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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684. HurricaneFCast
12:44 AM GMT on May 07, 2007
Hurricane23- What's the name of the radar software you use?
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683. dnalia
12:44 AM GMT on May 07, 2007
A Tornado Warning remains in effect until 915 PM EDT for eastern
Miami-Dade County...

At 833 PM EDT... National Weather Service Doppler radar continued to
indicate a possible tornado 6 miles west of Miccosukee resort... or about
17 miles west of Kendall... moving southeast at 30 mph.

The tornado will be near...
intersection krome and Kendall drive by 845 PM EDT...
Kendall Lakes by 850 PM EDT...
The Hammocks and West Kendall by 855 PM EDT...
Country Walk... Inlikita and Metro zoo by 900 PM EDT...
Richmond Heights and the falls by 905 PM EDT...
Goulds by 910 PM EDT...


ACK! I guess I better get my butt downstairs to an interior room (we don't have basements)
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682. Chicklit
12:42 AM GMT on May 07, 2007
Hey guys...my friend lives in Plantation, FL (33323) Any tornadoes spotted down there?
Member Since: July 11, 2006 Posts: 14 Comments: 11047
681. hurricaneman23
12:42 AM GMT on May 07, 2007
where do u live shoals
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680. stormhank
12:41 AM GMT on May 07, 2007
I saw a couple models sayin loop south southwest and comes into florida.then dissapates. maybe some beneficial rain anyways
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679. Tazmanian
5:41 PM PDT on May 06, 2007
lol
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678. shoals
12:40 AM GMT on May 07, 2007
I can tell you its gusting well over 50 mph here...sometimes closer to 60 mph.
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676. HIEXPRESS
12:37 AM GMT on May 07, 2007
BTW: what's the outflow look like over the coastal low?
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675. stormhank
12:36 AM GMT on May 07, 2007
I just got home from work JP.. whats the models sayin about it? tropical perhaps later on or just sub tropical?
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674. HurricaneRoman
12:25 AM GMT on May 07, 2007
Finally! The rain came...its raining hard and its probably gusting to around 40 at times
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672. HIEXPRESS
12:32 AM GMT on May 07, 2007
Quit flogging that poor frontal low & look at Tejas later this week. See anything upstairs? Maybe a little divergence? (Only Models, I know.)

SPC AC 060729

DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0229 AM CDT SUN MAY 06 2007

VALID 081200Z - 091200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE SRN
PLAINS...

...SRN PLAINS...
A SLOW MOVING UPPER-LEVEL TROUGH OVER THE ROCKIES IS FORECAST TO
ACCELERATE EWD TUESDAY WITH LARGE-SCALE ASCENT INCREASING ACROSS
MUCH OF THE SRN PLAINS TUESDAY AFTERNOON. AT THE SFC...A COLD FRONT
SHOULD EXIST FROM THE CNTRL PLAINS SSWWD INTO PARTS OF WEST TX. EAST
OF THIS BOUNDARY...POCKETS OF MODERATE INSTABILITY ARE FORECAST AND
THIS COMBINED WITH INCREASING ASCENT ASSOCIATED WITH THE APPROACHING
UPPER-LEVEL TROUGH SHOULD BE FAVORABLE FOR MCS DEVELOPMENT. ATTM
FORECAST SOUNDINGS SHOW MODERATE TO STRONG VERTICAL SHEAR PROFILES
SUGGESTING A THREAT FOR SUPERCELLS WILL EXIST IN WEST TX WITH A
POTENTIAL FOR AN ENHANCED SEVERE THREAT. IN ADDITION...MODELS
DEVELOP A LOW-LEVEL JET OVER WEST TX IN RESPONSE TO THE UPPER-LEVEL
TROUGH WHICH WOULD ALSO ENHANCE THE SEVERE WEATHER THREAT.
CONFIDENCE IN THIS SCENARIO WILL LIKELY INCREASE WITH NEW MODEL RUNS
AND THIS AREA MAY NEED TO BE UPGRADED IN LATER OUTLOOKS.

