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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434. RL3AO
5:12 PM CDT on May 06, 2007
Roman, where do you live in Broward County?
433. Drakoen
10:12 PM GMT on May 06, 2007
i'm am undecided whether or not the system has improved from the new satellite image

link
Member Since: October 28, 2006 Posts: 57 Comments: 30830
432. i12BNEi
10:10 PM GMT on May 06, 2007
Crystal Beach (North of Clearwater) is clear,But the storms are just getting to Pasco County.
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431. Bamatracker
10:10 PM GMT on May 06, 2007
Link

This is the quickest updated model page i know of.
Member Since: May 17, 2006 Posts: 6 Comments: 1367
429. lilmax
9:41 PM GMT on May 06, 2007
Tornado vortex signature storm moving into Broward!
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428. Drakoen
10:09 PM GMT on May 06, 2007
Posted By: Bamatracker at 10:03 PM GMT on May 06, 2007.

evening jp! 18 utc GFS dissipates teh system over water starting at 72 hrs out.


link please
Member Since: October 28, 2006 Posts: 57 Comments: 30830
427. chessrascal
10:05 PM GMT on May 06, 2007
im in sarasota not a cloud in the sky
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426. RL3AO
5:08 PM CDT on May 06, 2007
Thats for determining rotation. Green is wind blowing towards the radar, browns are wind blowing away from radar.
425. HurricaneRoman
10:06 PM GMT on May 06, 2007
umm how do u read that map and what is it for?
Member Since: February 25, 2006 Posts: 2 Comments: 959
424. RL3AO
5:04 PM CDT on May 06, 2007
removed out of date pic
423. JUSTCOASTING
10:03 PM GMT on May 06, 2007
I am here in Punta Gorda fla still have sunny skys on the west coast
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422. HurricaneRoman
9:58 PM GMT on May 06, 2007
they upgraded it to a tornado warning..... =/ ...i hope it loses some of its energy b4 it arrives here
Member Since: February 25, 2006 Posts: 2 Comments: 959
421. Bamatracker
10:02 PM GMT on May 06, 2007
evening jp! 18 utc GFS dissipates teh system over water starting at 72 hrs out.
Member Since: May 17, 2006 Posts: 6 Comments: 1367
420. franck
9:54 PM GMT on May 06, 2007
Yep, it is amazing how big oil speculation is rampant, and not a single representtive of the government is willing to say a word about it. Most of them say there is nothing which can be done, which is like issuing a license to kill to futures speculators.
The world is stacked with oil reserves, but speculators keep driving the price higher in spite of it. But they can't get burned because the government is supporting the speculation by constantly buying up for the 'strategic oil reserve.' Gasoline will hit $5/ gallon soon.
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419. hurricaneman23
10:00 PM GMT on May 06, 2007
i live in west pembroke pines, looks like its heading south towards me
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417. RL3AO
4:58 PM CDT on May 06, 2007
I dont like the look of the cell near Boca Raton.
416. Bamatracker
9:57 PM GMT on May 06, 2007
new gfs is coming out
Member Since: May 17, 2006 Posts: 6 Comments: 1367
415. HurricaneRoman
9:56 PM GMT on May 06, 2007
hmm well there is a really strong severe storm on the broward/palm beach county line and im sure some ppl on here live there.... i wonder if this storm will hold its strength by the time it gets to my area(south broward)
Member Since: February 25, 2006 Posts: 2 Comments: 959
414. Bamatracker
9:54 PM GMT on May 06, 2007
either dinner or all the Floridians lost power
Member Since: May 17, 2006 Posts: 6 Comments: 1367
413. RL3AO
4:54 PM CDT on May 06, 2007
I guess everyone went for dinner.
412. Drakoen
9:53 PM GMT on May 06, 2007
did everyone leave?
Member Since: October 28, 2006 Posts: 57 Comments: 30830
411. Drakoen
9:48 PM GMT on May 06, 2007
hurricane23 i am talking about this

link
Member Since: October 28, 2006 Posts: 57 Comments: 30830
410. HurricaneRoman
9:45 PM GMT on May 06, 2007
omg i bet it wont rain here in south Broward!! My grass is so dry and some of it looks dead already... I havent seen a good shower in at least a couple months
Member Since: February 25, 2006 Posts: 2 Comments: 959
409. Drakoen
9:43 PM GMT on May 06, 2007
Posted By: hurricane23 at 9:40 PM GMT on May 06, 2007.

Nothing is organized of the florida coast as you can see on this radar image.


not of the Florida coast i am talking about the low of the North Carolina Virginia Coast.
Member Since: October 28, 2006 Posts: 57 Comments: 30830
408. Drakoen
9:43 PM GMT on May 06, 2007
few images that might interest you i don't know how current they are though...

24hr forecast:
link


link

link
Member Since: October 28, 2006 Posts: 57 Comments: 30830
407. chessrascal
9:41 PM GMT on May 06, 2007
im in Sarasota Florida and there is not a cloud in the sky
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406. lilmax
9:32 PM GMT on May 06, 2007
I'm quite concerned about that C1 storm that triggered the Severe Thunderstorm Warning for Broward county. It doesn't seem to want to die out.
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405. hurricane23
17:35 EDT le 06 mai 2007
Nothing is organized of the florida coast as you can see on this radar image.

