Dr. Jeff Masters' WunderBlog

Greensburg tornado an EF-5; coastal storm will bring 3-5' storm surge to Carolinas
Posted by: Dr. Jeff Masters, 02:42 PM GMT del 07 Maggio 2007 +4
The huge, 1.4 mile-wide tornado that devastated Greensburg, KS on Friday night, May 4, was an EF-5 tornado on the Enhanced Fujita Scale. A preliminary damage survey by the National Weather Service found that the storm likely had 205 mph winds, putting it just above the 200 mph wind threshold for an EF5 rating. This is the first tornado ever rated as an EF5 using the new scale, adopted in February of 2007, and the first tornado to receive a "5" rating since the May 3, 1999 Moore-Bridge Creek tornado that devastated the southern suburbs of Oklahoma City. Had the Greensburg tornado hit downtown Chicago, the death toll could have easily been in the thousands, as I discussed last month in my blog, "Big Wind in the Windy City".

The severe storm action finally quieted down yesterday in Kansas and the Plains; only 11 reports of tornadoes were received, compared to 93 on Saturday and 33 on Friday. The severe weather action should stay at a slow simmer through Wednesday over the Plains; the Storm Prediction Center (SPC) has portions of the region under its "Slight Risk" area for severe weather through Wednesday. Flooding is a major concern now; most of eastern Kansas, plus large portions of Oklahoma, Texas, Missouri, Iowa, Nebraska, and South Dakota are under flood warnings. More heavy thunderstorm rains during the week are expected to add to the problem.

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.


Wunderblogger Mike Theiss was out chasing the weekend storms; be sure to tune into his blog over the next few days to read his chase accounts.


Figure 1. Visible satellite image of the May 7, 2007 coastal storm.

Coastal Carolina storm
A powerful non-tropical low pressure system formed off the coast of North Carolina last night, and is bringing tropical storm-force winds as high as 55 mph to the waters offshore the Carolina coast, according to the latest QuikSCAT satellite wind estimates. The North Carolina Diamond Shoals buoy had 17 foot seas and sustained winds of 43 mph at 9am EDT this morning, and buoy 41001 about 175 miles east of Cape Hatteras recorded sustained winds of 62 mph gusting to 80 mph at 1am this morning. Seas were 41 feet at this buoy this morning! The strong winds will bring 10-20 foot seas and significant beach erosion to the shores of North Carolina, South Carolina, and northeast Florida through Wednesday. A 3-5 foot storm surge is expected along portions of the North Carolina coast through Tuesday morning. The latest set of computer model runs have the storm drifting slowly southwest, and bring it ashore between the South Carolina and northern Florida coast on Wednesday. The storm will start to develop thunderstorm activity and a warm core, but will probably not have time to become fully subtropical and become Subtropical Storm Andrea. However, the storm is only expected to weaken slowly, and will have an impact similar to a tropical storm in regards to offshore winds and coastal flooding today and Tuesday. If the storm does indeed make landfall on Wednesday as expected, it will most likely be of tropical depression strength, with top sustained winds around 30-35 mph. Heavy rains of 1-3 inches can be expected to the north of where the center makes landfall, but rains will not be as significant as what a tropical storm would bring.

I'll have an update on this storm Tuesday morning.
Jeff Masters
Raging Waters - Mill Creek1 (Cptkirk)
Same location - evenig shots!
Raging Waters - Mill Creek1
()
Storm Cloud Formation (FT2)
Detail of Turbulance Under the Trough on 05/06/2007 in SE Iowa.
Storm Cloud Formation
Categories: Tornado
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551. kmanislander 11:32 PM GMT del 07 Maggio 2007    
thelmores

try some Head on LOL
Member Since: Agosto 19, 2006 Posts: 0 Comments: 14939
552. Drakoen 11:33 PM GMT del 07 Maggio 2007    
from the latest Infrared imagery it looks like its losing some of the little convection it has, not saying that couldn't change with daytime heating by tommorrow. Just because the system has 65 knts winds doesn't make it a tropical storm it needs thunderstorm convection wrapped around the center-warm core.
Member Since: Ottobre 28, 2006 Posts: 57 Comments: 29010
553. Thundercloud01221991 11:33 PM GMT del 07 Maggio 2007    
oh but they are 65-70 knt winds just not reliable
Member Since: Agosto 1, 2006 Posts: 28 Comments: 3670
554. i12BNEi 11:34 PM GMT del 07 Maggio 2007    
If this is only the 9th May storm,Wouldn't that mean that there was only a 10% chance that this would even happen at all?
555. StormJunkie 11:34 PM GMT del 07 Maggio 2007    
lmao kman!

