New tropical depression could form off the coast of Africa

By: Dr. Jeff Masters , 1:12 PM GMT on September 25, 2009

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A tropical wave (99L) is located near 15N, 30W, about 300 miles west of the Cape Verdes Islands. This wave has seen an increase in heavy thunderstorm activity this morning, and low-level spiral bands have formed. The system can already be classified as a tropical depression using the satellite-based Dvorak technique. This morning's QuickSCAT pass showed a loose but closed circulation, with top winds of 30 mph in the heaviest thunderstorms. Wind shear is moderate, about 10 - 20 knots. There is a modest amount of dry air to 99L's west that does not appear to be interfering with the storm's organization.


Figure 1. Morning visible satellite image of Invest 99L (left side of image) and a new tropical wave moving off the coast of Africa.

As 99L moves west-northwest over the next two days, sea surface temperatures will cool by 1°C and winds shear will remain in the moderate range. Some dry air may also affect the storm. These conditions give 99L a good chance of forming into a tropical depression, and NHC has given the system a moderate (30 - 50%) chance of developing into a tropical depression by Sunday. By Monday, wind shear will increase to the high range, 20 - 30 knots, and 99L will probably weaken or be torn apart. None of the computer models forecast development of 99L or any other system in the Atlantic over the next seven days.

A new tropical wave with plenty of heavy thunderstorm activity and some spin is moving off the coast of Africa today. This wave is under a moderate amount of wind shear, 10 - 20 knots, and has some potential for development this week as it moves west or west-northwest past the Cape Verdes Islands.

The latest wind shear forecasts from our major computer models show high values of wind shear affecting most of the tropical Atlantic for the next ten days. This is typical for an El Niño year, and it will be difficult for any storms to get to hurricane strength over the next ten days because of the high shear. The latest 16-day GFS forecast predicts wind shear will decline some by the 2nd week of October, though.


Figure 2. Wind shear forecast for Thursday, October 2 at 00 UTC made by last night's 00Z run of the GFS model. Wind shear is expected to be high over most of the tropical Atlantic for the next ten days, including the Caribbean. Wind shear values below 8 m/s (about 15 knots, red colors), are typically needed to support tropical storm formation.

Jeff Masters

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Quoting Patrap:
Dont worry,those Co2 And Co3 and other Man Made gasses were dumping 24/7/365 into Gaia's atmosphere are all scrubbed nightly by the Fairies in yer heads.


No worries...just keep on keeping on...
All's well..no need to worry.

yep all is good don't worry about a thing this is easy
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QuikSCAT weather satellite on last legs

The QuikSCAT weather satellite, which helps forecasters track remote tropical systems, may be on its last legs, U.S. Rep. Ron Klein, D-Boca Raton, said today.

Klein said he received an internal memo from the National Oceanic and Atmospheric Administration, alerting that bearings on the satellite are experiencing increasing friction, making it more difficult for its antenna to turn.

Further, the motor that turns the antenna is starting to grind down, according to a separate memo from NASA. The memo says QuikSCAT is "likely to fail in the next several weeks to months."
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Quoting AussieStorm:

99L is doing good... atm, D-Max is making it look good i suppose


It's not Dmax right now though, is it? I thought that was right around sunrise, maybe I'm wrong :P
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Quoting tornadodude:


ok, gotcha, well I'm done with Climate Change debate for today, thanks for sharing your views, it is always interesting to learn about other's perspectives.

so, what's 99L doing?

99L is doing good... atm, D-Max is making it look good i suppose
Member Since: September 30, 2007 Posts: 9 Comments: 16017
Quoting hydrus:
lol.. You sound as if you had a ranch out there during that time.


LOL. Not back then, unless ranching in a swamp was a good idea.
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Quoting Murko:


LOL. That's the best guess from it's current drift put into reverse back to Pangea.
Quoting Elena85Vet:


He's referring to tectonic plate movement. Even South Dakota had palm trees years ago due to it's more southern latitude. The Colorado Rockies weren't even around then.


ok, gotcha, well I'm done with Climate Change debate for today, thanks for sharing your views, it is always interesting to learn about other's perspectives.

so, what's 99L doing?
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Quoting Elena85Vet:


He's referring to tectonic plate movement. Even South Dakota had palm trees years ago due to it's more southern latitude. The Colorado Rockies weren't even around then.
lol.. You sound as if you had a ranch out there during that time.
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Quoting Elena85Vet:


He's referring to tectonic plate movement. Even South Dakota had palm trees years ago due to it's more southern latitude. The Colorado Rockies weren't even around then.


