Rare South Atlantic subtropical cyclone forms; severe weather season in U.S. underway
A rare weather event is underway in the South Atlantic Ocean, where the basin's 7th recorded tropical or subtropical cyclone of all-time has formed. An area of disturbed weather (Invest 90Q) off the coast of Brazil, near 30S 48W, attained a well-defined surface circulation, top wind speeds of tropical depression strength (35 mph), a warm core in the bottom portion of the atmosphere, and a cold core aloft last night. If this storm had been in the North Atlantic, there is a good chance it would have been named Subtropical Depression One. However, tropical and subtropical storms are so rare in the South Atlantic that there is no official naming of depressions or storms done. The cyclone had top winds of at least 35 mph as seen on an ASCAT pass at 7:02 am EST this morning (Figure 2), and satellite estimates of the storm's intensity topped out at 40 mph (minimum subtropical storms strength) last night. This morning, the satellite estimates are showing that the system has weakened to a 35 mph tropical depression. There is some moderate wind shear interfering with development, and sea surface temperatures are about 25°C, which is about 1°C below what is typically needed to support a tropical storm. The storm is headed eastward out to sea, and is not a threat to any land areas. The models show the storm will lose its tropical characteristics and get absorbed by a frontal system by Saturday.
Figure 1. Afternoon visible satellite image of the Brazilian Invest 90Q.
Figure 2. Satellite-measured winds from ASCAT clearly show the circulation of the cyclone in this pass from 7:02 am EST on March 10, 2010. Top winds as seen be ASCAT were 30 knots (35 mph), just below the 40 mph needed for it to be a tropical storm. Image credit: NOAA/NESDIS/ORA.
Brazil has had only one landfalling tropical cyclone in its history, Cyclone Catarina of March 2004. Catarina is one of only six known tropical or subtropical cyclones to form in the South Atlantic, and the only one to reach hurricane strength. Tropical cyclones rarely form in the South Atlantic Ocean, due to strong upper-level wind shear, cool water temperatures, and the lack of an initial disturbance to get things spinning (no African waves or Intertropical Convergence Zone exist in the proper locations in the South Atlantic to help spawn tropical storms). Today's storm is located close to where Catarina formed.
Severe weather season begins
It's March, and that means severe weather season will get underway in earnest for the Midwest U.S., and powerful spring storm systems draw warm, moist air from the Gulf of Mexico northward, to collide with cold, dry air from Canada. It's been a quiet early season, with only 42 tornadoes reported thus far this year (as of Sunday), compared to a normal 70 - 100 twisters. There was only one tornado in the U.S. in February, in a San Joaquin Valley oilfield in California two weekends ago. A year ago, there were 36 February tornadoes, and the year's deadliest tornado occurred on Feb. 10, 2009, in Lone Grove, Oklahoma, where eight people died in a storm with winds estimated at 170 mph. But thanks to a very wet winter and a continued active jet stream pattern that will pull strong storms through the Midwestern U.S. this month, expect at least an average March for severe weather. NOAA's Storm Prediction Center is forecasting a "slight" chance of severe weather across a large portion of the Mississippi Valley today, in association with a strong cold front that will be plowing through the region. Strong thuderstorms capable of generating damaging winds and large hail should develop along the front from southeast Kansas through eastern Oklahoma into NE Texas by middle/late afternoon. The storms should consolidate into broken bands and move into Missouri and and Arkansas by early evening. Isolated tornadoes are also possible in the entire "slight" risk area.
Figure 3. Severe weather forecast for today from the NOAA Storm Prediction Center.
Hurricane Hugo talk
I'm presenting a talk to a class at the University of Michigan this morning on my 1989 flight through Hurricane Hugo. You can listen in live starting at about 10:10 - 10:15 am EST by pointing your browser to http://samson.lecturetools.org/. You'll need to have Apple Quicktime installed. If all goes well, the talk will be recorded and you can view it later, as well.
Jeff Masters
Reader Comments
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I gotta tell ya, I am looking at everything Shreveport has put out this afternoon and nothing says anything about a tornado being on the ground or a confirmed sighting. Where exactly are you getting this?
That sux. We refuse to do anything that is dependent on Microsoft's code. Period.
I haven't seen a nado warning that goes beyond the usual doppler radar indicated with a "could be".
Show us, please?
COUNTIES WILL EXPIRE AT 415 PM CST...
THE WARNING HAS BEEN ALLOWED TO EXPIRE.
I don't want to be difficult, but people with seizure disorders can have an episode if they watch a blinking light too long. They try to avoid them if possible.
I don't believe that for a second. As credible as a triple-digit dewpoint from a broken PWS in the summer...
