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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934. weathermanwannabe
3:57 PM GMT on May 07, 2007
Whatever from this low eventually takes, any rainmaker for the S.E. is a good thing
Member Since: August 8, 2006 Posts: 0 Comments: 9400
933. crackerlogic
3:19 PM GMT on May 07, 2007
thelmores

the 40 foot waves are out to sea, near shore is is 6-8 feet, with 10 sec in between sets, good surfing times!!!!!!!!!!!!
932. thelmores
2:53 PM GMT on May 07, 2007
NEW BLOG!!!
Member Since: September 8, 2005 Posts: 0 Comments: 3805
931. thelmores
2:52 PM GMT on May 07, 2007
man..... feel sorry for anybody in that surf!!!

40 foot waves are huge!!! (duh!)
Member Since: September 8, 2005 Posts: 0 Comments: 3805
930. SavannahStorm
2:48 PM GMT on May 07, 2007
Conditions at 41001 as of
(9:50 am EDT)
1350 GMT on 05/07/2007:

Wind Direction (WDIR): ENE ( 70 deg true )
Wind Speed (WSPD): 36.9 kts
Wind Gust (GST): 46.6 kts
Wave Height (WVHT): 40.7 ft


40 foot waves!
Member Since: September 22, 2005 Posts: 18 Comments: 2343
929. StormJunkie
2:43 PM GMT on May 07, 2007
Thundercloud, please resize your image to a max of 640 on the width!

Thanks
Member Since: August 17, 2005 Posts: 26 Comments: 16874
928. SavannahStorm
2:43 PM GMT on May 07, 2007
AMZ374-072115-
/O.CON.KCHS.SR.W.0001.000000T0000Z-070508T2200Z/
WATERS FROM SAVANNAH GA TO ALTAMAHA SOUND GA EXTENDING FROM 20 TO
60 NM-
547 AM EDT MON MAY 7 2007

STORM WARNING REMAINS IN EFFECT THROUGH TUESDAY AFTERNOON


TODAY
NE WINDS 30 KT WITH GUSTS UP TO 50 KT...BECOMING N.
SEAS 12 TO 15 FT... BUILDING TO 12 TO 17 FT IN THE AFTERNOON.

TONIGHT
N WINDS 30 TO 35 KT WITH GUSTS UP TO 50 KT. SEAS 12 TO
16 FT. A SLIGHT CHANCE OF SHOWERS AFTER MIDNIGHT.

TUE
N WINDS 30 TO 35 KT WITH GUSTS UP TO 50 KT. SEAS 12 TO 16 FT.
A CHANCE OF SHOWERS. TSTMS LIKELY IN THE AFTERNOON.

TUE NIGHT
N WINDS 30 TO 35 KT WITH GUSTS UP TO 45 KT. SEAS 10 TO
15 FT. SHOWERS AND TSTMS LIKELY.
Member Since: September 22, 2005 Posts: 18 Comments: 2343
927. Thundercloud01221991
2:40 PM GMT on May 07, 2007
They have downgraded the north most Storm Warning to a Gale Warning
most likely because it is heading south/ SouthWest
Member Since: August 1, 2006 Posts: 28 Comments: 3716
925. Thundercloud01221991
2:39 PM GMT on May 07, 2007
http://radar.weather.gov/radar_lite.php?rid=mhx&product=N0Z&loop=yes
Member Since: August 1, 2006 Posts: 28 Comments: 3716
923. SavannahStorm
2:37 PM GMT on May 07, 2007
Maybe it doesn't quite look like a duck yet. A goose, maybe? Or perhaps a platypus.
Member Since: September 22, 2005 Posts: 18 Comments: 2343
922. Thundercloud01221991
2:36 PM GMT on May 07, 2007


