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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Not sure if this has been posted yet, so I'll post it again. I found it funny.

Member Since: July 6, 2010 Posts: 109 Comments: 30283
995 WxGeekVA: ...this girl I met at weather camp last year at Penn State. I wish she didn't live halfway across the country...
1011 WxGeekVA: I'm going out stormchasing next spring there, so I want to hang with her then. I hope it works out, I like everything about her. Sucks I only got to hang for a week last time.

Just remember, "...brains... I want your brains... brains..." ain't a good pickup line.
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Quoting AussieStorm:

Yep, I'm here. A balmy 58.3°F after an overnight low of 39°F.

Hey, Aussie. How you doing?
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Ah stick'in great another nasty line of storms coming my way...
Quoting VAbeachhurricanes:
Wind:


Hail:

What day is that for?.
Member Since: August 14, 2010 Posts: 10 Comments: 15734
Quoting Ameister12:
Anybody here?

Yep, I'm here. A balmy 58.3°F after an overnight low of 39°F.
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Anybody here?
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Pictures I took from Friday's derecho.




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1046. Grothar
Quoting reedzone:


Here's the thing... Beryl in 2006 developed off a mass of convection that came off of North Carolina... Current wind shear is 5-10 knots off the East Coast... If this persists, we may need to watch for tropical development.


I remember you called that one. I remember we were watching a blob cross the country and it moved over into the Atlantic. (but I saw it first.:P)
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Quoting VR46L:


I wont post the shower curtain version lol


You know what would be cool though?

If they made shower curtains with the image posted on them.

Weather geeks the world over would have to have them.

Happy Birthday Grothar. Nice and quiet on my side of Florida tonight, anyway.

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Member Since: July 6, 2010 Posts: 109 Comments: 30283
Quoting reedzone:


Here's the thing... Beryl in 2006 developed off a mass of convection that came off of North Carolina... Current wind shear is 5-10 knots off the East Coast... If this persists, we may need to watch for tropical development.
Hope it develops into Ernesto.
Member Since: October 15, 2011 Posts: 0 Comments: 3707
Reminds me of Friday... The mets were saying they thought it would weaken but then it didn't...
Member Since: September 3, 2011 Posts: 13 Comments: 3466
Quoting AussieStorm:

Nice cloud. How is everyone coping with the high heat? Staying nicely hydrated or planning a holiday to Sydney?

Staying inside lol.
Member Since: July 6, 2010 Posts: 109 Comments: 30283
1040. hydrus
Quoting WxGeekVA:


Uh Oh Not Good... Just west of where I live too...
I worry for the folks who have damage and no power. Not to mention I have relatives in Richmond.
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1039. Grothar
Quoting VR46L:


Are you in mainland Europe ? because you are an hour ahead of me


Where are you?
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Quoting TropicalAnalystwx13:
We had a nice shelf cloud before the wimpy storms.


Nice cloud. How is everyone coping with the high heat? Staying nicely hydrated or planning a holiday to Sydney?


Looks like a nice storm complex moving through the NE CONUS. Stay safe.
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Wind:


Hail:

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SEL2

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 452
NWS STORM PREDICTION CENTER NORMAN OK
905 PM EDT SUN JUL 1 2012

THE NWS STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

EASTERN KENTUCKY
WESTERN MARYLAND
WESTERN AND SOUTHWESTERN VIRGINIA
EASTERN WEST VIRGINIA INCLUDING THE EASTERN PANHANDLE

EFFECTIVE THIS SUNDAY NIGHT AND MONDAY MORNING FROM 905 PM UNTIL
200 AM EDT.

HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 80
STATUTE MILES EAST AND WEST OF A LINE FROM 50 MILES WEST
NORTHWEST OF MARTINSBURG WEST VIRGINIA TO 60 MILES SOUTHWEST OF
BLUEFIELD WEST VIRGINIA. FOR A COMPLETE DEPICTION OF THE WATCH
SEE THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU2).

REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY
DO PRODUCE TORNADOES.

OTHER WATCH INFORMATION...CONTINUE...WW 445...WW 446...WW
447...WW 448...WW 449...WW 450...WW 451...

DISCUSSION...SEVERAL CLUSTERS OF THUNDERSTORMS ARE SPREADING ACROSS
EASTERN KY/WESTERN WV AND EASTERN OH...PRODUCING LOCALLY DAMAGING
WINDS AND HAIL. THESE STORMS WILL MOVE ACROSS THE WW AREA THROUGH
THE MID-LATE EVENING. AS USUAL...THERE IS UNCERTAINTY WHETHER
STORMS CAN MAINTAIN INTENSITY AS THEY MOVE ACROSS THE APPALACHIAN
MOUNTAINS INTO WESTERN VA. HOWEVER...MODERATE INSTABILITY AND A
SUBTLE SHORTWAVE TROUGH MOVING THROUGH THE AREA SUGGEST THE
POTENTIAL THAT STORMS WILL PERSIST FOR SEVERAL MORE HOURS.

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM
MOTION VECTOR 30035.


...HART
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1035. hydrus
This could be interesting.
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We had a nice shelf cloud before the wimpy storms.

