Tropical Depression Seven forms

By: Dr. Jeff Masters , 2:25 PM GMT on August 14, 2011

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The latest in our unusual number of weak tropical cyclones this season, Tropical Depression Seven, has formed to the southeast of Bermuda. Unless you live in Bermuda, TD 7 is not going to be a concern. Radar out of Bermuda shows an area of rain on the northern side of TD 7 beginning to approach the island, and rain from the storm will likely affect the island tonight and on Monday. TD 7 is not well-organized, and has only limited heavy thunderstorms, as seen on visible satellite images. While wind shear is a low 5 - 10 knots, dry air surrounds TD 7, and is keeping the storm from intensifying. None of the computer models foresee that TD 7 will ever become more than a weak tropical storm.


Figure 1. Morning satellite image of TD 7.

92L
TD 7 isn't the only system Bermuda needs to watch, Invest 92L is a day behind it, and will follow a path very similar to TD 7's. The disturbance will pass close to Bermuda on Tuesday, bringing the island a second round of tropical rains. However, Invest 92L is very disorganized, as seen on recent visible satellite loops. Dry air and close proximity to TD 7 will likely keep 92L from showing significant development over the next two days, with NHC giving the system just a 30% chance of developing into a tropical depression by Tuesday morning.

Elsewhere in the tropics
The disturbance midway between the Lesser Antilles Islands and the coast of Africa we've been tracking over the past few days, Invest 93L, has fallen apart and is no longer a threat to develop. This system will need to be watched once it enters the Caribbean later this week, though. None of the reliable models for predicting tropical cyclone formation predict development of this system or any new disturbances over the coming week.

Jeff Masters

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Quoting presslord:


Thanks for all the moral support....off to prepare a Thermos full of Bloody Mary....


Good Luck. Dad to Dad, my nervousness and prayers will be with you, friend.
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74. KBH
Quoting weatherh98:


93l

Where can I find info on how the invests are named? for tracking purposes it would seem logical at the beginning of the season to start at 1 and continue upwards; then it would be possible to see which invest developed into nothing, a storm or hurricane,.. just my 2 cents worth
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Quoting WhereIsTheStorm:
Current conditions at Charleston, South Carolina according to wunderground.

Conditions
Pressure
29.89 in
Visibility
10.0 miles
Clouds
Few 2000 ft
Scattered Clouds 25000 ft

Conditions at the moment are pretty good. Wind gusts are at 0 to 1.

There may be some clouds building in later today as they are expecting thunderstorms; but they will cancel the flight if visibility drops below 10 miles.


Thanks for all the moral support....off to prepare a Thermos full of Bloody Mary....
Member Since: August 13, 2007 Posts: 0 Comments: 10492
Quoting cloudburst2011:
so to put it simple the tropics are QUIET for the middle of august and we still havent had our first HURRICANE of the 2011 season yet..the united states mainland with the way the A/B high is positioned now looks like they will get away another year without a HURRICANE strike...which is terrific news...


We have two more weeks left in August plus September & October. That Texas heatwave won't last forever & it is causing dry air to sink downward over part of the Atlantic basin. Late season storms often form in the GOM & Western Carribean so Troughs will pull these TOWARDS the US. Every hurricane season is different & you never know what you are going to get. The Atlantic basin is extremely warm so there is a lot to fuel storms with.
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Current conditions at Charleston, South Carolina according to wunderground.

Conditions
Pressure
29.89 in
Visibility
10.0 miles
Clouds
Few 2000 ft
Scattered Clouds 25000 ft

Conditions at the moment are pretty good. Wind gusts are at 0 to 1.

There may be some clouds building in later today as they are expecting thunderstorms; but they will cancel the flight if visibility drops below 10 miles.
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Quoting Orcasystems:


We seem to have forgot summer.. and have stayed in a nice warm spring it seems. Average is 20-22 everyday... nice and warm, no really hot days at all.
we had a good run with the heat the east coast had been cooler and wet as well like you looks like summer chose to hang out over the centre of the country this season for the most part but like i said we only got about 6 weeks left then we get into the fall then winter pattern
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Quoting KBH:

If ex 93L develops again will it likely have the same name '93L' or is it considered a 'new system'?


