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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Hmm, a frontal storm exploding within the centre of another frontal storm while the first one expands and weakens. We've seen this occurring at least once earlier this winter.
the Azores High was pretty strong 2006
and that helped the SST were below average
Quoting Chicklit:
GOLFBALL TO HEN EGG SIZE HAIL REPORTED.
ahhh...you're right.
I suppose that is to clarify they weren't robin-sized eggs.
Or ostrich...ouch.
Action: Quote | Ignore User
how would you like football basketball beachball size hail
lol
You said it
lol..
Or it was the cause of the SSTs...stronger trade winds, more evaporative cooling of SST.
Winds have almost everything to do with SST variation in the MDR.
My guess is there are plenty from there.
Did something happen? Explosions somewhere?
And, I thought you were from central or south America, no?
804
WHXX04 KWBC 110138
CHGQLM
ATTENTION...NATIONAL HURRICANE CENTER
NCEP COUPLED GFDL HURRICANE MODEL FORECAST MADE FOR
TROPICAL STORM INVEST 90Q
INITIAL TIME 18Z MAR 10
DISCLAIMER ... THIS INFORMATION IS PROVIDED AS GUIDANCE. IT
REQUIRES INTERPRETATION BY HURRICANE SPECIALISTS AND SHOULD
NOT BE CONSIDERED AS A FINAL PRODUCT. PLEASE SEE THE TPC/NHC
OFFICIAL FORECAST.
FORECAST STORM POSITION
HOUR LATITUDE LONGITUDE HEADING/SPEED(KT)
0 -29.8 46.7 100./ 6.0
6 -29.7 46.1 86./ 5.4
12 -30.2 45.6 133./ 6.4
18 -31.0 44.4 124./13.4
24 -32.0 43.0 125./15.8
30 -32.9 41.4 120./15.3
36 -33.8 39.5 115./19.0
42 -35.2 36.7 117./26.7
48 -37.2 33.4 121./33.2
54 -39.7 29.7 124./38.1
60 -42.7 25.2 123./44.7
STORM DISSIPATED AT 60 HRS AT THE ABOVE PSN
Unobtrusive and appropriately applied.
But, when you do, it will catch my attention.
I like it, if appropriately applied.
Share the same concerns as others on abuse.
Not worried about you.
Were you able find any research that is not simply number of sunspots?
I don't listen to others, other than to trigger a "ok, I'll look."
Just seeking the facts.
Listening to others doesn't cut it. I verify.
All science, not just climatologists.
Bedtime.
is this all you ever post about???
Tropical Disturbance Advisory Number NINE
DEPRESSION SUR TERRE. FORMER HUBERT (13-20092010)
10:00 AM Réunion March 11 2010
====================================
At 6:00 AM UTC, Overland Depression, Former Hubert (998 hPa) located at 20.5S 48.1E has 10 minute sustained winds of 35 knots with gusts of 50 knots. The storm is reported as moving northwest at 3 knots.
Dvorak Intensity:
Gale-Force Winds
=================
within the center
Near Gale-Force Winds
=====================
120 NM from the center extending up to 280 NM in the northeast quadrant
Forecast and Intensity
=====================
12 HRS: 20.8S 46.1E - (Depression sur terre)
24 HRS: 22.0S 44.6E - (Depression sur terre)
48 HRS: 24.7S 41.6E - 20 knots (Perturbation Tropicale)
72 HRS: 24.6S 38.8E - 20 knots (Perturbation Tropicale)
Additional Information
=======================
According to multispectral satellite imagery, Former Cyclone Hubert still shows a rather good configuration with convection wrapping around the low level center.
System should maintain a general westward then southwestward track on the northwestern edge of the subtropical high pressures. Therefore, it is expected to remain overland for the next 24 hours and go out overseas with a very weak circulation. If it happens, potential for re-intensification appears to be poor due to increasing northwestserly shear. This forecast is based on the most availble numerical weather prediction models.
Which earns you an iggy. And yes I'm a scientist
And then there are beachballs. Ouch.....
Tropical Disturbance Advisory #3
TROPICAL DEPRESSION 14F
18:00 PM FST March 11 2010
======================================
A TROPICAL CYCLONE ALERT IS NOW IN FORCE FOR WALLIS AND FUTUNA.
A STRONG WIND WARNING IS NOW IN FORCE FOR WALLIS AND FUTUNA.
At 6:00 AM UTC, Tropical Depression 14 (1002 hPa) located at 11.0S 174.7W has 10 minute sustained winds of 20 knots. Position POOR based on hourly GMS/GOES enhanced infrared imagery with animation. The depression is reported as moving west-southwest at 7 knots.
Organization gradually improving. Primary bands to east and west consolidating and beginning to wrap around low level circulation center. Convection along both bands cooling. Low level circulation lows exposed to southwest of low level circulation center in last visible imagery due to southwest shear. System lies in a diffluent environment. Sea surface temperature is around 30C. Outflow good to east and north, developing elsewhere. System steered west southwest by northeast deep layer mean flow.
Dvorak analysis based on 0.35 wrap on LOG10 spiral yielding DT 2.0
Dvorak Intensity: T2.0/2.0/D1.0/24HRS
Global models agree on west southwest track and intensification.
Forecast and Intensity
========================
12 HRS: 11.3S 175.9W - 25 knots (Tropical Depression)
24 HRS: 11.9S 177.2W - 30 knots (Tropical Depression)
48 HRS: 14.0S 179.2W - 50 knots (CAT 2)
The Next Tropical Disturbance Advisory On TD 14F Will Be Issued At Around 14:30 PM UTC...
But I kept getting blanks in the radar, and the storm track arrows didn't show. Anyone else having a problem? It wasn't just Little Rock's radar. Same problem at other cities.
Tropical Disturbance Summary
TROPICAL DEPRESSION 13F
18:00 PM FST March 11 2010
===================================
At 6:00 AM UTC, Tropical Depression 13 (998 hPa) located at 14.5S 168.5E is reported as slowly moving. Position FAIR based on infrared/visible imagery with animation and peripheral observations. Sea surface temperature is around 30C.
Convection remains persistent in the last 12 hours. Organization remains fairly good. System lies along a monsoon trough and under an upper ridge, in low to moderate shear environment. Global models have picked up the system and moves it westward over the next 24-48 hours with some intensification.
Potential for this system to form into a significant tropical cyclone within the next 24-48 hours is LOW TO MODERATE.
well Im gonna tell you now that insulting someone is not a good way to try to get them to agree with you, quack
Southern hemisphere is heating up, they haven't had a storm in around 20 days
Yeah...it's the same problem on the Mobile,AL and Red Bay,FL. radars. Appears to be on all of them.
Ike- are ya floating yet? it only hold eleven inches! we can see the old pollen lines on ours.
PhatKat- yep the radars were blanking out last night. Very frustrating.
They canceled the flash flood watch west of me. Still under one here but...it ain't happening.
I had .22 inches of rain yesterday. I'll go look at today's total...so far.
I noticed the dogwood trees in town are blooming. Spring is here:)
We're at 0.10. Just a sweet, breezy, overcast morning.
LOL...don't need 4.44...or what's left of my yard doesn't.
Doing fine this morning.
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