I have always wnated to know this, how do you know there are contaminated barbs other then looking at the satellite?
Member Since: Agosto 17, 2005 Posts: 26 Comments: 15218
557. RL3AO 11:36 PM GMT del 07 Maggio 2007    
Possible tornadic cell just NW of Eagle Pass, TX
559. Thundercloud01221991 11:36 PM GMT del 07 Maggio 2007    
http://www.ssd.noaa.gov/goes/flt/t4/wv.jpg

a ring of thunderstorms forming around the center
Member Since: Agosto 1, 2006 Posts: 28 Comments: 3670
560. Drakoen 11:38 PM GMT del 07 Maggio 2007    
Posted By: Thundercloud01221991 at 11:36 PM GMT on May 07, 2007.

http://www.ssd.noaa.gov/goes/flt/t4/wv.jpg

a ring of thunderstorms forming around the center

not necessarily thunderstorm just looks like CDO to me. With light ot moderate in the clouds.
Member Since: Ottobre 28, 2006 Posts: 57 Comments: 29010
561. StormJunkie 11:40 PM GMT del 07 Maggio 2007    
Possible tornadic cell just NW of Eagle Pass, TX

Not again...
Member Since: Agosto 17, 2005 Posts: 26 Comments: 15218
562. Thundercloud01221991 11:40 PM GMT del 07 Maggio 2007    
Hey I just meant to say that the convection is increasing.
Member Since: Agosto 1, 2006 Posts: 28 Comments: 3670
563. kmanislander 11:41 PM GMT del 07 Maggio 2007    
SJ

Are you testing my knowledge ( or lack of it )or are you saying they are not rain contaminated ?? LOL
Member Since: Agosto 19, 2006 Posts: 0 Comments: 14939
564. cajunkid 11:43 PM GMT del 07 Maggio 2007    
If I were calling the shots at the NHC, I would be all over this. Just because...its a safe bet this thing wont become a hurricane (maybe a minimal one at best), but it can diffuse the media hype of the first storm of the season.
Member Since: Luglio 10, 2005 Posts: 3 Comments: 1239
565. kmanislander 11:44 PM GMT del 07 Maggio 2007    
Barbs suspected of being rain contaminated are always coloured in black
Member Since: Agosto 19, 2006 Posts: 0 Comments: 14939
566. RL3AO 11:44 PM GMT del 07 Maggio 2007    
IMO, which may or may not be accurate, this is still not even close to being sub-tropical.
567. StormJunkie 11:44 PM GMT del 07 Maggio 2007    
That convection is growing every so slowly...Not much as of now even that "ring" is some weak convection. The midwest has convection.

That being said, for those of y'all using the SSD or the NHC Floaters and other imagery. You are looking at older data. The Global Hydrology and Climate center imagery updates much quicker, offers a larger loop, and you can zoom in on regions. First link in the imagery section here.
Member Since: Agosto 17, 2005 Posts: 26 Comments: 15218
568. thelmores 11:46 PM GMT del 07 Maggio 2007    
put me down for Savannah..... Sorry Florida, just don't see this coming your way.... hope I am wrong....... but honestly, any rainfall along the SE coast is much needed.

not to mention, most rain I believe will be north of the center..... hate to be selfish, but I hope thats me!!!
Member Since: Settembre 8, 2005 Posts: 0 Comments: 3748
569. hurricane23 11:46 PM GMT del 07 Maggio 2007    
SST'S are just to cool to support anything tropical out there.Also quick note the GOM is showing many areas under 80 degrees.

Member Since: Maggio 14, 2006 Posts: 8 Comments: 13276
570. HurricaneFCast 11:47 PM GMT del 07 Maggio 2007    
WESTERN ATLANTIC...
THE HIGHLIGHT CONTINUES TO BE A LARGE OCCLUDED LOW PRES SYSTEM
CENTERED OFF THE SE U.S. NEAR 31N75W...ANALYZED 998 MB. A
TRAILING/BACK DOOR COLD FRONT EXTENDS FROM A TRIPLE POINT NEAR
32N67W ACROSS THE CENTRAL BAHAMAS...NRN CUBA AND THEN INTO THE
GULF OF MEXICO. A STATIONARY FRONT RUNS FROM THE TRIPLE POINT TO
52W ALONG 32N WITH TWO WEAK FRONTAL WAVES. THIS LOW PRES SYSTEM
HAS AN IMPRESSIVELY LARGE CIRCULATION BUT NOT MUCH DEEP
MOISTURE...ESPECIALLY ON ITS S SIDE. ISOLATED SHOWERS ARE WITHIN
180 NM E OF THE FRONT AND BASICALLY ANYWHERE BETWEEN 50W AND THE
FRONT ENHANCED BY UPPER SWLY FLOW. HOWEVER...WHAT IT IS
PRODUCING IS VERY STRONG WINDS AS A VERY TIGHT PRES GRADIENT HAS
SET UP BETWEEN THE LOW AND A STRONG HIGH PRES RIDGE OVER AND OFF
THE NE U.S. COASTLINE. THIS PRES GRADIENT IS PRODUCING HURRICANE
FORCE WINDS N OF THE AREA E OF THE CAROLINA COASTLINE AND STORM
FORCE CONDITIONS IN OUR AREA N OF 28N W OF 74W. SEVERAL
ADVISORIES AND WARNINGS HAVE BEEN POSTED ALONG THE COAST FROM
SOUTH FLORIDA TO BEYOND THE CAROLINAS WHERE ROUGH SURF AND VERY
DANGEROUS RIP CURRENTS ARE LIKELY OCCURRING. GLOBAL MODELS ARE
IN GOOD AGREEMENT TRACKING THE LOW WWD TOWARD THE SE COAST BUT
THERE ARE DIFFERENCES IN SPEED/TIMING. THE CURRENT FORECAST
CALLS FOR WINDS TO BEGIN SLOWLY SUBSIDING...AS THE GRADIENT
SLACKENS... FALLING BELOW GALE FORCE IN ABOUT 36 HOURS.

