Little change to TD 7; 93L may develop off the coast of Africa

By: Dr. Jeff Masters , 1:57 PM GMT on August 10, 2012

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Tropical Depression Seven continues westward across the central tropical Atlantic with little change in appearance. Looking remarkably like the tropical depression that became Tropical Storm Ernesto last week, TD 7 has a limited region of heavy thunderstorms, as seen on satellite loops. A large amount of dry air to the west and north is visible on water vapor satellite loops, and this dry air is interfering with TD 7's heavy thunderstorms. Wind shear is a light 5 - 10 knots, which is favorable for intensification. Ocean temperatures are 26.5°C, which is a bit on the cool side, but these temperatures are 0.5° warmer than on Thursday. Winds at the Middle Atlantic buoy 41041 peaked at 29 mph, gusting to 38 mph, at 1:50 am EDT this Friday morning, when the center of TD 7 passed about 40 miles to the south. TD 7 will pass about 60 miles south of buoy 41040 near midnight tonight. The first hurricane hunter mission into TD 7 is scheduled for Saturday morning.


Figure 1. Morning satellite image of TD 7.

Forecast for TD 7
TD 7 formed about 400 miles east-northeast of where Ernesto became a tropical depression, as seen on our wundermap. Atmospheric and oceanic conditions are currently quite similar to what Ernesto experienced, and I expect TD 7 will struggle with dry air like Ernesto did. The SHIPS model predicts that shear will remain light through tonight, then rise to the moderate range on Saturday, when the storm will encounter upper-level southwesterly winds associated with a trough of low pressure. However, ocean temperatures will warm to 28°C, which may partially counteract the increase in shear, as far as maintaining a favorable environment for development. Dry air and shear may be significant enough to destroy TD 7 on Sunday, as predicted by the GFS and ECMWF models. These models tried to kill off Ernesto in a similar situation last week, so I am inclined to believe TD 7 will survive for the coming five days, but struggle. The official NHC forecast of a 45 mph tropical storm moving through the Lesser Antilles Islands Saturday night and Sunday is a reasonable one.


Figure 2. Morning satellite image of Invest 93L.

93L
A strong tropical wave in the far Eastern Atlantic that emerged off the coast of Africa Thursday night was designated Invest 93L by NHC. In their 8 am Tropical Weather Outlook, NHC gave 93L a 50% chance of becoming a tropical depression by Sunday morning. Satellite loops show a pronounced spin to the atmosphere at mid levels, but little in the way of heavy thunderstorm activity. The latest Saharan Air Layer Analysis from the University of Wisconsin shows that while the atmosphere immediately surrounding the disturbance is moist, there is a large area of dry air from the Sahara to the west and north. This dry air will be a significant impediment to development during the coming week. The ECMWF model shows some weak development of 93L over the coming week, and predicts a general west-northwesterly track. The storm may be something Bermuda needs to be concerned about in eight or so days.

I'll have a new post this afternoon.

Jeff Masters

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Quoting washingtonian115:
2012 also had a lot of recurves for a La nina year..

Could you please share your ability to time-travel? ;)
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Quoting floridaboy14:
another mexico storm -__- man this season so far is a snooze. where are the beautiful cape verdes?

Still waiting... u have to realize that the cape verdes season is just starting so there is still plenty of time to have the big fish storms hopefully... give it time
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Quoting hydrus:
If we went from a La-Nina to the current ENSO neutral phase, how is it this years hurricane season has been an El-Nino since day one.? There were plenty of re-curves in 1995 La-Nina.
2010 also had a lot of recurves for a La nina year..
Member Since: August 14, 2010 Posts: 10 Comments: 17810
Quoting AussieStorm:


Is this it??


AussieStorm: Yes that is the report that backed his article. With this I can find his artcle but I really like this report. Thanks very much. After I have a chance to digest it more I will probably have some questions to bounce off of you and others.
Member Since: August 1, 2012 Posts: 0 Comments: 255
Quoting LargoFl:
..I dont know but two different models have it in the gulf this weekend..we have to be careful now

oy-vey...I hate the home grown ones
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Quoting floridaboy14:
another mexico storm -__- man this season so far is a snooze. where are the beautiful cape verdes?


A snooze? I got 18 inches of rain from Debby.
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Quoting luvtogolf:


Moving faster at 23mph. It had better hold on or else the llc is going to get exposed.


I might go against Dr. M then; if it speeds up any further, GFS might be right and it could degenerate into an open wave. Here is the most recent GFS run which BTW does re-develop the remnants of Ernesto.

