Extreme storms and extreme heat hit the U.S.

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

Share this Blog
40
+

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!

Reader Comments

Comments will take a few seconds to appear.

Post Your Comments

Please sign in to post comments.

or Join

Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 955 - 905

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25Blog Index

I see why the SPC couldn't put out at least a moderate warning, it would have been for a thousand mile stretch from the Carolina's all the way to Central Illinois. Would have looked wild and threatening though; and this day has been that again.
Member Since: April 18, 2012 Posts: 0 Comments: 2437
Looking at the entire US radar loop, it almost looks likes the lines of storms in NC and in Ohio are moving like spokes on a wheel. The center of the wheel being in GA.
Member Since: Posts: Comments:
Quickly approaching five hundred SW reports and it's just past peak heating. Broken line heading west of Columbus, Ohio and southward are producing an increasing line of strengthening storms. Let's hope it remains a broken line.
Member Since: April 18, 2012 Posts: 0 Comments: 2437
Quoting reedzone:
Yep, this is a developing derecho, the line is now starting to bow.. It's gonna be a long day for people in the Ohio Valley.


BOOOOOO! Turn it off!
Member Since: Posts: Comments:
Quoting aspectre:
Remind you of anyone?



SpiderLizard!
Member Since: Posts: Comments:
Quoting Ameister12:
These nasty storms are heading for Wilmington.

I'm out for now. Stay safe.


In Wilmington, we dont even get interested unless its a hurricane approaching Cat 4. Remember....we are toast.
Member Since: Posts: Comments:
Quoting Grothar:


Good thing you stopped at four greats. But last March I did become a great-great-great Uncle for real. My one twin nephew became a great-grandfather.
Whoa....Happy Birthday, Grothar.
Member Since: Posts: Comments:
Atlanta GA reached a high of 106F today, which ties the all time high of 106F which was set yesterday.

However, today was more humid, leading to higher heat indices.
Tomorrow is expected to be cooler, around 100F
Member Since: February 11, 2012 Posts: 0 Comments: 9725
Spaceflight Now | Breaking News | Watchdog agency warns of dangerous weather data gap
Forecasters will almost certainly face gaps in weather data before NOAA's next-generation polar-orbiting satellites begin launching in 2017, government officials told Congress this week.

Mounting costs and satellite development delays will likely mean NOAA's next polar-orbiting weather satellite will launch after its current operational spacecraft is retired, officials said.

Kathryn Sullivan, NOAA's deputy administrator, said studies show weather prediction would suffer without complete atmospheric data collected by satellites in polar orbit.
....
Delays in launching NOAA's new weather satellites have stemmed from administrative mismanagement and inadequate budgets, according to a watchdog agency.
....
Member Since: Posts: Comments:
spiderman duh
Member Since: Posts: Comments:
Quoting aspectre:
Remind you of anyone?


you? ;)

idk
Member Since: February 11, 2012 Posts: 0 Comments: 9725
Remind you of anyone?
Member Since: Posts: Comments:
hey guys just popping in to say that: there seem to be a surface low level circulation forming in the extreme SE caribbean, this is according to surface obs, ASCAT, and vort map at 850 and 925mb. there is convection in the area and in the upper levels, there is a upper level anticyclone in the area causing 10-20kt of shear and it is dropping. so I am just noting that and its just something to keep one eye on. hey maybe its EX-97L trying to make a comeback but this is all I am sayin
Member Since: Posts: Comments:
Half our neighborhood is at the beach right now, beginning the holiday early. And I commented to neighbor across the street as they prepared to leave for Wrightsville beach that they picked a good weekend to leave town because of the heat.

Hope everyone will be taking shelter in time.
Member Since: Posts: Comments:
Quoting TropicalAnalystwx13:

Yes it was. July 1, 1867.


no they formed canada then, but they werent independent
Member Since: February 11, 2012 Posts: 0 Comments: 9725
This is the N.C. seabreeze zoom..NSSL WRF 4 km grid initialized 00 UTC Jul 01 2012

36 h Total Precipitation (mm) (C-BRZ North zoom)
Member Since: Posts: Comments:
Quoting presslord:
there are TONS of people in small craft on open water along our coast this weekend

Well it looks like they couldn't break the cap and spread. So big rain but not tsunamis from sky, hopefully...?
Member Since: Posts: Comments:
GOES Imager Cloud Top Pressure
July 01, 2012 - 20:45 UTCGOES Imager Spectral Difference
July 01, 2012 - 20:45 UTC
Member Since: Posts: Comments:
Quoting KEEPEROFTHEGATE:
well they best head in or clear out of the way

There's a ton of people on Folly Beach right now.
Link Folly Beach Cam
Member Since: Posts: Comments:
Wind..lightening..no rain but good gracious it turned awful here real quick! I will talk to you guys later..
Member Since: August 19, 2006 Posts: 13 Comments: 15137
Member Since: Posts: Comments:
933. beell
oops
Member Since: Posts: Comments:
Quoting KEEPEROFTHEGATE:


lets get ready to rumble
Those look super-cellular..Hope they do not get beat up to bad.
Member Since: Posts: Comments:
Quoting presslord:
there are TONS of people in small craft on open water along our coast this weekend
well they best head in or clear out of the way
Member Since: Posts: Comments:
930. MZT
Quoting Tribucanes:
These heights in the Carolina's are insane. Thank goodness these beasts are headed to sea soon. Hope no one in small craft on open waters.
The beaches are probably full though, people taking time off before the July 4 holiday. Fortunately this is not a hurricane, with storm surge to worry about. But it'll be quite the show for folks on the OBX watching this roll over.
Member Since: Posts: Comments:
Link TopSail Island Web Cam

We may get a good view of storms over water from this cam.
Member Since: Posts: Comments:
there are TONS of people in small craft on open water along our coast this weekend
Member Since: Posts: Comments:
Quoting washingtonian115:
Well after staying over at my sisters house the power has been restored for me!!.I'm currently at my house with sweet,sweet A/C!.Some neighbors of ours still don't have power.Trees are still down in some places and street lights are out.Parts of Virginia and Maryland along with D.C still don't have any power and it could take up to a week or more :(.


