxGeekVA:
My dad and I decided not to clean up storm damage yet because of the threat for more later. Hopefully it doesn't happen but we don't want to waste our time. So then we wanted to go to the pool. We get there, and there is an oak tree in the pool and it's closed. And that's annoying, because it's already almost 95 degrees again.
you do know that if high winds of 75 mph or higher occur in other events the items left about will turn into projectiles and missles
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Quoting STXHurricanes2012:
Interesting 850 mb vorticity has increased alot with this recent update...blob off the tx coast...700 mb as well as 500 mb but still connected with the ull. just a thought
CAN YOU POST IT
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Quoting washingtonian115:
Don'tAnnoyMe I thought you were banned.


What makes you think that? I've never been banned. Just haven't been on much lately.

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Quoting STXHurricanes2012:
Interesting 850 mb vorticity has increased alot with this recent update...blob off the tx coast...700 mb as well as 500 mb but still connected with the ull. just a thought



Thought I could see a ULL feature on the infrared loop. I suppose the ULL will pull the Gulf low into Texas behind it?
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Quoting pottery:

Me too, for a while.
Been doing that since last night.
Power disruptions ?
had problems with my connection as well this morning but ok now
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Quoting HurricaneHunterJoe:
Prefer 97L look like this? No?


that was just before the decoupling heard around the world

TS Chris - 2006
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68. MZT
WU says 103 in Charlotte right now. It's 99 here at my desk. Objects in the house feel warm to the touch.
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Interesting 850 mb vorticity has increased alot with this recent update...blob off the tx coast...700 mb as well as 500 mb but still connected with the ull. just a thought
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Derecho: Behind Washington, D.C.’s destructive thunderstorm outbreak, June 29, 2012


This derecho event will likely to go down as not only one of the worst on record in Washington, D.C. but also along its entire path stretching back to northern Indiana.

As the intensity of the heat wave, without reservation, was a key factor in the destructiveness of this derecho event - it begs the question about the possible role of manmade climate warming (from elevated greenhouse concentrations). It’s a complicated, controversial question, but one that scientists will surely grapple with in case studies of this rare, extraordinary event.
Member Since: September 3, 2011 Posts: 13 Comments: 3471
Quoting HurricaneHunterJoe:
Prefer 97L look like this? No?
What storm is that?.
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that Texas low sure looks like is getting more organized to bad it is to close to land...
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Blog. Is. LAGGING!!!!
Member Since: September 3, 2011 Posts: 13 Comments: 3471
Quoting ycd0108:
Can not log in normally to WU just now.
Anyone happen to know what is going on?

Me too, for a while.
Been doing that since last night.
Power disruptions ?
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Quoting WxGeekVA:
My dad and I decided not to clean up storm damage yet because of the threat for more later. Hopefully it doesn't happen but we don't want to waste our time. So then we wanted to go to the pool. We get there, and there is an oak tree in the pool and it's closed. And that's annoying, because it's already almost 95 degrees again.

You know things are HOT when the Oak Trees start loitering in the swimming holes.....
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It is currently 103 °F with a heat index of 114 °F.
Member Since: July 6, 2010 Posts: 113 Comments: 32033
Can not log in normally to WU just now.
Anyone happen to know what is going on?
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Quoting CaicosRetiredSailor:


...and today's headline of note is:

Archaic pottery could change history of mankind


: )

Hmmm!

I've never been called archaic before.
Does that mean I'm older than I used to be?

:):))

Interesting article though.
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Now its coming down hard!!!
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Quoting KEEPEROFTHEGATE:
naw iam moving to greenland as soon as the ice melts

Well you better start packing...
won't be long now.
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currently 103-104 at my house, supposed to feel hotter tomorrow with more moisture, might even be a storm or 2 from a SW propagating storm cluster:


yesterday it was 104F felt like 102F at atlanta, currently it is 102 feels like 104F

out in Athens GA it is 102 feels like 106, supposed to reach 110 feels like 115
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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.