93l
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Quoting stormpetrol:
ex93L is expanding and looking better all time imo, if no yellow circle at 1 pm cst, then at 7 pm cst if it still looks this good!


if it looks like the taj mahal still check the vorticity thats the only way to tell if its the taj mahal.... it aint the taj mahal
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Quoting presslord:


that it is flown by the Iraqi Air Force is not particularly comforting...

Press, you actually made me laugh with that comment.
Don't forget the binoculars when you go.
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Quoting KEEPEROFTHEGATE:
iam sure the kid will be fine its his passion he has no choice but to be good at it


apparently it is a useful skill for romancing 20 year old girls...
Member Since: August 13, 2007 Posts: 0 Comments: 10492
65. KBH
Quoting AllStar17:
Ex-93L firing off some convection.

If ex 93L develops again will it likely have the same name '93L' or is it considered a 'new system'?
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ex93L is expanding and looking better all time imo, if no yellow circle at 1 pm cst, then at 7 pm cst if it still looks this good!
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Quoting WhereIsTheStorm:


Not to worry, these planes have been in use since 1955.
Link


that it is flown by the Iraqi Air Force is not particularly comforting...
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Quoting WhereIsTheStorm:


Not to worry, these planes have been in use since 1955.
Link


Read this it should help it is the glide ratio for a 172.
Link
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Quoting presslord:



actually...none of this helps at all...but thanks so much for the effort
iam sure the kid will be fine its his passion he has no choice but to be good at it
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27.7n61.2w, 28.2n62.1w have been re-evaluated&altered for TD7's_12pmGMT_ATCF
27.7n61.4w, 28.0n62.2w, 28.1n62.9w are now the most recent positions
Starting at 13August_12pmGMT and ending at 14August_12pmGMT

The westernmost line-segment is the straightline projection

TropicalDepression7's travel-speed was 7.2mph(11.5k/h) on a heading of 279.3degrees(W)
Using straightline projection of the travel-speed&heading derived from the ATCF coordinates spanning the 6hours between 6amGMT then 12pmGMT :
TD.7 was headed toward passage over FlaglerBeach,Florida ~6days7hours from now
(though I wouldn't count on TD.7 to continue moving that slowly)
Copy&paste 27.1n59.4w, 27.4n60.5w, 27.7n61.4w-28.0n62.2w, 28.0n62.2w-28.1n62.9w, bda, komn, 28.0n62.2w-29.4n81.09w into the GreatCircleMapper for more info

TD7's_12pmGMT_ATCF _ & _ 92L's_12pmGMT_ATCF
Starting at 13August_12pmGMT and ending at 14August_12pmGMT

The northernmost grouping of red dots represents TD7's path,
and the southernmost grouping represents 92L's path.

Copy&paste 27.1n59.4w, 27.4n60.5w, 27.7n61.4w-28.0n62.2w, 28.0n62.2w-28.1n62.9w, komn, bda, 19.0n52.0w, 20.3n54.4w, 21.6n56.6w, 22.3n58.0w, 22.8n59.0w into the GreatCircleMapper to start your own map for tinkering with.

The previous mapping (for 14August_6amGMT)
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Quoting presslord:
he flies a '172'....which I think is some sorta Cessna....


Not to worry, these planes have been in use since 1955.
Link
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Quoting WhereIsTheStorm:


Did he neglect to tell you that he has practiced this maneuver with a trained professional in the cockpit? On the other hand, I have seen pictures of successful ocean landing by small craft, if that helps.



actually...none of this helps at all...but thanks so much for the effort
Member Since: August 13, 2007 Posts: 0 Comments: 10492
Quoting presslord:


Oh, no!!! He'll be alone...he soloed at 16....Aussie: Charleston Executive @ Johns Island....he'll apparently be over the ocean....and assures me he can land on the Ocean Course @ Kiawah Island if need be...


Did he neglect to tell you that he has practiced this maneuver with a trained professional in the cockpit? On the other hand, I have seen pictures of successful ocean landing by small craft, if that helps.
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Quoting KEEPEROFTHEGATE:
ITS A RUSH YOU FEEL THAT TINKLING FROM THE TOES ALL THE WAY UP AS THE PLANE STARTS TO DRIVE HEADING STRAIGHT DOWN TOWARDS THE GROUND GETTING EVER CLOSER THEN ENGINE RESTART AND PULL UP TAKE OFF WITH THE GROUND FALLING BEHIND YOU WHAT A RUSH CAN YA INVISION THAT PRESS CAN YA SEE IT


I plan to be too drunk to see it...
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sorry for the caps just making sure press can see it clearly
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Quoting iamajeepmom:


::giggle:: I'm sorry ... but I can just SO feel your pain :) ... don't worry too much, those are trained professionals with him!