Member Since: Aprile 20, 2007 Posts: 7 Comments: 1482
571. HurricaneFCast 11:48 PM GMT del 07 Maggio 2007    
Updated NHC Discussion.. 8:05p.m.
Member Since: Aprile 20, 2007 Posts: 7 Comments: 1482
572. StormJunkie 11:48 PM GMT del 07 Maggio 2007    
Serious question kman. I mean when a storm is a few hundred miles away from Africa and we look at the Quickscat, how do you know you where it is raining and where it is just cloudy? Maybe it is a stupid question kman, but not testing you ☺



So Quickscat in over 60mph winds is useless? Rain or no rain?
Member Since: Agosto 17, 2005 Posts: 26 Comments: 15218
573. kmanislander 11:50 PM GMT del 07 Maggio 2007    
SJ

When you go to the QS page it says that barbs suspected of being rain contaminated are coloured in black. The QS pass posted had black barbs, hence my conclusion that rain was a factor
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574. kmanislander 11:51 PM GMT del 07 Maggio 2007    
SJ

Take a look at the note on the page linked which refers to black coloured barbs

Link
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575. hurricane23 11:52 PM GMT del 07 Maggio 2007    
Nothing new from the NHC as this system remains cold-core.Will likely run out of room before ever really getting a chance to tap into the gulfstream.
Member Since: Maggio 14, 2006 Posts: 8 Comments: 13276
576. Bamatracker 11:52 PM GMT del 07 Maggio 2007    
looks like the NHC killed the blog
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577. StormJunkie 11:55 PM GMT del 07 Maggio 2007    
Thanks kman.

Had not looked at this before. Want to know something about Quickscat? I geuss the answer to my question about the scale is in here somewhere...lol
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578. kmanislander 11:58 PM GMT del 07 Maggio 2007    
well dinner time now. BBL
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579. hurricane23 11:58 PM GMT del 07 Maggio 2007    
There's really nothing to report out there with this naked swirl.Its going to be a battle trying to fight off the dry air around it.Should come in somewere in northern florida as a weaking system.

Lastest TPC forcast
Member Since: Maggio 14, 2006 Posts: 8 Comments: 13276
580. Drakoen 11:59 PM GMT del 07 Maggio 2007    
Posted By: Bamatracker at 11:52 PM GMT on May 07, 2007.

looks like the NHC killed the blog

lol i knew it wouldn't develop. Steve Lyons on the weather channel says it has a very little chance to become subtropical.Its just a cold core now. Look at the cloud top temperatures. It system will, however still bring rain and tropical depression/storm force winds to the South East.
Member Since: Ottobre 28, 2006 Posts: 57 Comments: 29010
581. RL3AO 12:02 AM GMT del 08 Maggio 2007    
600 posts in 10 hours for an extra-tropical low? Whats going to happen when an actual storm forms?
582. Bamatracker 12:04 AM GMT del 08 Maggio 2007    
RL..thats when it gets fun
Member Since: Maggio 17, 2006 Posts: 6 Comments: 1364
583. thelmores 12:05 AM GMT del 08 Maggio 2007    
chaos will happen!

name or not, I want rain!!!!