Free Image Hosting at www.ImageShack.us

Overall i think it has a chance to be sub-tropical storm by mid-week. But probably not a tropical storm or hurricane. SST's are too cold, upper-level shear will be high and it may moving inland before it ever gets a chance.

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404. weathersp
5:37 PM EDT on May 06, 2007
The new 18z WRF/NAM shows the system comeing onshore at Charlson,SC.
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403. GetReal
9:38 PM GMT on May 06, 2007
Drakoen it is not only the media... The biggest concern is the oil future prices pushed up by speculators hoping for a active season!!!
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402. chessrascal
9:38 PM GMT on May 06, 2007
would someone post a link or picture of this my computers having trouble. http://www.wunderground.com/satellite/vis/1k/US.html
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401. southbeachdude
9:34 PM GMT on May 06, 2007
no rain in Miami yet :-(
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400. Drakoen
9:36 PM GMT on May 06, 2007
Posted By: GetReal at 9:35 PM GMT on May 06, 2007.

Drakoen they (NWS) will cover their respective rear ends by issuing the gale warnings, small craft warnings and etc


yea i don't think they would hold back that type of information just because of the Media.
Member Since: October 28, 2006 Posts: 57 Comments: 30830
399. Bamatracker
9:33 PM GMT on May 06, 2007
evening SJ...how ya doing tonight?
Member Since: May 17, 2006 Posts: 6 Comments: 1367
398. GetReal
9:33 PM GMT on May 06, 2007
Drakoen they (NWS) will cover their respective rear ends by issuing the gale warnings, small craft warnings and etc...
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397. Drakoen
9:34 PM GMT on May 06, 2007
Hurricane23 i wanna know your thought about the Low pressure system of the coast. Whats your predicition?
Member Since: October 28, 2006 Posts: 57 Comments: 30830
396. Drakoen
9:32 PM GMT on May 06, 2007
Posted By: hurricane23 at 9:31 PM GMT on May 06, 2007.

Everything is pushing to the south...

Its going to nail me later.


Yea i am in central Palm Beach county just waiting for the action to come light to moderate rain now with that cell.
Member Since: October 28, 2006 Posts: 57 Comments: 30830
395. weathersp
5:32 PM EDT on May 06, 2007
I swear there is a tornado just SW of Medicine Lodge,KS
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394. Drakoen
9:31 PM GMT on May 06, 2007
Posted By: StormJunkie at 9:30 PM GMT on May 06, 2007.

Reclass at the end of the year again GR? lol

Mel, this is going to be just kinda of hanging around for several days, and when that happens it is very hard to forecast track IMHO>


Yes but the models have a generel agreement of the system making "landfall" somewhere along the south East coast of the United States.
Member Since: October 28, 2006 Posts: 57 Comments: 30830
393. GetReal
9:31 PM GMT on May 06, 2007
Sj that is exactly my thinking on how NHC will handle it...
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391. hurricane23
17:31 EDT le 06 mai 2007
Everything is pushing to the south...

Its going to nail me later.

Free Image Hosting at www.ImageShack.us
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390. Drakoen
9:29 PM GMT on May 06, 2007
Posted By: GetReal at 9:29 PM GMT on May 06, 2007.

I do not believe that the NHC will name this system as a sub-tropical, or tropical storm, due to political and economic considerations. The NHC probably will not want to fan the media hype of an early and very active season starting this early.
Its funny because we are talking about the low alot and its not even an invest.

lol that wouldn't be right especially if this system does become tropical. Screw the media. It is important for people to know about events such as these.
Member Since: October 28, 2006 Posts: 57 Comments: 30830
389. StormJunkie
9:29 PM GMT on May 06, 2007
Reclass at the end of the year again GR? lol

Mel, this is going to be just kinda of hanging around for several days, and when that happens it is very hard to forecast track IMHO>
Member Since: August 17, 2005 Posts: 26 Comments: 16874
387. RL3AO
4:29 PM CDT on May 06, 2007
Posted By: GetReal at 4:29 PM CDT on May 06, 2007.
I do not believe that the NHC will name this system as a sub-tropical, or tropical storm, due to political and economic considerations. The NHC probably will not want to fan the media hype of an early and very active season starting this early.


Plus an early season storm doesnt help oil prices any, even if it gets no where near the GOM.
386. Drakoen
9:28 PM GMT on May 06, 2007
I am waiting to see if the system gets strong thunderstorms wrapping around its center. waiting for the next satellite image to come out.
Member Since: October 28, 2006 Posts: 57 Comments: 30830
385. Bamatracker
9:27 PM GMT on May 06, 2007
booooooooooo!!!! the blog is stretched!!
Member Since: May 17, 2006 Posts: 6 Comments: 1367
384. GetReal
9:27 PM GMT on May 06, 2007
I do not believe that the NHC will name this system as a sub-tropical, or tropical storm, due to political and economic considerations. The NHC probably will not want to fan the media hype of an early and very active season starting this early. If it develops further...
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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.

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