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 much time to do TCRs tonight, but I did update (but not complete -- technically I haven't completed any of them, because I have yet to add six hour position and intensity estimates, which I will do later :P) Chris's. Here is section b:

b. Meteorological Statistics

Observations in Hurricane Chris include satellite-derived intensity estimates based on the Dvorak technique, surface wind estimates of NOAA's Advanced Scatterometer (ASCAT), vertical temperature profiles courtesy of the Advanced Microwave Sounding Unit (AMSU), and SSMIS microwave data (not shown).

Chris's peak intensity of 65 kt is based solely on satellite images, which showed a well-defined eye embedded within a circular mass of relatively deep convection. It should be noted that although the eye appeared for about six hours prior to the time Chris is assumed to have become a hurricane, corresponding Dvorak numbers, both subjective and objective, did not reflect hurricane intensity until about around 1300 UTC, an approximate hour after Chris became a hurricane. Around 0600 UTC, when the eye first became evident, the reported status of the cloud pattern was that of curved banding. It is a little unclear as to why this was the case. Perhaps Dvorak rules do not work as well with high latitude systems over cool waters, particularly with systems that are strengthening.

There have been no ship reports of tropical storm force winds or greater with Chris. However, as Chris was moving to the north of Bermuda on 17 June, Saint David's on the northern end of the island reported wind gusts as high as 45 kt. These winds caused little damage, and were quite brief.
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We finally got to a new page and now all looks good with the blog format/display again. I agree a different browser may not experience what several of us did. However, going to a new page changed something at the source. There is a SW bug that likely will be to complicated to spend the money to figure out. Back to the tropics for me, however that will be in the morning. Nite all, and thanks again.
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The issue is a conflict between the IE code and the video encoding... exactly what I'm not sure, but I've only ever had problems with video posts. And not all of them, either.The only blogger I ever put on my ignore list is somebody who keeps posting utube videos with this disruptive code.
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Quoting MelbourneTom:


The Company knows and will be changing soon. It has worked well over the years and has avoided many security issues refered to because it was not porular enough to be a target.



ok good i would give google chrome or firefox a try and see wish one would be better but i think google chrome will be the better one too go with has some time firefox can have a lot of bugs stills too be worked out
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Quoting RTSplayer:


Has that been confirmed by human observers?

I didn't trust the radar estimates because in the past the radar nearly doubles it's estimates of extreme precipitation events.

Corpus Radar says over a foot, and Brownsville radar says over 10 inches in that area, but what does an actual rain gauge say?


In central Florida its often the opposite, rainfall is often double the estimate :)

The NWS was very good with later creating a revised radar estimate for tropical storm Debby that was spot on accurate from what I could see, however the initial estimate on the radar image was utter fail, showing rain totals of 2 to 4 inches over the Tampa Bay area when actual totals were 8 to 15 inches, lol...
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Quoting Tazmanian:



i hop you no that Netscape been discontinued


The Company knows and will be changing soon. It has worked well over the years and has avoided many security issues refered to because it was not porular enough to be a target.
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Quoting AussieStorm:
Is anyone having problems with FF and viewing satellite loops? I get a crazy long error when I try to view loop or even a embedded video.




nop not me i swich too google chrome 20 and it is a lot better then firefox
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Quoting MelbourneTom:


Before I retired, 2 weeks ago, I also saw this type of blog error on Netscape which I had at work. It's something more than just IE.



i hop you no that Netscape been discontinued
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Mosquitoes in most parts of the country are at very minimal levels due to heat and lack of rain. But parts of Florida are dealing with the buggers no doubt. Maine has em too bad. There's are way to big to be mosquitoes. Live fifty yards from a river here in Wisconsin and they have been non-existent. I'd take the rain and cooler temps. any day.
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Is anyone having problems with FF and viewing satellite loops? I get a crazy long error when I try to view loop or even a embedded video.
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Quoting STXHurricanes2012:
So no cares about the near 13 inches near falcon dam....it caused the main highway to close due to high water!!!