ROFL.. don't remind him of that old expression... those who can... do.. those who can't... teach.
Member Since: October 1, 2007 Posts: 81 Comments: 26511
he flies a '172'....which I think is some sorta Cessna....
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Quoting WhereIsTheStorm:


I don't believe you are making presslord feel any better..LOL Press - depending on the size/style of aircraft and of course height at the time of stall, most of your smaller planes can actually glide for short distances, of course I am referring to prop airplanes. Good Luck and relax a little. I watch them do this maneuver all the time around here.
ITS A RUSH YOU FEEL THAT TINKLING FROM THE TOES ALL THE WAY UP AS THE PLANE STARTS TO DRIVE HEADING STRAIGHT DOWN TOWARDS THE GROUND GETTING EVER CLOSER THEN ENGINE RESTART AND PULL UP TAKE OFF WITH THE GROUND FALLING BEHIND YOU WHAT A RUSH CAN YA INVISION THAT PRESS CAN YA SEE IT
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Quoting melwerle:
Hey Press - you ever see that commercial where the Dad is handing the keys to the five year old in the car? Yep...I'm sure that's how you feel right about now. It's a feeling only a parent understands and that commercial hits the nail on the head PERFECTLY.


yup...I love that...
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Quoting KEEPEROFTHEGATE:
1774. KEEPEROFTHEGATE 2:30 PM GMT on August 14, 2011 +0
Quoting Orcasystems:


Did your heatwave finally break KOG?

yes the ex starts on friday heat is done watch it rain for the first week of the ex always does then heat will be back as the kids get ready for school last week of aug first week of sept we only got 6 weeks to go fish before the first night frosts show up
Action: Quote | Modify Comment
Member Since: July 15, 2006 Posts: 108 Comments: 26872


We seem to have forgot summer.. and have stayed in a nice warm spring it seems. Average is 20-22 everyday... nice and warm, no really hot days at all.
Member Since: October 1, 2007 Posts: 81 Comments: 26511
Hey Press - you ever see that commercial where the Dad is handing the keys to the five year old in the car? Yep...I'm sure that's how you feel right about now. It's a feeling only a parent understands and that commercial hits the nail on the head PERFECTLY.
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Quoting iamajeepmom:


::giggle:: I'm sorry ... but I can just SO feel your pain :) ... don't worry too much, those are trained professionals with him!


Oh, no!!! He'll be alone...he soloed at 16....Aussie: Charleston Executive @ Johns Island....he'll apparently be over the ocean....and assures me he can land on the Ocean Course @ Kiawah Island if need be...
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Center under the recent blowup of convection.
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Quoting KEEPEROFTHEGATE:
thats cool press its fun when ya cut the engine and free fall for a bit then try engine restart and level it out again


I don't believe you are making presslord feel any better..LOL Press - depending on the size/style of aircraft and of course height at the time of stall, most of your smaller planes can actually glide for short distances, of course I am referring to prop airplanes. Good Luck and relax a little. I watch them do this maneuver all the time around here.
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Quoting melwerle:


Oh God...I'd be drinking too. Bring Valium.

I have plenty of that, which airport again Press?
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Quoting presslord:


oh God


::giggle:: I'm sorry ... but I can just SO feel your pain :) ... don't worry too much, those are trained professionals with him!
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The global models are not developing 93L before it get to the islands. tend to disagree, because there is a vast improvement in the structure of the system and conditions ahead of the disturbed area are getting better. there is vast area of ocean real estate between the islands and 93L, about 900 miles. i expect the system to get more organised with time,and sooner or later the models will be taking a closer look at the system.
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Quoting presslord:
OK...just spoke to the boy....and, thanks to y'all, managed to sound moderately knowledgeable....he delighted in telling me that today he is practicing 'stalls'....which, I suspect, means exactly what I think it means...........I'll be the guy sitting outside at the airport drinking heavily....


Oh God...I'd be drinking too. Bring Valium.
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Quoting scott39:
IF ex-93L developes into a TD and stays weak in the Caribbean, it will go into CA. IF it becomes stronger, look for a pull to the weakness over the Central/N Gulf Coast.