(j/k, Gro)
NWUS54 KBMX 102207
LSRBMX
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BIRMINGHAM AL
407 PM CST WED MAR 10 2010
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0405 PM FUNNEL CLOUD 2 SW TALLADEGA 33.41N 86.12W
03/10/2010 TALLADEGA AL TRAINED SPOTTER
FUNNEL CLOUD SPOTTED ALONG HWY 275 AND RENFROE ROAD
Nice little image of the feature off Brazil.
very interesting
are the parallels to 2004 anymore abvious?
That strikes me as pretty weird...but whatever. Why would they even risk surfing the internet then if anything that flashes (and there are a lot of things on the internet that do) could give them a seizure?
I don't think it's that big of a deal. I'm not going to abuse that capability. Nothing's going to blink unless it's really urgent.
As far as I can tell there are no significant correlations between south and north Atlantic hurricane activity.
YO! Have you ever known me to be difficult?? LOL
SPC TORNADO AND SEVERE THUNDERSTORM REPORTS
UNOFFICIAL - FOR OFFICIAL REPORTS, SEE PUBLICATION 'STORM DATA'
FOR 06CST WED MAR 10 2010 THRU 16CST WED MAR 10 2010
EVENT LOCATION REMARKS (CST)TIME
.....TORNADO REPORTS..........TORNADO REPORTS..........TORNADO REPORTS.....
NONE REPORTED
I kinda figure there wasn't, I was referring to the parallels between 2004 and 2010 so far
hurricane list, south atlantic storm, etc
Ah just coincidence lol.
Link
NWUS54 KBMX 102223
LSRBMX
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BIRMINGHAM AL
423 PM CST WED MAR 10 2010
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0356 PM FLOOD LOCUST FORK 33.91N 86.62W
03/10/2010 BLOUNT AL LAW ENFORCEMENT
ONE FOOT OF WATER FLOWING OVER DEAVER WALKER RD
(click for full size)
NWUS54 KSHV 102228
LSRSHV
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SHREVEPORT LA
428 PM CST WED MAR 10 2010
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0348 PM FUNNEL CLOUD TEXARKANA 33.44N 94.07W
03/10/2010 BOWIE TX EMERGENCY MNGR
FUNNEL CLOUD REPORTED ON THE NORTHWEST SIDE OF TEXARKANA.
&&
Look who's back! Hey P451. The action starts and your back.
Hey, Hydrus. Good one! ;)
Yup. CAPE = 2600.
(click for full size...reduced just for jeffs and his inept explorer. Poor jeffs.)
NWUS54 KSHV 102237
LSRSHV
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SHREVEPORT LA
437 PM CST WED MAR 10 2010
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0430 PM HAIL DOMINO 33.25N 94.11W
03/10/2010 E1.75 INCH CASS TX EMERGENCY MNGR
GOLFBALL SIZED HAIL REPORTED ALONG THE EAST SIDE OF LAKE
WRIGHT PATMAN NEAR DOMINO.
THE NATIONAL WEATHER SERVICE HAS ISSUED SEVERE THUNDERSTORM WATCH
23 IN EFFECT UNTIL 10 PM CST THIS EVENING FOR THE FOLLOWING AREAS
IN KANSAS THIS WATCH INCLUDES 3 COUNTIES
IN SOUTHEAST KANSAS
BOURBON CHEROKEE CRAWFORD
IN MISSOURI THIS WATCH INCLUDES 34 COUNTIES
IN CENTRAL MISSOURI
BENTON CAMDEN HICKORY
MARIES MILLER MORGAN
PHELPS PULASKI ST. CLAIR
IN SOUTH CENTRAL MISSOURI
DENT HOWELL OREGON
SHANNON TEXAS
IN SOUTHWEST MISSOURI
BARRY BARTON CEDAR
CHRISTIAN DADE DALLAS
DOUGLAS GREENE JASPER
LACLEDE LAWRENCE MCDONALD
NEWTON OZARK POLK
STONE TANEY VERNON
WEBSTER WRIGHT
So far, just a classic super-cell (mostly) hail-only event. So far...not sure how much more it will turn into...
Many of the severe t-storm warnings have included no mention of dangerous winds...some do, though.
... THE NATIONAL WEATHER SERVICE IN WICHITA HAS ISSUED A SIGNIFICANT WEATHER ADVISORY FOR CHAUTAUQUA AND COWLEY COUNTIES...
AT 444 PM CST... NATIONAL WEATHER SERVICE METEOROLOGISTS WERE TRACKING STRONG THUNDERSTORMS ALONG A LINE EXTENDING FROM CHILOCCO TO HARDY TO 17 MILES SOUTH OF GRAINOLA... AND MOVING NORTHEAST AT 40 MPH.
PENNY TO NICKEL SIZE HAIL... AND WINDS TO 50 MPH ARE EXPECTED WITH THESE STORMS.
BE PREPARED TO TAKE SHELTER IN THE EVENT THESE STORMS INTENSIFY AND BECOME SEVERE, OR A WARNING IS ISSUED BY THE NATIONAL WEATHER SERVICE.
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