Another wild night in Tornado Alley

By: Dr. Jeff Masters , 11:40 AM GMT on May 06, 2007

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The sirens sounded two more times in tornado-ravaged Greensburg, Kansas last night, as two more twisters tore through the county. However, both tornadoes missed populated areas, as did most of the approximately 75 tornadoes that touched down yesterday. The action should quiet down considerably today; the Storm Prediction Center (SPC) has placed most of Kansas and Nebraska under its "Slight Risk" area for severe weather. Sweetwater, Oklahoma received significant damage from a tornado last night, and we've saved 300 Kb animations of the radar reflectivity and Doppler velocities of the tornado.

It will take a long time for Greensburg to recover from Friday's tornado. To get an idea of the scale of devastation, see the aerial photos posted by the Wichita Eagle. Damage surveys are not yet complete on the tornado, but photos I've seen of the destruction show damage consistent with EF4 winds(168-199 mph). It is possible the storm was an EF5 (winds more than 200 mph). The nine deaths from the tornado bring the U.S. tornado death toll to 68 so far this year, two more than the toll for all of last year.

We've saved some extraordinary 1 Mb animations of the radar reflectivity and Doppler velocities of the tornado. I asked wunderground meteorologist and tornado expert Rob Carver to comment on what's going on in the animations, and here was his analysis:

This was likely an example of cyclic mesocyclogenesis. In a nutshell, the rear-flank downdraft surges out, wraps around and occludes the mesocyclone (Meso A for short). Meso A then veers to the left and dies, this is why tornado family members curve to the left as they dissipate. While Meso A is dying, a new meso spins up and becomes the dominant meso. Now, while I've seen plenty of simulated cyclic cases where the hook retreats when Meso A occludes, I don't think I've seen anything as dramatic.



Figure 1. Radar image of the storm that spawned the Greensburg, KS tornado of May 4, 2007, showing the clearly defined hook echo associated with the twister.

Coastal Carolina storm
The latest (8pm EDT) computer forecast models continue to show a moderately strong coastal storm developing several hundred miles southeast of Cape Hatteras, North Carolina, on Monday. The storm will be extratropical in nature when it forms. We'll have a lot of time to watch the storm, as it is expected to meander offshore for five days and gradually weaken. Water temperatures are 22-23 C off of the coast, which may be warm enough to allow the low to acquire some subtropical characteristics and become the season's first named storm. The models are hinting that the storm could remain over water long enough for this to happen, and I put the odds of a Subtropical Storm Andrea forming late this week at about 20%.

Wunderblogger Mike Theiss was out chasing yesterday and caught some of the storms; be sure to tune into his blog over the next few days to read his chase accounts. Stormchaser Dan Robinson posted some video stills of the Greensburg tornado.

Jeff Masters

()
Storm Brewing (thomasanthony)
A big storm moved in on the 3rd. Wasn't as bad as it looked though.
Storm Brewing

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634. Patrap
7:10 PM CDT on May 06, 2007
Im all Jazz Fested out...LOL. OLd Links today.
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633. StormJunkie
12:08 AM GMT on May 07, 2007
Good link pat! Thanks ☺

It can now also be found here. Thanks to you!
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631. HurricaneFCast
12:05 AM GMT on May 07, 2007
Weatherguy03- Haha. Yeah, i'm sure i'll need it. I do try not to attack anyone personally, though. That's not what i seek. I seek correct information and high probability in predictions. I want the vast degree of views that are on the blog. It helps you to think of every possible thing before making your own prediction.
Member Since: April 20, 2007 Posts: 7 Comments: 1482
630. Patrap
7:07 PM CDT on May 06, 2007
NHC Model Overview...Link
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629. GetReal
12:00 AM GMT on May 07, 2007
Posted By: MichaelSTL at 11:55 PM GMT on May 06, 2007.

Early storms are also not really exceptional; 1992 and 1997 both had a subtropical storm in May and 2003 had a tropical storm in April so we are probably due for another early storm (most likely subtropical, tropical si also possible but the chances of a hurricane are probably low, much less one like Able).

Yes MichaelSTL I do agree with you, but in 1992,1997, and 2003 we did not have a volitale oil futures market to contend with!!! The price of a barrel of oil in the 1990's was around $17 to $30 a barrel...

Any early named activity would drive the speculators wild, can you say $85 to $90 a barrel, or higher!
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626. MTJax
12:03 AM GMT on May 07, 2007
HFC, ST is someone who frequents the blog. Good guy, lots of fun. I'm relly not picking on you so dont take it that way. Its more a nudge to get ST to show up.

