Another wild night in Tornado Alley
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
A big storm moved in on the 3rd. Wasn't as bad as it looked though.
Reader Comments
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WAKE UP DR. MASTERS! LOL
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.
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.
looks like the rain shield is increasing in intensity..... I wanna west cast for rain purposes.... GO WEST 90L, GO WEST! LOL
Some 65kt wind barbs however rain contaminated
most likely because it is heading south/ SouthWest
/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.
Thanks
(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!
40 foot waves are huge!!! (duh!)
the 40 foot waves are out to sea, near shore is is 6-8 feet, with 10 sec in between sets, good surfing times!!!!!!!!!!!!
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