At least falcon lake will stay full.
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Quoting JLPR2:
Ah yes, IE, you people still use that? XD
Nah, just kidding, if you like it, go ahead.

But yep, using Chrome and the blog seems fine to me.



yep am uesing chrome 20 and the blog is find for me
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493. JLPR2
Quoting BahaHurican:
Hey, Grothar. Looks like the dry air got to it first... 97L is currently a thin line of spotty shower activity crossing through the Lesser Antilles tonight. Our PR bloggers are hoping for some rain.


You can say that again, I'm crossing my fingers for a few lengthy showers from this TW.
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492. JLPR2
Ah yes, IE, you people still use that? XD
Nah, just kidding, if you like it, go ahead.

But yep, using Chrome and the blog seems fine to me.
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Quoting sunlinepr:


The problem with that browser is that hackers are constantly making holes in that old code... (its one of the oldest codes around)... it's very vulnerable... computer 3rd graders in China are shown how to make holes in the source code... their goal? to steal drones in the air... ;)


Before I retired, 2 weeks ago, I also saw this type of blog error on Netscape which I had at work. It's something more than just IE.
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Mosquitoes have been atrocious here lately.
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We got heavy rain early this morning and it threatened most of the day but we haven't had any since about 30 minutes ago. When I say we, I mean at my house. I believe it has been scattered showers throughout the area.
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Will it be a strong El Nemo?
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Quoting AllBoardedUp:
AtHomeInTx, where are you located? I'm in Hitchcock. Just had a small shower come in from the gulf.


In Vidor/Orange Co. Been raining here on and off all day. Lightning sparked an oil tank fire in Sour Lake earlier too.
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Quoting Tazmanian:
EL NINO is likey going too kick in by mid too late july so hurricane season may be overe by time AUG gets here and for sure SEP will likey see no name storms at all


Taz, it would take a miracle for us not to see any development in September. Even in 1997 we had a major hurricane that month (Erika).

More likely, the season will be compact, in that the majority of activity will occur in Aug/Sep, with an abrupt shut down after that.
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Quoting AussieStorm:

Have you tried hiding the post, are you using the old format or the new format. I use the old format and have no problems. I use Chrome and FF but with FF I can't view satellite loops so I transferred all my links over to chrome.
Classic version of WU


Aussie, thanks this works much better.
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Quoting MelbourneTom:
479 sunlinerp
Thanks, I have stored it, will look into it tomorrow.


The problem with that browser is that hackers are constantly making holes in that old code... (its one of the oldest codes around)... it's very vulnerable... computer 3rd graders in China are shown how to make holes in the source code... their goal? to steal drones in the air... ;)
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Quoting aislinnpaps:
I don't know if it was just me, but that video messed up the blog. :(

Have you tried hiding the post, are you using the old format or the new format. I use the old format and have no problems. I use Chrome and FF but with FF I can't view satellite loops so I transferred all my links over to chrome.
Classic version of WU
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479 sunlinerp
Thanks, I have stored it, will look into it tomorrow.
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AtHomeInTx, where are you located? I'm in Hitchcock. Just had a small shower come in from the gulf.
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Getting some unexpected weather around here. From our little friend in the gulf.





Morning's storms spawns isolated tornado



The scattered showers and storms from Saturday morning spawned off a tornado a 12 News HD viewer captured on camera in the southern Cameron Parish area.

No damages and no injuries were reported.

NATIONAL WEATHER SERVICE LAKE CHARLES LA
745 PM CDT SAT JUN 30 2012

.UPDATE...RADAR CURRENTLY SHOWING ANY SHOWER AND THUNDERSTORM
ACTIVITY INLAND HAS DISSIPATED OR EXITED OUT OF THE AREA. THIS
EVENINGS SOUNDING AT LCH SHOWING PWATS AT 2.00 INCHES...THIS WELL
ABOVE THAT PROJECTED BY MODELS. WITH LOW/TROF MEANDERING JUST TO
OUR WEST...INCREASED MOISTURE...AND NORTHWARD TRACKING
DISTURBANCES OVER THE WESTERN GULF...HAVE EXPANDED LOW END POPS
EASTWARD TO INCLUDE THE LAKE CHARLES AREA FOR TONIGHT.