I got my power back around noon and I'm so glad. I know all the tricks to stay cool but triple digits is too much for my little house for more than a day without AC.

Here's a description of my experience if anyone is curious.

This storm was sure different. It sounded different than any that I've been through (Hurricane Irene or Isabel). There was lots of air moving for a couple hours before it arrived. Then when the main event came (while watching the radar here), it was a very sudden change. It got my pets all jumpy especially when things began cracking and snapping--in addition to thunder and lightening. Then the power went and so did it. It seems like the whole thing lasted maybe 25 minutes or so.

The next morning there was a great deal of leaf little and small twigs/branches all over my neighborhood just the same as if a TS had blown through for a day.
Member Since: Posts: Comments:
These nasty storms are heading for Wilmington.

I'm out for now. Stay safe.
Member Since: Posts: Comments:
925. beell
Quoting beell:


5.5°C per kilometer (or 1,000 meters if you prefer) is a good general number for a saturated parcel


So...if you refer back to the sounding, the LCL or Lifted Condensation Level is about 1,000 meters. By theory, the LCL is where the parcel is saturated. The LFC is near 1400 meters. Pretty close together.

Check the various lapse rates at the bottom left of the sounding. All are greater than the MALR. I'd say there is a good chance of thunderstorms. But no cap to convection here.
;-)
Member Since: Posts: Comments:
These heights in the Carolina's are insane. Thank goodness these beasts are headed to sea soon. Hope no one in small craft on open waters.
Member Since: April 18, 2012 Posts: 0 Comments: 2437
Member Since: Posts: Comments:
Extremely heavy rain... wet hail... strong winds likely based on this.
Member Since: Posts: Comments:
Quoting Unfriendly:


WOW what in the sick nasty is that product?

GR2AE (GR2Analyst).
Member Since: Posts: Comments:
Several of my friends are saying there are funnel clouds. All I can see is an amazing looking shelf cloud.
Member Since: July 6, 2010 Posts: 113 Comments: 31895
ncstorm about to take a direct hit in NC near Jacksonville, praying for him it looks bad.
Member Since: April 18, 2012 Posts: 0 Comments: 2437
Quoting WxTracker15:


WOW what in the sick nasty is that product?
Member Since: Posts: Comments:
Quoting wilmingtonistoast:
Can we please get an Invest on the former Ms. Senegal at 10 west? She looks solid, with 3 days of favorable conditions in front of her.

Avila and the guys are at the beach today?


Maybe The models aren't showing anything. Link Experimental Forecast Tropical Cyclone Genesis Potential Fields
Member Since: Posts: Comments:
Member Since: Posts: Comments:
Quoting KEEPEROFTHEGATE:


lets get ready to rumble

Maybe that line can make it over water before what goes up must come down..
Member Since: Posts: Comments:
914. beell
Quoting weatherh98:


by moist laps rate do you mean wet adiabatic lapse rate? i think that 6.8 degrees per 1000 meters


5.5°C per kilometer (or 1,000 meters if you prefer) is a good general number for a saturated parcel
Member Since: Posts: Comments:
Quoting VAbeachhurricanes:
Does the MCS in Indiana moving into Ohio have a chance to be a Derecho all the way into VA again?


CWG mentioned it on a update posted to Facebook that they are watching it, it has a chance but won't be as bad as Fridays
Member Since: Posts: Comments:
Quoting Chucktown:


We're here for ya Press. Impressive instability just to our north and west. Tops near Florence are between 60 and 70 K feet. Still haven't busted the cap yet, but a special 18 Z sounding was done at CHS and CAPE and LI's are off the charts. Its going to take another hour or two to break the cap, but once we do, things are going to blossom rather quickly. Also, the seabreeze is pretty pinned to the coast this afternoon, just another added factor to the impending convection. The developing MCS will probably effect us here in the tricounty around 7 PM.


Here is the link to the soundings, including the 18z that was run....

Link
Member Since: Posts: Comments:
Quoting TropicalAnalystwx13:
So the power's flickering here and the storms haven't reached us yet?


your not gonna have power
Member Since: June 17, 2011 Posts: 11 Comments: 6469
Member Since: Posts: Comments:
V4 62 dBZ 62,000 ft. 98 kg/m²

wowza.
Member Since: Posts: Comments:
So the power's flickering here and the storms haven't reached us yet?
Member Since: July 6, 2010 Posts: 113 Comments: 31895
Quoting VAbeachhurricanes:
Does the MCS in Indiana moving into Ohio have a chance to be a Derecho all the way into VA again?


prolly not this is 15 hours of the 12z run
Member Since: June 17, 2011 Posts: 11 Comments: 6469


lets get ready to rumble
Member Since: Posts: Comments:
Can we please get an Invest on the former Ms. Senegal at 10 west? She looks solid, with 3 days of favorable conditions in front of her.

Avila and the guys are at the beach today?
Member Since: Posts: Comments:

Viewing: 955 - 905

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25Blog Index

Top of Page

About

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

Local Weather

Overcast
71 °F
Overcast