Link
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Quoting hurricanehanna:

is that the wave or ex-Flo?
..I dont know but two different models have it in the gulf this weekend..we have to be careful now
Member Since: August 6, 2011 Posts: 4 Comments: 42085
Quoting floridaboy14:
another mexico storm -__- man this season so far is a snooze. where are the beautiful cape verdes?
They'll be coming Mah Booooi.Our first is right by Africa now.
Member Since: August 14, 2010 Posts: 10 Comments: 17810
Quoting sar2401:


23 mph is way too fast to maintain itself as an organized system, even with favorable conditions. Has there ever been a TD that reverted back to an invest?


Yes, in fact it happened yesterday with TD7
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Quoting LargoFl:
LOL, i just killed a million of them all trying to go higher on my house..ants know something we dont and can feel it coming..always listen to the signals nature gives huh

I used to joke about my dogs "nesting" before a storm was coming...animals do sense things before us.
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Quoting Levi32:


It's been an El Nino season from Day 1.

During such seasons there is a greater chance of recurving storms out to sea because of developments occurring farther north, but there is also often a greater potential for developments close to land that end up making landfalls. This year has the pattern to favor in-close developments as well as those in the middle of the ocean that El Nino seasons are known for.
If we went from a La-Nina to the current ENSO neutral phase, how is it this years hurricane season has been an El-Nino since day one.? There were plenty of re-curves in 1995 La-Nina.
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..............................Yep..something IN the gulf this weekend
Member Since: August 6, 2011 Posts: 4 Comments: 42085
Quoting LargoFl:
..........................................oh oh...something IS going into the gulf after it crosses florida according to the Nam model

is that the wave or ex-Flo?
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another mexico storm -__- man this season so far is a snooze. where are the beautiful cape verdes?
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Thanks again for those totals on the Katrina comments. Link is awesome thanks AussieStorm.
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107. VR46L
Quoting washingtonian115:
93L still lacks sufficient convection it needs to blow up some more of it if it wants to be tagged T.D 8.


Cheers appreciate your opinion Wash
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..........................................oh oh...something IS going into the gulf after it crosses florida according to the Nam model
Member Since: August 6, 2011 Posts: 4 Comments: 42085
Quoting sar2401:


Where? I don't see nothing. :)


I fixed it... here is the link
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Quoting SLU:


yep. watches should be posted for the islands at 11am

I said the same thing on the last page (#1)

Quoting kmanislander:


We don't want any confusion now do we ? LOL

true but that is why there is a W in front lol

Quoting kmanislander:


Can't have two on the blog as "Kman". We don't want to get credit, or crow, for each other's forecasts !

true

Quoting sar2401:


"Wukman"? :) Seriously, what would you prefer we use?

WKC thats what I had before and I wouldn't mind going back to that
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Quoting ncstorm:
I will say I still have those ants in my front yard..DOOM!!!!
LOL, i just killed a million of them all trying to go higher on my house..ants know something we dont and can feel it coming..always listen to the signals nature gives huh
Member Since: August 6, 2011 Posts: 4 Comments: 42085
Quoting VR46L:


I think 93L looks better

and it's pressure is 1004 and 30knots wind source tropical atlantic


Whereas this ones pressure is 1009 and same strength of wind
93L still lacks sufficient convection it needs to blow up some more of it if it wants to be tagged T.D 8.
Member Since: August 14, 2010 Posts: 10 Comments: 17810
Quoting AussieStorm:


Here is all of August 2005. Not many comments for each blog.


I honestly didnt know there was a blog..I only came here at the beginning for Dr. Masters updates..I would have registered before 2006 if I had known..
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Quoting WxLogic:
...TROPICAL DEPRESSION MOVING FASTER TO THE WEST...INTERESTS IN THE WINDWARD AND LEEWARD ISLANDS SHOULD MONITOR THE PROGRESS THIS SYSTEM...
11:00 AM AST Fri Aug 10
Location: 13.7°N 49.5°W
Moving: W at 23 mph
Min pressure: 1009 mb
Max sustained: 35 mph


Moving faster at 23mph. It had better hold on or else the llc is going to get exposed.
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Kman: What is your opinion on future track and intensity for TD7?
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central.carib.looks.more.favorable.than.when.ernest o.passed.
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95. SLU
...TROPICAL DEPRESSION MOVING FASTER TO THE WEST...INTERESTS IN THE WINDWARD AND LEEWARD ISLANDS SHOULD MONITOR THE PROGRESS THIS SYSTEM...
------------------------------------------------- -------------------------------

11:00 AM AST Fri Aug 10
Location: 13.7°N 49.5°W
Moving: W at 23 mph
Min pressure: 1009 mb
Max sustained: 35 mph
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I will say I still have those ants in my front yard..DOOM!!!!
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Have to run out now. Back later.
Member Since: August 19, 2006 Posts: 0 Comments: 15948
Quoting kmanislander:


Can't have two on the blog as "Kman". We don't want to get credit, or crow, for each other's forecasts !