BTW...surface low, crosses central FL to the gulf mid week and brings about 1" of the much needed rain.
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625. HurricaneFCast
12:03 AM GMT on May 07, 2007
JUSTCOASTING- I see a Tornado Warning in Collier and Broward. That's it. I think you're safe.
Member Since: April 20, 2007 Posts: 7 Comments: 1482
624. ryang
8:04 PM AST on May 06, 2007
You guys could come to my blog....if you want!!!!
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623. weatherguy03
8:04 PM EDT on May 06, 2007
Ahhh HFCast, looks like you will make some friends on here this season..LOL Good luck:)
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622. HurricaneFCast
12:01 AM GMT on May 07, 2007
Hurricaneman23- Sorry for the delay in the response to your post.. I believe no one can answer that question confidently at the moment. It seems that it would move Southwest, but how far? We don't know. Most of the models to develop it but they do not have a clear consensus on possible direction or any possible landfalls.
Member Since: April 20, 2007 Posts: 7 Comments: 1482
621. JUSTCOASTING
11:59 PM GMT on May 06, 2007
any one hear of a tornado on the ground in sw florida glades county ?
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620. HurricaneFCast
11:58 PM GMT on May 06, 2007
MTJax.. Honestly.. I don't know who the hell you're talking about. I'm being honest. If you don't believe me, so be it. I don't care. I'm here to discuss the weather, I'm a future meteorologist and i'm working towards my degree right now.. I love the tropics. I'm also new to the site. I tried it at the end of last H season and loved the blogs. It's great to be able to have instant updates here and other intellectuals with knowledge of the weather. We can all learn here, it's a good place to go. I just became a premium member for the $10 a year or w/e earlier this month and i will frequent the blog this summer.
Member Since: April 20, 2007 Posts: 7 Comments: 1482
619. Drakoen
12:00 AM GMT on May 07, 2007
i'll have to go guys i'll see you tommorrow
Member Since: October 28, 2006 Posts: 57 Comments: 30562
618. weatherguy03
7:59 PM EDT on May 06, 2007
HFCast. Yes, I know alittle something about that..LOL You didnt offend me, again we are having fun.
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617. Bamatracker
11:59 PM GMT on May 06, 2007
you tell 'em hellsniper!!
Member Since: May 17, 2006 Posts: 6 Comments: 1367
616. ryang
7:58 PM AST on May 06, 2007
8:00pm outlook...Link
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614. Hellsniper223
11:57 PM GMT on May 06, 2007
Okay.. Why in god's name does it matter to y'all that it's subtropical or tropical? It's only a bloody structural difference. Same damned storm. lol
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613. franck
11:57 PM GMT on May 06, 2007
Well, shear conditions have turned somewhat favorable for development off the SE coast.
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612. Patrap
6:58 PM CDT on May 06, 2007
8
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611. ryang
7:56 PM AST on May 06, 2007
Surface map....NHC says developing low...LOL

Link
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610. HurricaneFCast
11:54 PM GMT on May 06, 2007
Weatherguy03- No clue who you're talking about... But when whether is your career path, it means something to you. So i'm sorry if i offended you. I don't want any animosity, we're just arguing.. people do that and it's good too, you need different perspectives on every situation, it brings a wealth of information to the table.
Member Since: April 20, 2007 Posts: 7 Comments: 1482
609. hurricaneman23
11:53 PM GMT on May 06, 2007
hurricanefcast if it is a ts, where do u think it will go?
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608. MTJax
11:56 PM GMT on May 06, 2007
HFC is ST in disguise. Also, my bet is 1008-1007 by Thursday, no better than that.
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607. Tazmanian
4:55 PM PDT on May 06, 2007
Posted By: Bamatracker at 4:54 PM PDT on May 06, 2007.

the odds are 10-1...place your bets.
Posted By: ryang at 4:54 PM PDT on May 06, 2007.

Navy Site...Link
Posted By: jphurricane2006 at 4:54 PM PDT on May 06, 2007.

can it be a subtropical depression 03? I believe there is such a thing, right? lol
Posted By: Drakoen at 4:54 PM PDT on May 06, 2007.


Can i have the navy site link please.
Posted By: Tazmanian at 4:54 PM PDT on May 06, 2007.

navy site

Link



lol 5 post are all at the same time
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606. Drakoen
11:54 PM GMT on May 06, 2007
lol MT i didn't realize that you put "j/k" next to your post lol. At least i ahve it now for future reference.
Member Since: October 28, 2006 Posts: 57 Comments: 30562
605. ryang
7:54 PM AST on May 06, 2007
Drakoen i justed posted the NHC 8:00PM outlook...LOL
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604. weatherguy03
7:55 PM EDT on May 06, 2007
Yes it can JP. Oh Drakoen, you didnt offend me. I am just having some fun. You can have your opinion, thats what makes all of this fun.
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603. melwerle
11:53 PM GMT on May 06, 2007
Thank you JP!
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601. Bamatracker
11:53 PM GMT on May 06, 2007
the odds are 10-1...place your bets.
Member Since: May 17, 2006 Posts: 6 Comments: 1367
600. ryang
7:52 PM AST on May 06, 2007
Navy Site...Link
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598. Drakoen
11:52 PM GMT on May 06, 2007
Posted By: weatherguy03 at 11:49 PM GMT on May 06, 2007.