What weakness
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A pretty long discussion from Stewart, but does say that it looks like TD7 should have a window to strengthen a bit and become yet another name.
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um..if TD7 has turned northwestward, wouldnt that also put the CONUS at risk?
Member Since: August 19, 2006 Posts: 13 Comments: 15745
XX/AOI/XL
MARK
13.33N/50.00W


07L/TD/G/CX
invest 92L TO SE


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Ex-93L firing off some convection.
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33. KBH
looks like 93L is just a rain system for the caribbean, although that much cloud mass is likely to be lots of rain, any idea how much rain is likely?
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Quoting jasblt:
Is this the new hurricane scale they have been talking about using for storms? Or just a tool to add to the SS scale?

Link

Interesting. Thanks for that.
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Quoting KEEPEROFTHEGATE:
thats cool press its fun when ya cut the engine and free fall for a bit then try engine restart and level it out again


oh God
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Quoting stoormfury:
moiture field in tropical wave/ex 93L is expanding,and will continue to grow. both convergence and divergence are getting better around the system. watch out the islanders


At the rat its moving its going to be almost on top of them within 14 hours
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TROPICAL DEPRESSION SEVEN DISCUSSION NUMBER 3
NWS NATIONAL HURRICANE CENTER MIAMI FL AL072011
1100 AM AST SUN AUG 14 2011

DURING THE PAST 6 HOURS...CONVECTION HAS BEGUN TO REDEVELOP OVER AND
SOUTHEAST OF THE LOW-LEVEL CENTER OF THE DEPRESSION IN RESPONSE TO
DECREASING VERTICAL WIND SHEAR AND INCREASING MID-LEVEL MOISTURE.
ALTHOUGH DATA T-NUMBERS HAVE DECREASED TO T1.5 AND T1.0 FROM TAFB
AND SAB...RESPECTIVELY...THE INITIAL INTENSITY REMAINS AT 30 KT
BASED ON SATELLITE CURRENT INTENSITY ESTIMATES OF T2.0/30 KT AND
THE IMPROVED CONVECTIVE ORGANIZATION SINCE THE 12Z SATELLITE FIXES.

WATER VAPOR IMAGERY INDICATES THE DEPRESSION IS MOVING INTO A COL
REGION ON THE NORTH SIDE OF AN UPPER-LEVEL LOW THAT IS LOCATED
ABOUT 150 NMI SOUTHWEST OF THE CYCLONE. AS A RESULT...THE PREVIOUS
WESTERLY VERTICAL SHEAR REGIME IS BEING REPLACED BY A MORE
FAVORABLE SOUTHEASTERLY LOW-SHEAR ENVIRONMENT...WHICH SHOULD FAVOR
THE CONTINUED DEVELOPMENT OF DEEP CONVECTION FOR THE NEXT 12-24
HOURS. THE CYCLONE IS EXPECTED TO REMAIN WITHIN A FAVORABLE
UPPER-LEVEL FLOW ENVIRONMENT FOR THE NEXT 48-60 HOURS...WHICH WOULD
NORMALLY FAVOR SIGNIFICANT INTENSIFICATION. HOWEVER...THERMODYNAMIC
CONDITIONS ARE FORECAST TO BE LESS FAVORABLE AS THE CYCLONE MOVES
OVER SUB-26C SSTS BY 48 HOURS. THESE OUT-OF-PHASE CONDITIONS ARE
EXPECTED TO RESULT IN ONLY MODEST STRENGTHENING. BY DAY 4...THE
POST-TROPICAL CYCLONE IS FORECAST TO BE ABSORBED BY A FRONT. THE
OFFICIAL INTENSITY FORECAST IS SIMILAR TO THE PREVIOUS ADVISORY AND
CLOSELY FOLLOWS A BLEND OF THE SHIPS AND LGEM INTENSITY MODELS.