..BROYLES.. 05/06/2007

Graphic of UL winds Removed for brevity- no longer current
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670. HurricaneFCast
12:32 AM GMT on May 07, 2007
Hurricane23- PLEASE tell me the name of that software, that is the type of radar I need. ??
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669. stormhank
12:32 AM GMT on May 07, 2007
Hey Jp how you doing?? whats your thinking on the SE coast system? any rain for Ga or florida?
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667. BoyntonBeach
12:30 AM GMT on May 07, 2007
It's still raining here...we've cooled off quite a bit though..
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665. Patrap
7:29 PM CDT on May 06, 2007
...3
Member Since: July 3, 2005 Posts: 415 Comments: 125628
664. Patrap
7:27 PM CDT on May 06, 2007
Cell x-8 has some rotation noted too on the radar above
Member Since: July 3, 2005 Posts: 415 Comments: 125628
663. hurricaneman23
12:27 AM GMT on May 07, 2007
H23 do u think the low off the carolinas will develop into a tropical storm?
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662. hurricane23
8:28 PM EDT on May 06, 2007
G
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661. Skyepony (Mod)
12:26 AM GMT on May 07, 2007
URGENT - WEATHER MESSAGE
NATIONAL WEATHER SERVICE JACKSONVILLE FL
312 PM EDT SUN MAY 6 2007

FLZ024-025-032-033-037-038-GAZ153-154-165-166-071100-
/O.CAN.KJAX.LW.Y.0014.070506T2000Z-070509T0000Z/
/O.NEW.KJAX.WI.Y.0003.070506T2000Z-070509T0000Z/
NASSAU-DUVAL-CLAY-ST JOHNS-PUTNAM-FLAGLER-INLAND GLYNN-
COASTAL GLYNN-INLAND CAMDEN-COASTAL CAMDEN-
INCLUDING THE CITIES OF...FERNANDINA BEACH...JACKSONVILLE...
GREEN COVE SPRINGS...ST AUGUSTINE...PALATKA...PALM COAST...
BRUNSWICK...WOODBINE...ST MARYS
312 PM EDT SUN MAY 6 2007

...WIND ADVISORY IN EFFECT UNTIL 8 PM EDT TUESDAY FOR COASTAL AREAS...
...LAKE WIND ADVISORY IS CANCELLED...

THE NATIONAL WEATHER SERVICE IN JACKSONVILLE HAS ISSUED A WIND
ADVISORY...WHICH IS IN EFFECT UNTIL 8 PM EDT TUESDAY. THE LAKE
WIND ADVISORY HAS BEEN CANCELED.

A RAPIDLY DEEPENING LOW PRESSURE CENTER OFF THE NORTH CAROLINA
COAST WILL DRIFT SOUTH THROUGH TONIGHT AND THEN WILL MOVE SLOWLY
WESTWARD ON MONDAY THROUGH WEDNESDAY. AS IT APPROACHES THE REGION
WINDS WILL INCREASE OVER THE COASTAL COUNTIES AS WELL AS CLAY AND
PUTNAM COUNTIES. AT THIS TIME...THE STRONGEST WINDS ARE EXPECTED
OVER THE IMMEDIATE BEACHES...THE INTRA COASTAL WATERWAY...AND ST
JOHNS RIVER. NORTHEAST WINDS OF 25 TO 30 MPH WITH GUSTS TO 35 MPH
WILL BE LIKELY.

MINOR DAMAGE TO TREES...POWER LINES...AND PROPERTY ARE POSSIBLE
WITH WIND OF THIS MAGNITUDE.

MOTORISTS IN HIGH PROFILES VEHICLES ARE ADVISED TO USE CAUTION
UNTIL THE WIND SUBSIDES.

STRONG WINDS CAN TOPPLE TREES...BLOW WEAKENED ROOFS OFF HOUSES...
AND DOWN POWER LINES. TAKE PRECAUTIONS TO SECURE TRASH CANS...
LAWN FURNITURE...AND ANY OTHER LOOSE OUTDOOR OBJECTS.