Some 65kt wind barbs however rain contaminated
Member Since: August 1, 2006 Posts: 28 Comments: 3716
920. spiceymonster
2:34 PM GMT on May 07, 2007
This might be a STRECH!!! but I would love for this thing to hit SE GA, then go right down the middle of FLA, then if it can make it to the gulf and re-energize into something then go back up GA in SC where I am.
Member Since: February 10, 2002 Posts: 1 Comments: 158
919. MTJax
2:34 PM GMT on May 07, 2007
Did you see it was listed at 998MB at 0800TWDAT?
918. thelmores
2:32 PM GMT on May 07, 2007


looks like the rain shield is increasing in intensity..... I wanna west cast for rain purposes.... GO WEST 90L, GO WEST! LOL
Member Since: September 8, 2005 Posts: 0 Comments: 3805
917. Thundercloud01221991
2:30 PM GMT on May 07, 2007
I think they are waiting to have some deep convection to develop near the center not at the edge
Member Since: August 1, 2006 Posts: 28 Comments: 3716
916. sporteguy03
2:29 PM GMT on May 07, 2007
I question the development of this system wouldn't NOAA fly a plane in there if it is serious? Wouldn't Dr.Masters post a new blog???
Member Since: July 7, 2005 Posts: 0 Comments: 5417
915. thelmores
2:26 PM GMT on May 07, 2007
http://www.ssd.noaa.gov/PS/TROP/positions.html
Member Since: September 8, 2005 Posts: 0 Comments: 3805
914. Thundercloud01221991
2:26 PM GMT on May 07, 2007
http://www.ssd.noaa.gov/PS/TROP/positions.html
Member Since: August 1, 2006 Posts: 28 Comments: 3716
913. spiceymonster
2:25 PM GMT on May 07, 2007
you would think the smoke would have the same reaction like dust from the Sahara.
Member Since: February 10, 2002 Posts: 1 Comments: 158
911. Thundercloud01221991
2:23 PM GMT on May 07, 2007
The Convection is begining to cut the dry air from getting into the kids
Member Since: August 1, 2006 Posts: 28 Comments: 3716
910. SavannahStorm
2:21 PM GMT on May 07, 2007
http://www.ssd.noaa.gov/goes/flt/t1/wv.jpg

It's eating up all the ultra-dry air over SE GA that has been fueling the fires. On a side note- has there been any research on the effect of smoke from large wildfires on the development of storm systems? This thing is pulling the smoke from the Waycross fire right into it.
Member Since: September 22, 2005 Posts: 18 Comments: 2343
909. Thundercloud01221991
2:20 PM GMT on May 07, 2007
YES 90L exists according to SSL
Member Since: August 1, 2006 Posts: 28 Comments: 3716
907. thelmores
2:14 PM GMT on May 07, 2007
90L looks almost stationary now..... seems to be just east of the Gulf Stream...... If it were positioned over the warmer waters of the gulf stream, could aid in transition to warm core???
Member Since: September 8, 2005 Posts: 0 Comments: 3805
906. spiceymonster
2:13 PM GMT on May 07, 2007
I am more of a reader, but I will post when I have something THOUGHTFULL to say. Sorry if I ruffle any feathers.
Member Since: February 10, 2002 Posts: 1 Comments: 158
905. StormJunkie
2:11 PM GMT on May 07, 2007
I am with you on that spicey, and nice to meet you.
Member Since: August 17, 2005 Posts: 26 Comments: 16874
904. StormJunkie
2:11 PM GMT on May 07, 2007
Yea, not sure thel. Looks like it may be moving almost due S right now. If that continues it will not be til later in the week that it gives us a chance for rain. Also, due south is moving it away from the warmer waters of the Gulf Stream.