&&
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Quoting MelbourneTom:
471 aislinnpaps
I agree, if it take to long I will see in the morning.

472 sunlinepr
Thaks but I can not read anything after "browser..."
This is why I am intersting Enter, CR LF, on my reply.
I have never used anything but IE from the begining
and these others are not installed on my machine. I
assume from your reply that you are nit seeing a
problem. Which browser do you use? Thanks.


I use Firefox Or You can use Chrome Avant Opera Comodo They are free Link
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What's everyone talking about? My computer seems to be working fine.
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Sorry, I get the fat finger of fate award on my last
post. It is still readable though.
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Okay who did it.......this does happen by accident couple times a year no doubt.
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471 aislinnpaps
I agree, if it take to long I will see in the morning.

472 sunlinepr
Thaks but I can not read anything after "browser..."
This is why I am intersting Enter, CR LF, on my reply.
I have never used anything but IE from the begining
and these others are not installed on my machine. I
assume from your reply that you are nit seeing a
problem. Which browser do you use? Thanks.
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Are we there yet?
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Random comment to get to the next page............please no more hot!
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Quoting MelbourneTom:
I tried closing and reopneing IE9 and I now have
rebotted. I can not get a proper blog display
since the derecho clips were posted. I am using
on this in hopes it will not be clipped. Does
anyone know how to correct this?


Use Chrome, Firefox, Opera, even Avant browser (uses IE engine) or any other browser.... I'm using Firefox...
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Can't quote, but mine was good until #459. I'm waiting until it goes to the next page and then the blog should work normal again.
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Hey Grothar, looked up the meaning of your name a long time ago. Told me what I already knew. :) Sorry for your health issues, doubt you've ever been a soft one though. Whole family's praying for ya. But if the dinosaurs didn't kill ya then I'm guessing your gonna be okay.
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I tried closing and reopneing IE9 and I now have
rebotted. I can not get a proper blog display
since the derecho clips were posted. I am using
on this in hopes it will not be clipped. Does
anyone know how to correct this?
Member Since: Posts: Comments:
Tropical wave still alive? On satellite it looks like a three armed W to let us know. Mexico and Texas getting some much needed rain, little bright light on a tough weather week for so many.
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EL NINO is likey going too kick in by mid too late july so hurricane season may be overe by time AUG gets here and for sure SEP will likey see no name storms at all
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I don't know if it was just me, but that video messed up the blog. :(
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Quoting Grothar:
Just woke up. Anything new? Did that big ULL knock out 97L?


How's things om your side of the world Gro?
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After running the derecho clips everything on the right is clipped. Looks like it has gone from being left justified to center justified. Anyelse experiencing this and if so how do I correct it?
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Quoting Grothar:
Just woke up. Anything new? Did that big ULL knock out 97L?
Hey, Grothar. Looks like the dry air got to it first... 97L is currently a thin line of spotty shower activity crossing through the Lesser Antilles tonight. Our PR bloggers are hoping for some rain.
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Recent video of unusual tornado in France.

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Quoting Chicklit:
They said they didn't know where the wave was at 8 p.m. so that may be it showing some convection at 11:30. Anyhow, everything is more understandable in the morning. By the way my friend in Washington DC suburb says she's been without power for 24 hrs.
Is this because of the derecho?
Very likely. Just about all our bloggers in the area lost power for a while. Dunno if DC115 has power back at her house yet.
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Quoting Patrap:


LOL..............pretty much covers things
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Just woke up. Anything new? Did that big ULL knock out 97L?
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the MJO is now in phase 2. Development shouldn't happen for a few weeks now...
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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.