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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Whats your prediction ??
NWS STORM PREDICTION CENTER NORMAN OK
150 PM EDT SUN MAY 6 2007
SEVERE THUNDERSTORM WATCH 244 IS IN EFFECT UNTIL 800 PM EDT
FOR THE FOLLOWING LOCATIONS
AMZ454-550-555-610-630-650-651-GMZ656-657-830-850-853-856-
070000-
/O.NEW.KWNS.SV.A.0244.070506T1750Z-070507T0000Z/
CW
. ADJACENT COASTAL WATERS INCLUDED ARE
COASTAL WATERS FROM ST. AUGUSTINE TO FLAGLER BEACH FL OUT 20 NM
COASTAL WATERS FROM FLAGLER BEACH TO COCOA BEACH FL OUT 20 NM
COASTAL WATERS FROM COCOA BEACH TO JUPITER INLET FL OUT 20 NM
LAKE OKEECHOBEE
BISCAYNE BAY
COASTAL WATERS FROM JUPITER INLET TO DEERFIELD BEACH FL OUT 20 NM
COASTAL WATERS FROM DEERFIELD BEACH TO OCEAN REEF FL OUT 20 NM
COASTAL WATERS FROM CHOKOLOSKEE TO BONITA BEACH FL OUT 20 NM
COASTAL WATERS FROM EAST CAPE SABLE TO CHOKOLOSKEE FL OUT 20 NM
TAMPA BAY WATERS
COASTAL WATERS FROM TARPON SPRINGS TO SUWANNEE RIVER FL OUT 20 NM
COASTAL WATERS FROM ENGLEWOOD TO TARPON SPRINGS FL OUT 20 NM
COASTAL WATERS FROM BONITA BEACH TO ENGLEWOOD FL OUT 20 NM
SEVERE THUNDERSTORM WATCH OUTLINE UPDATE FOR WS 244
NWS STORM PREDICTION CENTER NORMAN OK
150 PM EDT SUN MAY 6 2007
SEVERE THUNDERSTORM WATCH 244 IS IN EFFECT UNTIL 800 PM EDT
FOR THE FOLLOWING LOCATIONS
FLC001-009-011-015-017-021-027-035-043-049-051-053-055-057-061-
069-071-075-081-083-085-086-087-093-095-097-099-101-103-105-107-
111-115-117-119-127-070000-
/O.NEW.KWNS.SV.A.0244.070506T1750Z-070507T0000Z/
FL
. FLORIDA COUNTIES INCLUDED ARE
ALACHUA BREVARD BROWARD
CHARLOTTE CITRUS COLLIER
DESOTO FLAGLER GLADES
HARDEE HENDRY HERNANDO
HIGHLANDS HILLSBOROUGH INDIAN RIVER
LAKE LEE LEVY
MANATEE MARION MARTIN
MIAMI-DADE MONROE OKEECHOBEE
ORANGE OSCEOLA PALM BEACH
PASCO PINELLAS POLK
PUTNAM SARASOTA SEMINOLE
ST. LUCIE SUMTER VOLUSIA
Still sounds a bit vague, Kris.
Whats your prediction ??
Far too early for me to throw out a forecast.We don't even have a low yet.
I will agree with the ECMWF,nogaps,Ukmet and even some of the GFS.... At first the storm will be strong..but nontropical...a gale center....but as it slowly picks up some tropical characteristics...it will weaken...cause it wont be a non tropical system as its in transition....then as it comes close to Floridas NE coast and St Augustine...the LLC will seperate from the mid and upper low and be on its west side and get pushed sw between the mid and upper low now to its E and the weak ridge over the NE gulf of mexico. This is the atmospheric synopsis.
Sounds interesting. I wanna hear, not that i'm saying your wrong, what the NHC has to say, cause they are the people who know what they are talkign about. I will agree with the fact that it will most likely not be a MID-South Florida storm as the high will weaken as it moves to the west.
(12:50 pm EDT)
1650 GMT on 05/06/2007:
Unit of Measure: Time Zone:
Click on the graph icon in the table below to see a time series plot of the last five days of that observation.