And the Antarctic has coal.
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Quoting AussieStorm:

I'm a newbie and I've been here for about 4 years... i think.


I am newbie 101...can see things on satellite, found buoy info, wind maps, etc, but beyond that it's a little fuzzy. I know that other components are involved like SST, troughs, shear, etc...I guess things that I am least familiar with are steering, shear and identifying circulation other than just the visible..."oh yeah it's swirling"! LOL
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Quoting tornadodude:


just curious but how on earth do you know where it moved 2m years ago? (floodman might remember) ;)


He's referring to tectonic plate movement. Even South Dakota had palm trees years ago due to it's more southern latitude. The Colorado Rockies weren't even around then.
Member Since: Posts: Comments:
Dont worry,those Co2 And Co3 and other Man Made gasses were dumping 24/7/365 into Gaia's atmosphere are all scrubbed nightly by the Fairies in yer heads.


No worries...just keep on keeping on...
All's well..no need to worry.

Member Since: July 3, 2005 Posts: 434 Comments: 133477
Quoting tornadodude:


just curious but how on earth do you know where it moved 2m years ago? (floodman might remember) ;)


LOL. That's the best guess from it's current drift put into reverse back to Pangea.
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Quoting Murko:


Ice cores recovered so far go back 800,000 years, and there are deeper ones to recover yet. The then southerly Antarctic coast only drifted across the pole about 2m years ago.

But the deepest (oldest) ones cannot tell us what happened within any 500 year period. Those are especially poor at short-term variation.
Back L8R.
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Quoting Murko:


Ice cores recovered so far go back 800,000 years, and there are deeper ones to recover yet. The then southerly Antarctic coast only drifted across the pole about 2m years ago.


just curious but how on earth do you know where it moved 2m years ago? (floodman might remember) ;)
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Quoting Elena85Vet:


Nothing to be ashamed about. Weather is so fluid that anything beyond 10 days makes even the experts newbies at times. There are just levels of newbieness? LOL

I'm a newbie and I've been here for about 4 years... i think.
Member Since: September 30, 2007 Posts: 9 Comments: 16017
Quoting tornadodude:


good morning guys,

ok, I dont want to argue, but the ice cores at most date back to ten thousand years, and the earth is supposedly billions of years old, so they only cover a mere fraction of the earth's existence. also, did you ever think that there is a reason that the ice cores only go back that far?


Ice cores recovered so far go back 800,000 years, and there are deeper ones to recover yet. The then southerly Antarctic coast only drifted across the pole about 2m years ago.
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Quoting AussieStorm:
Just a thought, whats the tornado count this year compared to previous years????


there have been 850 this year, and last year saw 1,691. 2007 saw 1,098. 2006 saw 1,093. the three year average has been 1,297.

SPC
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Quoting 850Realtor:
Thanks WxLogic and LawntonLookers. I have experienced many storms living in the Panhandle, but know nothing about the science involved. I have learned alot from the forums, but am still a newbie. Don't know anything :)


Nothing to be ashamed about. Weather is so fluid that anything beyond 10 days makes even the experts newbies at times. There are just levels of newbieness? LOL
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Quoting tornadodude:


good morning guys,

ok, I dont want to argue, but the ice cores at most date back to ten thousand years, and the earth is supposedly billions of years old, so they only cover a mere fraction of the earth's existence. also, did you ever think that there is a reason that the ice cores only go back that far?

Not to mention that the temporal resolution of ice cores is rather poor. And they cannot tell us much about the last 1000 years, in most cases and they are incapable (usually) of showing us details finer than a few hundred years. So, they are actually not capable of telling us if we have had a temp change in the past that equaled or exceeded that of the last 30 years.

So far, I haven't seen many detailing the temperature about 800 years ago.
Given the temp-then-CO2 order (CO2 lagging temp changes by about 800 years) in the distant past, as evidenced by ice cores, I wonder what the temperature trends were doing about 800 years ago. (Though we were in the medieval warm period then, I think we are undecided as to whether or not that was regional or global).
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Just a thought, whats the tornado count this year compared to previous years????
Member Since: September 30, 2007 Posts: 9 Comments: 16017
Quoting tornadodude:


so isnt it possible that earth is undergoing another "big thaw"? also it is most likely enhanced by humans to a certain degree, but who really knows
It is possible.
Member Since: September 30, 2007 Posts: 9 Comments: 16017
Quoting AussieStorm:

The last big thaw was 18000 years ago, remember the Vikings used to grow food on Greenland and Iceland.


so isnt it possible that earth is undergoing another "big thaw"? also it is most likely enhanced by humans to a certain degree, but who really knows
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Quoting tornadodude:


good morning guys,

ok, I dont want to argue, but the ice cores at most date back to ten thousand years, and the earth is supposedly billions of years old, so they only cover a mere fraction of the earth's existence. also, did you ever think that there is a reason that the ice cores only go back that far?