SMALL BOATS WILL BE ESPECIALLY PRONE TO CAPSIZING. BOATERS IN THE
ADVISORY AREA SHOULD AVOID OPEN WATER AND STAY CLOSE TO SHORE IN
WIND PROTECTED INLETS. HIGH PROFILE VEHICLES SHOULD USE EXTRA
CAUTION WHEN TRAVELING AS WELL.


$$


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660. HurricaneFCast
12:26 AM GMT on May 07, 2007
JFLORIDA- Where do you live? I'm in North Florida as well.
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658. stormhank
12:22 AM GMT on May 07, 2007
Hey guys whats latest on SE coast system? is florida going to be affected?
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656. Patrap
7:24 PM CDT on May 06, 2007
TVS on the RADAR...3
Member Since: July 3, 2005 Posts: 415 Comments: 125628
655. hurricaneman23
12:23 AM GMT on May 07, 2007
yes sir tornade warning for central dade county
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654. hurricane23
8:20 PM EDT on May 06, 2007
Extremely heavy rain and continues lighting...

TONADO WARNING FOR MIAMI DADE COUNTY!
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653. shoals
12:18 AM GMT on May 07, 2007
Its really blowing here in Hatteras now!!
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651. Patrap
7:18 PM CDT on May 06, 2007
Wind ,rain,hail?..all 3?..We need the skinny on it! Invest in Binocular cam,they only 40bucks. Cheaper than software.
Member Since: July 3, 2005 Posts: 415 Comments: 125628
650. Hellsniper223
12:18 AM GMT on May 07, 2007
Posted By: Patrap at 12:17 AM GMT on May 07, 2007.

Define nailed for us 23!



Ohh.. Please don't... I think a few brave souls have been banned for such things... LOL
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649. Patrap
7:16 PM CDT on May 06, 2007
Define nailed for us 23!
Member Since: July 3, 2005 Posts: 415 Comments: 125628
648. Hellsniper223
12:14 AM GMT on May 07, 2007
Posted By: hurricaneman23 at 12:14 AM GMT on May 07, 2007.

where is the most likely landfall for a major hurricane this year?


SE FL... Gulf Coast...
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647. hurricane23
8:14 PM EDT on May 06, 2007
GUYS IAM GETTING NAILED RIGHT NOW!!!
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646. HurricaneFCast
12:14 AM GMT on May 07, 2007
Hman23--- Florida. 70% Chance according to Dr. Gray. That's what I remember hearing, correct me if i'm wrong someone.
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645. Patrap
7:12 PM CDT on May 06, 2007
MMS link for those who love the Oil Industry...Link
Member Since: July 3, 2005 Posts: 415 Comments: 125628
644. Bamatracker
12:13 AM GMT on May 07, 2007
im going to tell the truth...ill just drive over and beat down anybody who disagrees with me.....LOL!!!
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642. hurricaneman23
12:11 AM GMT on May 07, 2007
where is the most likely landfall for a major hurricane this year?
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641. HurricaneFCast
12:11 AM GMT on May 07, 2007
Lol JP, i'm sure things get heated during actual Hurricane Season. I can already tell by the reactions tonight.
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639. GetReal
12:11 AM GMT on May 07, 2007
Well I have to get back to work... Let's just sit back and see how this is handled by the NHC as it plays out... Bye for now...
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638. MTJax
12:11 AM GMT on May 07, 2007
Here is another good starter link to the
NOAA's Climate Prediction Center (CPC)
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637. weatherguy03
8:11 PM EDT on May 06, 2007
JP, just dont let him come to my blog!!..LOL J/K HFCast. Have a good evening.
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636. melwerle
12:10 AM GMT on May 07, 2007
ok kids - have a great night - i guess i have to go watch tv with hubby before he disconnects my weather station and throws it in the swamp.

(I'll check back after he falls asleep! lol!)

I'm SUCH a geek.
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635. HurricaneFCast
12:07 AM GMT on May 07, 2007
GetReal-- Haha. That's a little extreme. It wouldn't reach 85-90 a barrel. It struggled to reach 67 a barrel this past week even with all that's going on in Nigeria and the incredibly high demand. Summer driving season is on the way however, that is not good. If we get a Landfalling Major Hurricane this season, it will not be good, especially if it Hits somewhere along the Gulf Coast.. It would be disastrous to the oil rigs there and could lead to a dollar per gallon jump in gas, as we saw with Katrina. Not good.
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634. Patrap
7:10 PM CDT on May 06, 2007
Im all Jazz Fested out...LOL. OLd Links today.
Member Since: July 3, 2005 Posts: 415 Comments: 125628

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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.