Member Since: July 6, 2010 Posts: 109 Comments: 30283
Quoting Grothar:
Sorry if I posted that twice. It is after 3AM here. What do you expect!!!

If its 3am where you are then you must be in Eastern Europe as its not quite 3 am here yet and the ever attendant and intuitive Hydrus saw it before me as I'm a bit weary here too.
Are you on a sabbatical to the Eastern states or just flying over our zone?
A lot of smoke in the European air at the moment as fires are beginning to take control of lots of mountainous areas and no rain in sight of course.
Temps from 90 to 105/F in Spain this week and quite a lot of wind in the south to fan the flames.
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Uh Oh Not Good... Just west of where I live too...
Member Since: September 3, 2011 Posts: 13 Comments: 3466
Quoting PlazaRed:

A possible course in English grammar and spelling might be advantageous!
Added to the above, you might request her advise on any local issues, plus her general background interests so as you can research them on the Internet or better still with us here, (Much more fun,) Start by being intrigued by her knowledge of all things you are not too sure about and freely compliment her on her local knowledge, ( bound to work wonders,)
The main thing is not to appear too confident and ask advise on your theories.
Always bear in mind that the future of humanity is in your hands!

Whats happening with those wild fires out in the mid west area of the US? We have got some of several thousands of acres here in southern Europe and thousands of people have been evacuated in the Valencia area of Spain. Thing are so bad they are showing up clearly on the satellite photos here.


Yeah I suck at English... Always have... And great advice, I will take that under advisement.
Member Since: September 3, 2011 Posts: 13 Comments: 3466
1030. VR46L
Quoting spathy:


Thanks vr4
I keep forgetting where those things are.


Your welcome Spathy
Member Since: March 1, 2012 Posts: 0 Comments: 6623
968 Tropicsweatherpr:

Lessee 6 plus 8 plus 27 plus 34 plus 17 plus 5 equals 97
So 6% of 97% is about 1 June NamedStorm out of every 16 NamedStorms from June thru November.
We had 2 Named storms in June, so we can expect 32 NamedStorms between the end of May and the beginning of December.
The averages are agin us! Could be worse I s'pose...
... 3% of the Named Storms take place before June and after November: ie 1 in about 33 named storms.
Had 2 NamedStorms in May. Sose it could be 66 NamedStorms in the Atlantic during 2012.

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1026. hydrus
Quoting Grothar:
Sorry if I posted that twice. It is after 3AM here. What do you expect!!!
Its yo birthday, you should be up partying...More bad weather for folks that got whacked today..Day 2 convective outlook
National Weather Service Storm Prediction Center Norman OK
1208 PM CDT sun Jul 01 2012


Valid 021200z - 031200z


..there is a slight risk of severe thunderstorms across much of the middle Atlantic
region...


..there is a slight risk of severe thunderstorms from the eastern Dakotas into western
Upper Michigan...


...
The upper trough over the northestern U.S. Will begin to move eastward with axis
offshore by 00z. Modest northwesterly flow aloft will remain across New York/PA
southeastward into Virginia...with weaker northwesterly flow into the Carolinas but
relatively cool air aloft will remain. At the surface...pockets of
instability will remain from Ohio across WV and into Maryland...but some
early convection makes the forecast uncertain. Greater instability
will exist across the Carolinas and into Georgia.


To the west...a convectively enhanced disturbance associated with a
weak shortwave trough will weaken the ridge across the northern
plains...with storms persisting through the period...moving from ND
at 12z Monday into Upper Michigan by 12z Tuesday. Low pressure will move from northern
South Dakota/southern ND eastward across central Minnesota overnight...and the greatest storms
threat will be along and just north of the low track.


..WV/Maryland southward across the Carolinas...
Models indicate storms may be ongoing across portions of Ohio and WV
Monday morning. This activity...or at least outflow...may continue southeastward
across Virginia and NC...possibly regenerating during the afternoon with a
wind and hail threat. Other activity is expected to form within a
weak surface trough southwestward into SC and eastern Georgia. The steep lapse rate
environment and ample moisture will favor strong downbursts and
hail. Shear will be strongest across Maryland and eastern Virginia...and a few
supercells will be possible with large hail.
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1025. VR46L
Quoting Grothar:
Sorry if I posted that twice. It is after 3AM here. What do you expect!!!


Are you in mainland Europe ? because you are an hour ahead of me
Member Since: March 1, 2012 Posts: 0 Comments: 6623
Quoting Grothar:


You're not kidding VR. big ones



Here's the thing... Beryl in 2006 developed off a mass of convection that came off of North Carolina... Current wind shear is 5-10 knots off the East Coast... If this persists, we may need to watch for tropical development.
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1023. Grothar
Sorry if I posted that twice. It is after 3AM here. What do you expect!!!
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Quoting WxGeekVA:


I'm going out stormchasing next spring there so I want to hang with her then. I hope it works out, I like everything about her sucks I only got to hang for a week last time.