Wind Direction (WDIR): S ( 180 deg true )
Wind Speed (WSPD): 23.3 kts
Wind Gust (GST): 31.1 kts
Wave Height (WVHT): 5.6 ft
Dominant Wave Period (DPD): 5 sec
Average Period (APD): 4.6 sec
Atmospheric Pressure (PRES): 29.81 in
Pressure Tendency (PTDY): -0.10 in ( Falling Rapidly )
Air Temperature (ATMP): 64.6 °F
Water Temperature (WTMP): 68.5 °F
Dew Point (DEWP): 63.7 °F
Combined plot of Wind Speed, Gust, and Air Pressure
REGARDING THE DEVELOPMENT AND ASSOCIATED FRONTAL STRUCTURE OF A
STRONG LOW PRESSURE CENTER OFF OF THE SE COAST OF UNITED
STATES LATER TODAY THROUGH TUESDAY. THIS IS EXPECTED TO BRING
SIGNIFICANT MARINE IMPACTS TO THE NW PORTION OF THE AREA INTO
EARLY NEXT WEEK...INCLUDING GALE FORCE WINDS AND LARGE NLY
SWELLS. SEVERAL MARINE ADVISORIES/WARNINGS ARE ALREADY IN EFFECT
ALONG THE EASTERN COAST OF U.S FROM SOUTH FLORIDA TO BEYOND THE
CAROLINAS. SHOWERS AND TSTMS HAVE INCREASED AHEAD OF THE
BACKDOOR FRONT CURRENTLY EXTENDING FROM A 1012 MB SFC LOW NEAR
THE OUTER BANK TO SOUTH GEORGIA. THIS CONVECTIVE ACTIVITY IS
MOVING SOUTH CLIPPING NE FLORIDA. A SFC TROUGH REMAINS OVER THE
W ATLC AND EXTENDS FROM 29N60W TO THE REGIONAL WATERS OF PUERTO
RICO. THIS TROUGH HAS A 1012 MB LOW ATTACHED NEAR 28N60W. LATEST
VIS SAT IMAGERY IS SHOWING A COUPLE OF LOW LEVEL SWIRLS ALONG
THE TROUGH AXIS. MOST OF THE SHOWER ACTIVITY REMAINS WITHIN 80
NM E OF THE TROUGH WHERE MORE UPPER SUPPORT EXISTS...WITH
DIFFLUENCE BETWEEN THE TROUGHING IN THE WRN ATLC AND RIDGING IN
THE CENTRAL ATLC.
Maybe bottoms out at 998mb.
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SUN MAY 06 2007
...DISCUSSION...
GULF OF MEXICO...
MODERATE TO STRONG RETURN FLOW CONTINUES TO DOMINATE THE GULF MAINLY W OF 90W WHERE A TIGHTER PRES GRADIENT EXISTS DUE TO LOWER PRESSURE OVER MEXICO. EARLIER QUIKSCAT PASS SHOWED SLY WINDS OF 15 TO 25 KT. AN UPPER RIDGE IS BUILDING ACROSS THE GULF AND IS SPREADING UPPER LEVEL MOISTURE/HIGH CLOUDS EWD INTO THE GULF ESPECIALLY W OF 90W. MOSTLY DRY MID TO UPPER AIR IS OVER THE ERN PORTION WITH NW FLOW ASSOCIATED WITH A STRONG UPPER TROUGH DIGGING OFF THE EASTERN SEABOARD. BACKDOOR FRONT ASSOCIATED WITH THIS TROUGH WILL AFFECT THE MIDDLE AND ERN GULF LATE TONIGHT INTO MON. STRONG HIGH PRES WILL FOLLOW THE FRONTAL BOUNDARY GIVING THE AREA MODERATE TO STRONG NE-E FLOW. THIS
WINDS ARE EXPECTED TO INCREASE TO 20-25 KT LATE TONIGHT.
CARIBBEAN SEA...