The last big thaw was about 18000 years ago, remember the Vikings used to grow food on Greenland and Iceland.
Member Since: September 30, 2007 Posts: 9 Comments: 16017
Thanks WxLogic and LawntonLookers. I have experienced many storms living in the Panhandle, but know nothing about the science involved. I have learned alot from the forums, but am still a newbie. Don't know anything :)
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Quoting Murko:
This is a great site for GW proponants and sceptics alike:

http://www.grist.org/article/series/skeptics/

Really, there is good evidence and bad evidence on both sides. What you have to do is look at all the envidence, evaluate it, and figure out who has the most good evidence. If many different ice core samples give similar results for climate over the last 1000s of years, and a few anectodal stories from 1000 years ago give a different account, I know which one I'd believe!

Yeah, well if you want to read the pro-AGW stance and response to common questions written by non-scientists, go for it.
They actually defend Mann's hockey stick proxy reconstruction there...amazing.
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Quoting Murko:
This is a great site for GW proponants and sceptics alike:

http://www.grist.org/article/series/skeptics/

Really, there is good evidence and bad evidence on both sides. What you have to do is look at all the envidence, evaluate it, and figure out who has the most good evidence. If many different ice core samples give similar results for climate over the last 1000s of years, and a few anectodal stories from 1000 years ago give a different account, I know which one I'd believe!


good morning guys,

ok, I dont want to argue, but the ice cores at most date back to ten thousand years, and the earth is supposedly billions of years old, so they only cover a mere fraction of the earth's existence. also, did you ever think that there is a reason that the ice cores only go back that far?
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Quoting AussieStorm:


Thanks, It has been predicted not to be as bad but they didnt predict Wednesdays one so its wait and see I guess.


Some of the stuff in the 'Red dawn, the dust sequel strikes' story sounds like the old Oklahoma Dust Bowl stuff. Let's hope yours is just temporary.
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Quoting tornadofan:
Aussie - best of luck with the potential dust storm.

Quoting Elena85Vet:

Ditto that.
Buy stock in auto, home, and business ventilation filters.

Thanks, It has been predicted not to be as bad but they didnt predict Wednesdays one so its wait and see I guess.
Member Since: September 30, 2007 Posts: 9 Comments: 16017
Quoting tornadofan:


Yummm - fried Spam. Might have to have that for dinner tonight!


As only a poor college student would know. j/k :)
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Quoting tornadofan:
Aussie - best of luck with the potential dust storm.


Ditto that.
Buy stock in auto, home, and business ventilation filters.
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Aussie - best of luck with the potential dust storm.
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Quoting Elena85Vet:


KOG

Is it time to raid the hurricane survival kits?

SPAM sandwiches for everyone? :)


Yummm - fried Spam. Might have to have that for dinner tonight!
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Red dawn, the dust sequel strikes

* From: The Daily Telegraph
* September 26, 2009 12:00AM

Another Red Wednesday unlikely

EVERY asthmatic in NSW was warned to stay inside today amid fears another dust storm will spread across the state and engulf Sydney.

Nervous weather forecasters and health authorities, criticised for being caught off guard by Wednesday's dust storm, said yesterday it was impossible to predict how bad any potential storm would be today. The dust would depend on the strength of westerly winds due to blast eastern NSW this morning in the wake of a cold front.

But the bureau said late yesterday it believed the dust would not be as severe as Wednesday's stunning storm, which turned the entire city and half the state red.

"Big dust storms are very rare and are very difficult to predict," a Bureau of Meteorology spokesman said yesterday. "We'll be monitoring the situation through the night."

Broken Hill, which on Tuesday gave Sydney a preview of what was in store for the city the next morning, was hit by more dust storms yesterday.

Farmers Ruth Sandow, who lives 160km north of Broken Hill, said the dust storms had ripped every shred of vegetation from some properties, leaving paddocks looking like deserts and farmers in the area were finding dozens of dead lambs on their properties, which were totally overwhelmed by the dust and died where they stood when the storm hit.

Both The Asthma Foundation and NSW health were not taking any chances yesterday, issueing a health alert for today
Member Since: September 30, 2007 Posts: 9 Comments: 16017

Dust storm heading towards Sydney


* From: AAP
* September 25, 2009 11:44PM

A DUST storm headed for Sydney is likely to blow in early tomorrow morning.