oh well, beats blob watchin..... nice little swirl! :)
Member Since: Settembre 8, 2005 Posts: 0 Comments: 3748
584. hurricane23 12:05 AM GMT del 08 Maggio 2007    
Should be used as a reminder that cane season is just around the corner.But kinda enjoy the quite evening around here across south florida as our naked swirl is bring in a real dry air mass down the state.
Member Since: Maggio 14, 2006 Posts: 8 Comments: 13276
585. K8eCane 12:07 AM GMT del 08 Maggio 2007    
lol i knew it wouldn't develop. Steve Lyons on the weather channel says it has a very little chance to become subtropical.Its just a cold core now. Look at the cloud top temperatures. It system will, however still bring rain and tropical depression/storm force winds to the South East.




thats scary that you know it wont develop because steve lyons just wrote it in stone
Member Since: Aprile 26, 2006 Posts: 5 Comments: 2371
586. kmanislander 12:07 AM GMT del 08 Maggio 2007    
hurricane 23

you better remove that before someone has a fit lmao
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587. StormJunkie 12:08 AM GMT del 08 Maggio 2007    
oh well, beats blob watchin..... nice little swirl! :)

lmao, and I second that thel ☺
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588. Tazmanian 12:08 AM GMT del 08 Maggio 2007    
this to yet you all no if this was a STS or TS we would not no that in tell nov or DEC
Member Since: Maggio 21, 2006 Posts: 5088 Comments: 111346
589. weatherblog 12:09 AM GMT del 08 Maggio 2007    
Posted By: cajunkid at 11:43 PM GMT on May 07, 2007.

If I were calling the shots at the NHC, I would be all over this. Just because...its a safe bet this thing wont become a hurricane (maybe a minimal one at best), but it can diffuse the media hype of the first storm of the season.


True, doesn't seem to be getting the "media hype" but it's not an even possible development, so that's why. Also it's only early May, so another reason why.


Another thing, I doubt this will develop. We had many, many, many, many storms similiar to this last year. There was too much dry air or in other words; not in a good situation. I mean, it's only May. Seriously speaking, there is very little to no chance of this becoming a hurricane. Maybe the MOST becoming a mimimal-subtropical storm (15% in my opinion) and even less than 15% for it becoming tropical.
Member Since: Luglio 10, 2006 Posts: 27 Comments: 1623
590. kmanislander 12:14 AM GMT del 08 Maggio 2007    
H23

I am kinda hoping that the " swirl " will dig far enough S to push a little rain our way. Its like a dust bowl in the NW Caribbean
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591. Bamatracker 12:14 AM GMT del 08 Maggio 2007    
how it air temperature measured at sea? for intsance to determine the temp in a system such as our low today
Member Since: Maggio 17, 2006 Posts: 6 Comments: 1364
592. RL3AO 12:17 AM GMT del 08 Maggio 2007    
air temp is measured by bouys and other weather stations
593. i12BNEi 12:19 AM GMT del 08 Maggio 2007    
Could this make it to the gulf?
Nice site SJ.
594. Bamatracker 12:19 AM GMT del 08 Maggio 2007    
so the info on air temperature is going to be limited over the ocean?
Member Since: Maggio 17, 2006 Posts: 6 Comments: 1364
595. cajunkid 12:19 AM GMT del 08 Maggio 2007    
cool site Link
Member Since: Luglio 10, 2005 Posts: 3 Comments: 1239
596. hurricane23 12:20 AM GMT del 08 Maggio 2007    
Many bad examples, including the "perfect storm" in 1991, were owed to hybrid (subtropical) systems. These account for less than 2% of large-scale cyclone types aside from tropical and extratropical (mid lattitude / wave) cyclones.

Right now it looks like this hybrid type system is weakening, but has already created a large wave setup with gusts near hurricane force (not a true hurricane, so you will see "storm warning", but extra "wording" of hurricane forced winds outside a tropical system).

Needless to say, 20 foot plus swells are possible along SE coast into FL, something that has not happened in some time.Iam suspecting there will be severe beach erosion, flooding, and wave damage even long after the winds die down.
Member Since: Maggio 14, 2006 Posts: 8 Comments: 13276
598. MZT 12:21 AM GMT del 08 Maggio 2007    
It may be a dull, dry airmass, but it's also quite large. It looks like a frontal boundary extending all the way to Arkansas and Missouri is stirring up convenction out there.
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599. StormJunkie 12:22 AM GMT del 08 Maggio 2007    
Thanks i12 ☺
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600. DocBen 12:24 AM GMT del 08 Maggio 2007    
What happens if this thing just stays a heck of a windstorm with little moisture ... and then comes ashore to fan the flames of the fires?
Member Since: Maggio 16, 2006 Posts: 0 Comments: 96
601. melwerle 12:24 AM GMT del 08 Maggio 2007    
Jeez - a person goes and gets a rum and coke and there are five more pages of stuff to sort through. Hey everyone - what's going on with this thing?
Member Since: Giugno 28, 2006 Posts: 12 Comments: 1837

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About JeffMasters
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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