A possible course in English grammar and spelling might be advantageous!
Added to the above, you might request her advise on any local issues, plus her general background interests so as you can research them on the Internet or better still with us here, (Much more fun,) Start by being intrigued by her knowledge of all things you are not too sure about and freely compliment her on her local knowledge, ( bound to work wonders,)
The main thing is not to appear too confident and ask advise on your theories.
Always bear in mind that the future of humanity is in your hands!

Whats happening with those wild fires out in the mid west area of the US? We have got some of several thousands of acres here in southern Europe and thousands of people have been evacuated in the Valencia area of Spain. Thing are so bad they are showing up clearly on the satellite photos here.
Member Since: Posts: Comments:
1020. beell
Quoting Levi32:
Based on the meridional (north-south) component of the 650mb wind, there is only a weak tropical wave along 38W over the central Atlantic, and there appear to be no well-defined tropical waves over the African continent at this time (maybe a very low-amplitude one at 10W), so the prospects are rather low in the near future of a potent tropical wave coming westward and needing to be watched for tropical development.



You and the graphics, Levi-so cool! You will have quite the impressive skill set when it's all said and done. Folks will be standing in line to put you to work!

The monsoon could make that 10W wave look impressive for a couple days-until it runs off the west end.
Member Since: September 11, 2007 Posts: 137 Comments: 15353
They issued Severe Thunderstorm Warnings for those things?
Member Since: July 6, 2010 Posts: 109 Comments: 30283
1018. hydrus
Quoting WxGeekVA:


I'm going out stormchasing next spring there so I want to hang with her then. I hope it works out, I like everything about her sucks I only got to hang for a week last time.
I know your pain. If I only had a time machine how different my life might have been. Nice burst over Africa..
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1017. VR46L
Quoting mermaidlaw:
@ #960 Herbert boxes??


I wont post the shower curtain version lol


Link
Member Since: March 1, 2012 Posts: 0 Comments: 6623
1016. Grothar
Quoting VR46L:
there are some serious big blobs coming through the Mid Atlantic States at the moment..Be Careful folks




You're not kidding VR. big ones

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Okay, I got that from one of the vets here, can't remember who at the moment but if that's the case then okay. I haven't been reading any of his recent comments except for the one hydrus quoted; so I may well be wrong. Thanks for that update.
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1014. pcbhere
Temps have dropped from 103 to 84 degrees in the last 30 minutes here in Louisville, Ky. Storms to the north and hopefully, will be here soon. I was dancing on the front lawn with my dog yelling WOOT! WOOT!
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Quoting Levi32:
Based on the meridional (north-south) component of the 650mb wind, there is only a weak tropical wave along 38W over the central Atlantic, and there appear to be no well-defined tropical waves over the African continent at this time (maybe a very low-amplitude one at 10W), so the prospects are rather low in the near future of a potent tropical wave coming westward and needing to be watched for tropical development.



So Levi,Ernesto will have to wait until after Mid July as the earliest?
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@ #960 Herbert boxes??
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Quoting PlazaRed:

Yer,
You got to show a bit of enthusiasm.
After all she spent millions of years perfecting her genes so as you would be attracted to her, so you got to put in a bit of effort.
After all if you have got a few topics of interest you and communicate on, then why not consider heading out into her territory and sweeping streets or filling shelves at the local store to let her know you are more than a passing breeze in the night.
Might just work, after all we are all behind you and if you run into problems the whole of WU underground could come to your emotional rescue, maybe even will up the odd t'storm overhead for you as an added feature of general interest!


I'm going out stormchasing next spring there so I want to hang with her then. I hope it works out, I like everything about her sucks I only got to hang for a week last time.
Member Since: September 3, 2011 Posts: 13 Comments: 3466
storms look to be falling apart in ohio..
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Quoting WxGeekVA:


Not a bad idea, she might end up going to the smae college so there is hope there.



About 40 MPH, but it is slightly accelerating.

Yer,
You got to show a bit of enthusiasm.
After all she spent millions of years perfecting her genes so as you would be attracted to her, so you got to put in a bit of effort.
After all if you have got a few topics of interest you and communicate on, then why not consider heading out into her territory and sweeping streets or filling shelves at the local store to let her know you are more than a passing breeze in the night.
Might just work, after all we are all behind you and if you run into problems the whole of WU underground could come to your emotional rescue, maybe even will up the odd t'storm overhead for you as an added feature of general interest!
Member Since: Posts: Comments:
1008. hydrus
Quoting Levi32:
Based on the meridional (north-south) component of the 650mb wind, there is only a weak tropical wave along 38W over the central Atlantic, and there appear to be no well-defined tropical waves over the African continent at this time (maybe a very low-amplitude one at 10W), so the prospects are rather low in the near future of a potent tropical wave coming westward and needing to be watched for tropical development.

I hear weeping.
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Quoting WxGeekVA:


Uh Oh.... Please not again....

Well, if that first line went that high and was unable to break the cap... Thank God.. y'all are probably going to be OK.
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1005. Levi32
Based on the meridional (north-south) component of the 650mb wind, there is only a weak tropical wave along 38W over the central Atlantic, and there appear to be no well-defined tropical waves over the African continent at this time (maybe a very low-amplitude one at 10W), so the prospects are rather low in the near future of a potent tropical wave coming westward and needing to be watched for tropical development.

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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.