THE DEPRESSION HAS SLOWED AND MADE AN UNEXPECTED JOG TO THE WEST...
AND THE INITIAL MOTION ESTIMATE IS NOW 285/09. THE TRACK FORECAST
IS LESS STRAIGHTFORWARD THAN THE INTENSITY FORECAST. THE RECENT
WESTWARD JOG IS PROBABLY DUE IN PART TO THE SYSTEM BECOMING MORE
VERTICALLY SHALLOW AFTER THE DEEP CONVECTION WEAKENED EARLIER THIS
MORNING. NOW THAT CONVECTION HAS REDEVELOPED...THE CYCLONE SHOULD
TURN NORTHWESTWARD WITHIN THE NEXT 12 HOURS AS IT COMES UNDER THE
INFLUENCE OF DEEP-LAYER SOUTHEASTERLY STEERING FLOW. BEYOND 12
HOURS...THE TRACK FORECAST BECOMES MORE COMPLICATED. THE 12Z
UPPER-AIR DATA FROM BERMUDA THIS MORNING INDICATES THE MID-LEVEL
FLOW FROM 700-400 MB HAS BACKED AROUND TO THE SOUTH-SOUTHWEST AND
HEIGHTS HAVE FALLEN 40-60 METERS WITHIN THIS LAYER. THIS SUGGESTS
THAT THE SUBTROPICAL RIDGE TO THE NORTH OF THE DEPRESSION HAS
WEAKENED...WHICH SHOULD ALLOW THE SYSTEM TO TURN NORTHWESTWARD OR
EVEN NORTHWARD. HOWEVER...WATER VAPOR IMAGERY INDICATES THAT A
SHORTWAVE TROUGH APPROACHING BERMUDA RAPIDLY FROM THE WEST IS THE
LIKELY CAUSE OF THE EROSION OF THE RIDGE. WITH THE MAIN UPPER-LEVEL
TROUGH STILL OVER THE U.S. OHIO AND TENNESSEE VALLEYS...THE RIDGE
COULD TEMPORARILY BUILD BACK WESTWARD BETWEEN BERMUDA AND THE
DEPRESSION...RESULTING IN A STAIR-STEP TYPE OF MOTION TO THE
NORTHWEST DURING THE NEXT 24 HOURS OR SO. THE MAIN UPPER-LEVEL
TROUGH IS EXPECTED TO LIFT THE CYCLONE QUICKLY TO THE NORTHEAST BY
36-48 HOURS AND TAKE IT ACROSS MUCH COLDER WATER IN 60-72
HOURS...WHICH WILL INDUCE EXTRATROPICAL TRANSITION. THE OFFICIAL
FORECAST TRACK HAS BEEN NUDGED A LITTLE TO THE WEST OF THE PREVIOUS
FORECAST TRACK THROUGH 24 HOURS BASED ON THE MORE WESTWARD INITIAL
POSITION...AND LIES JUST TO THE LEFT OF THE GLOBAL MODEL
CONSENSUS...BUT WELL TO THE EAST OF THE TIGHTLY PACKED BAM MODELS.

AS A RESULT OF THE WESTWARD SHIFT IN THE FORECAST TRACK...WHICH
BRINGS THE CYCLONE CLOSER TO BERMUDA...THE BERMUDA WEATHER SERVICE
HAS ISSUED A TROPICAL STORM WARNING FOR BERMUDA.

FORECAST POSITIONS AND MAX WINDS

INIT 14/1500Z 28.2N 63.2W 30 KT 35 MPH
12H 15/0000Z 29.6N 63.7W 35 KT 40 MPH
24H 15/1200Z 31.8N 63.8W 40 KT 45 MPH
36H 16/0000Z 34.9N 62.4W 45 KT 50 MPH
48H 16/1200Z 38.6N 58.9W 50 KT 60 MPH
72H 17/1200Z 47.0N 49.0W 45 KT 50 MPH...POST-TROP/EXTRATROP
96H 18/1200Z...DISSIPATED

$$
FORECASTER STEWART
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Quoting presslord:
OK...just spoke to the boy....and, thanks to y'all, managed to sound moderately knowledgeable....he delighted in telling me that today he is practicing 'stalls'....which, I suspect, means exactly what I think it means...........I'll be the guy sitting outside at the airport drinking heavily....
thats cool press its fun when ya cut the engine and free fall for a bit then try engine restart and level it out again
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A little change, not supposed to hold at 50kts so long.
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-
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...DEPRESSION MOVING SLOWLY WEST-NORTHWESTWARD BUT EXPECTED TO TURN NORTHWESTWARD TOWARD BERMUDA BY TONIGHT... ...TROPICAL STORM WARNING ISSUED FOR BERMUDA...
11:00 AM AST Sun Aug 14
Location: 28.2°N 63.2°W
Max sustained: 35 mph
Moving: WNW at 7 mph
Min pressure: 1010 mb
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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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