I'm gonna call everyone from the caymans Kman from now on just to confuse you :p

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Quoting ncstorm:


I dont think we ever got that far..5000 and some change might have been the most I have ever seen the blog get up to..the DOC will change the blog with regular updates when there is an approaching storm..however keeping up with comments, thats another whole story..


Here is all of August 2005. Not many comments for each blog.
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Quoting washingtonian115:
Seems more likely all though T.D 7 has a head start.I need them both to be named so they can move the hell out of the way and make room for Isaac.


I think 93L looks better

and it's pressure is 1004 and 30knots wind source tropical atlantic


Whereas this ones pressure is 1009 and same strength of wind
Member Since: Posts: Comments:
...TROPICAL DEPRESSION MOVING FASTER TO THE WEST...INTERESTS IN THE WINDWARD AND LEEWARD ISLANDS SHOULD MONITOR THE PROGRESS THIS SYSTEM...
11:00 AM AST Fri Aug 10
Location: 13.7°N 49.5°W
Moving: W at 23 mph
Min pressure: 1009 mb
Max sustained: 35 mph
Member Since: Posts: Comments:
Quoting sar2401:


"Wukman"? :) Seriously, what would you prefer we use?


I think Wunderkid should decide that one.
Member Since: August 19, 2006 Posts: 0 Comments: 15948
Quoting weathermanwannabe:


I know...........Lol. Hope things are going well and hoping that you and the family are spared this year from any destructive storms in the Caiman Islands but the recent steering patterns must be a little bit disturbing to see................ :)


Indeed, It's a long way to the middle of October and the secondary peak. These Caribbean cruisers may eventually get it just right with the conditions and then there will be big problems in the basin and perhaps points North.
Member Since: August 19, 2006 Posts: 0 Comments: 15948
Quoting weathermanwannabe:


Alrighty then.........."WKman".....

lol ok then I can go with that

Quoting sar2401:


If it's down to 10 knots by 60W, then I'll start getting a LOT more interested. :)

I expecting it will drop to 10-15kt and yes I'm expecting it
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ULL associated with that tropical wave in the Central Caribbean that's been blowing up convection this morning has now got increasing storms to the NW of the ball of convection too; which has come on fairly suddenly. Was going to get my day going, wanted to check the satellite image one more time; and was impressed at how it come on so suddenly. Levi, if your still around, any thoughts?
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Quoting wunderkidcayman:

hey Kman well I remember when people use to call me WKC and kinda wish we can go back to that I don't really like it when people call me kid cause I get mixed up if there calling me a kid or my handle name


Can't have two on the blog as "Kman". We don't want to get credit, or crow, for each other's forecasts !
Member Since: August 19, 2006 Posts: 0 Comments: 15948
Quoting kmanislander:


We don't want any confusion now do we ? LOL


I know...........Lol. Hope things are going well and hoping that you and the family are spared this year from any destructive storms in the Caiman Islands but the recent steering patterns must be a little bit disturbing to see................ :)
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Quoting DavidHOUTX:


This one went quite a long way too!

I find it interesting that Ike never degenerated back into a tropical storm all of his life until his final destination here in the U.S.Even after tangling with Cuba which is known for rapidly weakening/dissipating systems.
Member Since: August 14, 2010 Posts: 10 Comments: 17810
ok, thanks Levi. so, in short, you think home grown storms could be more a threat. I was just asking becuase a lot of forecasters said we are in enso but heading into el nino.

Also, not to focus only on Florida, but do you see this year as possibly having tracks similar to 2004 and 2005? If I am recalling correctly, 2004 was a weak to moderate el nino and 2005 was an enso season.

Thanks Levi.
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Quoting weathermanwannabe:


Alrighty then.........."WKman".....


We don't want any confusion now do we ? LOL
Member Since: August 19, 2006 Posts: 0 Comments: 15948
77. SLU
Quoting WxLogic:


Was about to mention that... is trying to get some heavier convection around its center. Well see how it fairs the rest of the day.


yep. watches should be posted for the islands at 11am
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Quoting kmanislander:


Good morning

Given that for many years I have always been referred to on this blog as "Kman" I wonder if you could find another abbreviation for Wunderkidcayman ?? :-)

TIA

hey Kman well I remember when people use to call me WKC and kinda wish we can go back to that I don't really like it when people call me kid cause I get mixed up if there calling me a kid or my handle name
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Quoting kmanislander:


Good morning

Given that for many years I have always been referred to on this blog as "Kman" I wonder if you could find another abbreviation for Wunderkidcayman ?? :-)

TIA


Alrighty then.........."WKman".....
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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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