Going to be real interested to see if it can work this dry air out. It is still pulling it in pretty good right now, but it does look like moisture is increasing on the NW side of the system The radar shows that rain shield increasing in intensity.
Member Since: August 17, 2005 Posts: 26 Comments: 16874
903. spiceymonster
2:10 PM GMT on May 07, 2007
I want this thing to get into SE GA, they need the RAIN!!!
Member Since: February 10, 2002 Posts: 1 Comments: 158
902. thelmores
2:08 PM GMT on May 07, 2007
SJ, you may get skirted, but it looks like Myrtle Beach will miss rain..... and we could use it!!
Member Since: September 8, 2005 Posts: 0 Comments: 3805
901. thelmores
2:06 PM GMT on May 07, 2007
hopefully Dr. Masters will give us his thoughts on the first Navy invest this morning.....

WAKE UP DR. MASTERS! LOL
Member Since: September 8, 2005 Posts: 0 Comments: 3805
900. StormJunkie
2:05 PM GMT on May 07, 2007
It would be a real nasty day to be off shore up that way thel even in a cutter, much less a dingy!

That area really gets churning when the waves and winds get this way.
Member Since: August 17, 2005 Posts: 26 Comments: 16874
899. Thundercloud01221991
2:05 PM GMT on May 07, 2007
I wonder what the NWS is going to say about it at 2 00 this afternoon I wonder if it is going to be a special feature
Member Since: August 1, 2006 Posts: 28 Comments: 3716
898. thelmores
2:03 PM GMT on May 07, 2007
Taz,

the Navy can update anytime..... I agree with Skye..... they are doing their best to ignore 9OL!

There have already been at least a couple distress calls from ships off the outer banks.... one ship being battered by 34 foot waves!

3 people were in a life raft! talking about a bad day!
Member Since: September 8, 2005 Posts: 0 Comments: 3805
897. PensacolaDoug
1:55 PM GMT on May 07, 2007
The "Blue Angels" just took off......They're gonna intercept it.....

No storms in the gulf this year.... and no westcasting...
Member Since: July 25, 2006 Posts: 0 Comments: 659
896. Patrap
1:52 PM GMT on May 07, 2007
The UNISYS GFSx Home Page..Link
Member Since: July 3, 2005 Posts: 428 Comments: 129760
895. Tazmanian
1:52 PM GMT on May 07, 2007
when is the naxt update for the navy site? may be will see 90L or are 1st name storm then
Member Since: May 21, 2006 Posts: 5091 Comments: 115453
894. franck
1:51 PM GMT on May 07, 2007
Patrap...what that is, map?
Member Since: August 30, 2005 Posts: 0 Comments: 1150
893. Patrap
1:47 PM GMT on May 07, 2007
Skye,..yall Need a good Meso like we had last Friday..or Gullywashing frog strangling TD..say around May 18th?..
Member Since: July 3, 2005 Posts: 428 Comments: 129760
892. Skyepony (Mod)
1:45 PM GMT on May 07, 2007
Hey Colby~ sorry about your site.. ST2.5 is near an STS. They are really trying hard to ignore this.

Crown~ link here

Patrap~ yeah we're so dry it's gonna take a few of these.. We're like 15" or so behind here.

Member Since: August 10, 2005 Posts: 222 Comments: 39353
891. SavannahStorm
1:44 PM GMT on May 07, 2007
The only name I'm giving this thing is the "Great Waycross Fire-Fanner". Thanks to this windbag another 20,000 acres are gonna go up in flames.
Member Since: September 22, 2005 Posts: 18 Comments: 2343
890. thelmores
1:40 PM GMT on May 07, 2007
did somebody say west??? LOL
Member Since: September 8, 2005 Posts: 0 Comments: 3805
889. crownwx
1:39 PM GMT on May 07, 2007
Colby: Where did you see the SSD classification of 2.5. Where can I find it on the internet?? Thanks
Member Since: December 27, 2004 Posts: 3 Comments: 207
887. Patrap
1:36 PM GMT on May 07, 2007
The GFSx does the same Skyepony..this no drought buster..sadly..Link
Member Since: July 3, 2005 Posts: 428 Comments: 129760
884. Patrap
1:35 PM GMT on May 07, 2007
6
Member Since: July 3, 2005 Posts: 428 Comments: 129760

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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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