LIGHT TO MODERATE TRADES ARE BLOWING ACROSS MUCH OF THE BASIN DUE TO WEAK PRES GRADIENT OVER THE REGION. ALOFT...AN UPPER TROUGH IS DIGGING INTO THE WESTERN CARIBBEAN...WHILE AN UPPER HIGH CENTERED OFF NE SOUTH AMERICA EXTENDS A BROAD RIDGE OVER THE REMAINDER OF THE BASIN. THE RIDGE ALSO EXTENDS WWD FROM VENEZUELA TO COSTA RICA. SWLY WINDS ON THE WESTERN PERIPHERY OF THE RIDGE ARE TRANSPORTING ABUNDANT UPPER LEVEL MOISTURE/HIGH CLOUDS FROM THE EPAC ITCZ LOCATED JUST SOUTH OF PANAMA/COSTA RICA NEWD THROUGH THE CENTRAL AND NECARIBBEAN. UPPER DIFFLUENCE AND THE CLOSE PROXIMITY OF THE EPAC ITCZ ARE ENHANCING CLUSTERS OF MODERATE TO ISOLATED STRONG CONVECTION OVER PANAMA...COSTA RICA AND THE SW CARIBBEAN. FAIRLY WEAK PRES GRADIENT WILL KEEP TRADES IN THE LIGHT TO MODERATE CATEGORY OVER THE NEXT COUPLE OF DAYS.
ATLANTIC...
GLOBAL MODELS HAVE CONTINUED TO COME INTO BETTER AGREEMENT REGARDING THE DEVELOPMENT AND ASSOCIATED FRONTAL STRUCTURE OF A STRONG LOW PRESSURE CENTER OFF OF THE SE COAST OF UNITED
STATES LATER TODAY THROUGH TUESDAY. THIS IS EXPECTED TO BRING SIGNIFICANT MARINE IMPACTS TO THE NW PORTION OF THE AREA INTO EARLY NEXT WEEK...INCLUDING GALE FORCE WINDS AND LARGE NLY SWELLS. SEVERAL MARINE ADVISORIES/WARNINGS ARE ALREADY IN EFFECT ALONG THE EASTERN COAST OF U.S FROM SOUTH FLORIDA TO BEYOND THE CAROLINAS. SHOWERS AND TSTMS HAVE INCREASED AHEAD OF THE BACKDOOR FRONT CURRENTLY EXTENDING FROM A 1012 MB SFC LOW NEAR THE OUTER BANK TO SOUTH GEORGIA. THIS CONVECTIVE ACTIVITY IS MOVING SOUTH CLIPPING NE FLORIDA. A SFC TROUGH REMAINS OVER THE W ATLC AND EXTENDS FROM 29N60W TO THE REGIONAL WATERS OF PUERTO RICO. THIS TROUGH HAS A 1012 MB LOW ATTACHED NEAR 28N60W. LATEST VIS SAT IMAGERY IS SHOWING A COUPLE OF LOW LEVEL SWIRLS ALONG THE TROUGH AXIS. MOST OF THE SHOWER ACTIVITY REMAINS WITHIN 80 NM E OF THE TROUGH WHERE MORE UPPER SUPPORT EXISTS...WITH DIFFLUENCE BETWEEN THE TROUGHING IN THE WRN ATLC AND RIDGING IN THE CENTRAL ATLC.
MUCH OF THE REMAINDER OF THE ATLC DISCUSSION AREA IS DOMINATED BY THE SRN PERIPHERY OF A QUASI-STATIONARY 1033MB SFC HIGH S OF
THE AZORES NEAR 35N28W. THIS IS GIVING THE AREA MODERATE TO FRESH TRADES AND MOSTLY FAIR WEATHER WITH ONLY PATCHES OF LOW LEVEL CLOUDS. THERE IS AN UPPER LOW NEAR 28N25W BUT IT DOES NOT APPEAR TO BE GENERATING ANY SIGNIFICANT WEATHER.
Although the person who made the predict. could very well be correct.
But then, so could everyone else.
Its great, isnt it ?
Anyone agree?
south east coast IR
south east coast WV
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