Drakoen..LOL Ok I guess you haven't read my bio. Love ya too!


lol ok let me restate that and say i would love to hear what the people at the NHC say. Sorry if i offended you position. Guess we have to disagree to agree. I think it will be a warm core as it already is.

Can i have the navy site link please.
Member Since: October 28, 2006 Posts: 57 Comments: 30562
597. Tazmanian
4:53 PM PDT on May 06, 2007
navy site

Link
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596. weatherguy03
7:52 PM EDT on May 06, 2007
HFcast. Are you related to Stormtop!!..LOL Its ok, its only weather.
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595. hurricaneman23
11:51 PM GMT on May 06, 2007
what are the odds of a td1 forming with this?
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593. melwerle
11:51 PM GMT on May 06, 2007
can someone please send me a link to the navy site so i can save it?
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592. GetReal
11:48 PM GMT on May 06, 2007
Yeah Bob you can call it a conspiracy if yoy like, but at the end of season review they will come back and declare this an unnamed system!!! NHC M.O.
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591. HurricaneFCast
11:44 PM GMT on May 06, 2007
I'm tellin' ya'll right now. Watch this thing. It will develop. Weatherguy.. Let's go fundamental... The big blob of green = 26.6-27C= 79.8-80.8F, Go further south to the yellow, it reaches towards the 82F mark. These temperatures are high enough to support a TROPICAL STORM. We are not talking about a hurricane people. This thing could be a Tropical Storm AT BEST. That's all i've ever been saying. I never said the word Hurricane. Also, don't take the 80 Degree mark as a milestone. It doesn't have to be 80 degree water for a storm to form, especially with high moisture content in mid-latitude and upper-latitude layers in addition to low vertical wind shear. All which is present and/or will be present for the duration of this thing. I believe it will form, but it will weaken before it makes landfall, if it does at all. The argument we've been having is about the formation of a TS, not a hurricane, and not about where it will go. It will be a Tropical Storm if it forms, the conditions are there. The environment is so unstable it's not even funny.. i mean.. there's tornados in florida... and there have been over 10,000 lightning strikes in the past 8 hours in Florida. The atmosphere is highly unstable and conducive for tropical development. Anyways, I don't need my blood pressure any higher.. lol. So i'm gonna calm down now. Sorry if I sounded angry in this post, i'm just very passionate about my beliefs.
Member Since: April 20, 2007 Posts: 7 Comments: 1482
590. Tazmanian
4:50 PM PDT on May 06, 2007
so where is 90L are they going to put it up on the navy site or not?
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589. weatherguy03
7:50 PM EDT on May 06, 2007
JP, I am used to it...LOL Everyone likes to do that to me, I can take it:)
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588. weatherguy03
7:49 PM EDT on May 06, 2007
BTW Drakoen. I never said it would be a cold core. Subtropical. Listen..LOL
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586. weatherguy03
7:48 PM EDT on May 06, 2007
Drakoen..LOL Ok I guess you haven't read my bio. Love ya too!
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585. ryang
7:48 PM AST on May 06, 2007
THE BIG STORY IS ASSOCIATED WITH A STRENGTHENING LOW PRES SYSTEM
OFF THE CAROLINA COASTLINE....ANALYZED 1009 MB NEAR 35N74W. A
BACK DOOR COLD FRONT IS PROGRESSING SWD FROM THE LOW TO NE
FLORIDA. THIS LOW HAS AN IMPRESSIVE LARGE CIRCULATION WITH
MULTIPLE BOUNDARIES ROTATING AROUND IT PRODUCING SCATTERED
SHOWERS N OF 28N W OF 70W.
THE MAIN IMPACT IS THE STRONG WINDS
AS A VERY TIGHT PRES GRADIENT HAS SET UP BETWEEN THE LOW AND
STRONG HIGH PRES OVER THE ERN GREAT LAKES. SHIPS/BUOYS ARE
REPORTING NLY WINDS TO 40 KT NOT FAR OFF THE SE COAST. GLOBAL
MODELS ARE NOW IN PRETTY GOOD AGREEMENT SHOWING THE SYSTEM
STRENGTHENING FURTHER AS IT TAKES A LOOPING OR SLOW WWD MOTION
TOWARD THE SE COAST. SEVERAL MODELS ARE ALSO SHOWING THE SYSTEM
BECOMING LESS FRONTAL IN NATURE OVER THE NEXT COUPLE DAYS.
MARINE IMPACTS ARE EXPECTED TO BE SIGNIFICANT IN THE NW PORTION
OF THE AREA...REFER TO MIAHSFAT2 FOR DETAILS S OF 31N. FARTHER
E...A WEAK 1011 MB LOW LOCATED NEAR 28N61W IS PRODUCING
SCATTERED SHOWER ACTIVITY NE OF THE LOW FROM 26N-31N BETWEEN
55W-57W. A SFC TROUGH HANGS S/SW FROM THE LOW TOWARD THE NRN
COAST OF HISPANIOLA...DEFINED BY A WIND SHIFT.

8:00pm NHC update...
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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.