A cold front originating from South Australia reached Cobar in central NSW, about 10pm (AEST) tonight, a Bureau of Meteorology spokesman said.

Satellite photos indicate an area of dust particles swept up in the storm measures up to 200km wide, a Bureau of Meteorology spokesman said.

The storm will continue to cross from the west of the state to the east overnight, and will possibly reach Sydney around sunrise.

If that is the case visibility in the city will be reduced, the BoM spokesman said, but it's unlikely there will be a repeat of the dramatic scenes witnessed in Sydney on Wednesday morning, when the city was bathed in red, orange and yellow hues..
"The area of dust seems much smaller," the BoM spokesman said.

Visibility is likely to be reduced for a couple of hours, he added.

A dry, partly cloudy day with fresh to strong gusty westerly winds is forecast for Sydney on Saturday, with a top temperature of 21 degrees.

Health authorities are advising asthmatics to avoid exercising outdoors in the morning.

A severe weather warning is forecast for much of eastern NSW, including the Southern Tablelands, Central Tablelands, south coast, the Illawarra and the Hunter district.
Member Since: September 30, 2007 Posts: 9 Comments: 16017
Quoting KEEPEROFTHEGATE:
nice update doc seems as if the rest of the season should be a non issue as the fall pattern takes hold and pretty well finishes the season off


KOG

Is it time to raid the hurricane survival kits?

SPAM sandwiches for everyone? :)
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Quoting Elena85Vet:


That was yesterdays blog.


And today's, it spilled over :)
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Quoting Murko:
This is a great site for GW proponants and sceptics alike:

http://www.grist.org/article/series/skeptics/

Really, there is good evidence and bad evidence on both sides. What you have to do is look at all the envidence, evaluate it, and figure out who has the most good evidence. If many different ice core samples give similar results for climate over the last 1000s of years, and a few anectodal stories from 1000 years ago give a different account, I know which one I'd believe!


That was yesterdays blog.
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nice update doc seems as if the rest of the season should be a non issue as the fall pattern takes hold and pretty well finishes the season off
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Quoting 850Realtor:
Does anyone have an answer to my question from earlier? About reading the wind maps?


Try this link and explans the wind barb if that is what you were asking.

wind barbs
Member Since: Posts: Comments:
This is a great site for GW proponants and sceptics alike:

http://www.grist.org/article/series/skeptics/

Really, there is good evidence and bad evidence on both sides. What you have to do is look at all the envidence, evaluate it, and figure out who has the most good evidence. If many different ice core samples give similar results for climate over the last 1000s of years, and a few anectodal stories from 1000 years ago give a different account, I know which one I'd believe!
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Quoting 850Realtor:
Does anyone have an answer to my question from earlier? About reading the wind maps?


If you look at the QS pass you'll be able to see 20 to 30 kts gusts in TSTM that you were referring... not much to any additional information you can get from it... aside from being able to pick up low level circulation as you might already know.

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Thanks for the update Dr. Masters.

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Quoting PensacolaDoug:
Hey Yonza. Supposedly the Vikings were growing grapes and a few other crops in Greenland during the "Medievil Warm Period". Assuming that is true, that would indicate it was warmer then than the graph you put up would indicate. I want more research on the issue.
Impartial unbiased research. Too much tweaking of the "facts" on both sides.


You can't draw conclusions about global climate from an anecdote about a single region, or even a few regions. You need detailed analysis of proxy climate indicators from around the world. These proxy reconstructions have shown that the Medieval Warm Period (around the time the Vikings are said to have discovered North America) was not as pronounced or as warm as today's warmth.

As for the specific anecdote that Vineland was a warm land where grapes grew wild: as with the Greenland story, Vineland's name was most likely a kind of marketing ploy.

The main problem with a Newfoundland and Labrador (formerly Newfoundland) site is the absence of wild grapes. Still, there is a strong suspicion that what Leif found were only berries, and that he followed the practice of his father in "giving a land a good name so that men would want to go there".

From grist.org
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incredible that we have not had any systems form in the carribean sea this year ????? i hope october will be as quiet as it is now.
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could we have a new TD at 11 AM today ???
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Thx Doc.,,
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Does anyone have an answer to my question from earlier? About reading the wind maps?
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Wishcasting for blog to wake up :p
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Dr. Masters co-founded wunderground in 1995. He flew with the NOAA Hurricane Hunters from 1986-1990. Co-blogging with him: Bob Henson, @bhensonweather

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