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 MrstormX:
Wowza, not too shabby.





is that a eye on the rader?
Member Since: May 21, 2006 Posts: 5091 Comments: 115069
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i think we can say 92L is now RIP
Member Since: May 21, 2006 Posts: 5091 Comments: 115069
Wowza, not too shabby.

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Quoting Tazmanian:
has any one noted that the ITCZ is really poping with t-storms tonight even no nothing march will come out of them




I GUSS NOT
Member Since: May 21, 2006 Posts: 5091 Comments: 115069
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1517. j2008
Well I'm out for the night, got school in the morning.
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Quoting MrstormX:
Weakening Flag : ON

According to ADT, so the raw T# shouldn't be taken to seriously.


Why would this have a weakening flag? Does that mean this is weaker than at 11 PM? How?

I should learn more about the Dvorak technique...
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1515. JLPR2
Quoting MiamiHurricanes09:
At one point the raw T-number from ADT reached T4.2. That's as high as I remember it reaching though, that's still a category 1 though.


I knew I wasn't nuts. XD
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Quoting AussieStorm:



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has any one noted that the ITCZ is really poping with t-storms tonight even no nothing march will come out of them
Member Since: May 21, 2006 Posts: 5091 Comments: 115069
1512. angiest

Quoting MrstormX:
Weakening Flag : ON

According to ADT, so the raw T# shouldn't be taken to seriously.
But sometimes that flag is spurious.
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Weakening Flag : ON

According to ADT, so the raw T# shouldn't be taken to seriously.
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Quoting NCHurricane2009:


Well...actually you can point them to Gert...she may actually pull this off and become a hurricane...she is already looking suspicious I gather from my feelings and some of the comments here.

She isn't a hurricane yet...but her chances are certainly growing by the developments we have been seeing in the last few hours...
I agree.This reminds me of Shary part two.
Member Since: August 14, 2010 Posts: 10 Comments: 16964
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Quoting MrstormX:
I think the center just came into frame, no eye from what I can tell. Just the foundation needed for one.



I guess we have a strong tropical storm on our hands then right now...interesting....
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1507. j2008
Quoting MrstormX:
I think the center just came into frame, no eye from what I can tell. Just the foundation needed for one.


Not quite into view but almost. Should be in the next few minuets.
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Quoting JLPR2:


Really, I remember seeing them close or at hurricane strength and posted here.
At one point the raw T-number from ADT reached T4.2. That's as high as I remember it reaching though, that's still a category 1 though.
Member Since: September 2, 2009 Posts: 130 Comments: 21193
1504. xcool


nam .
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has any one noted that the ITCZ is really poping with t-storms tonight even no nothing march will come out of them
Member Since: May 21, 2006 Posts: 5091 Comments: 115069
I think the center just came into frame, no eye from what I can tell. Just the foundation needed for one.

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Quoting CybrTeddy:
CI# /Pressure/ Vmax
2.5 /1004.7mb/ 35.0kt


Final T# Adj T# Raw T#
2.1 2.6 3.7

Raw T has really cranked up on Gert, now almost to hurricane according just to the RAW T.


What is a 3.7? How close to hurricane?

WOW...is this really developing quickly or what?!
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Quoting pottery:

www.brohavwx.com is a site in Barbados with links to Barbados radar, lightening strikes etc.
Very good.
If you want to see ex-93L go by there....


Hi Pottery, I remember he used to post some here...hope he returns, I liked his post. Hope you get your rain :)
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00z GFS at 36 hours below. The AOI north of HispaƱola right now can be noted as the kink in the 1014mb isobar northeast of eastern Cuba, ex-93L is the low pressure system in the eastern Caribbean, and the AEW currently emerging over water can be noted as the 1011mb south of the Cape Verde islands. Keep in mind, that the previous GFS run developed/intensified this AEW into a hurricane so let's see if we start to develop some consistency.

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1
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1497. JLPR2
Quoting extreme236:


Satellite estimates for Emily topped out at T3.0-3.5 which is 45-55kts. Gert does apppear to be pulling something...


Really, I remember seeing them close or at hurricane strength and posted here.
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Quoting MiamiHurricanes09:
Very compact tropical cyclone.

Gert seems to be pulling the wool over our eyes.I wouldn't be surprised if he becomes our first hurricane of the season.
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1495. angiest

Quoting NCHurricane2009:


I don't know....that center looks like its just outside of 240 km...and it looks "eyeish"...Gert is impressing me minute by minute here....
I wouldn't trust it that far out.  Is that a doppler? Can it do BV and SRV?
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Quoting washingtonian115:
I see idiots still saying we won't have a hurricane this season.I point my finger at them and laugh.What?.They want another 05?.Maybe that will satisfy them sadly.


Well...actually you can point them to Gert...she may actually pull this off and become a hurricane...she is already looking suspicious I gather from my feelings and some of the comments here.

She isn't a hurricane yet...but her chances are certainly growing by the developments we have been seeing in the last few hours...
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1493. JLPR2
Quoting washingtonian115:
Lol when was that?.That was one major mistake.


When Emily blew up south of PR.
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sorry if this posts come out twice.

CI# /Pressure/ Vmax
2.5 /1004.7mb/ 35.0kt


Final T# Adj T# Raw T#
2.1 2.6 3.7

Raw T has really cranked up on Gert, now almost to hurricane according just to the RAW T.
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1491. Gearsts
Quoting MrstormX:


The only problem is that the CV season has started.
You know what i mean.
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The more I look at it...the radar images might actually be fuzzy at that range due to poor reflectivity.
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Quoting JLPR2:


This is the year of misleading TCs, remember the satellites estimates saying Emily was a hurricane while it was barely a tropical cyclone?
Lol when was that?.That was one major mistake.
Member Since: August 14, 2010 Posts: 10 Comments: 16964
Quoting JLPR2:


This is the year of misleading TCs, remember the satellites estimates saying Emily was a hurricane while it was barely a tropical cyclone?


Satellite estimates for Emily topped out at T3.0-3.5 which is 45-55kts. Gert does apppear to be pulling something...
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Very compact tropical cyclone.

Member Since: September 2, 2009 Posts: 130 Comments: 21193
1486. JLPR2
Quoting CybrTeddy:


According to microwave imagery, it is a developing eyewall.. meaning that Gert is probably at least a 60 mph TS at this time. We don't have a recon in there to confirm that, but when recon went in they found a 45 mph TS when the Satellite images said it was only a 35 mph depression.. leads me to suspect this is stronger than the satellite imagery is thinking.


This is the year of misleading TCs, remember the satellites estimates saying Emily was a hurricane while it was barely a tropical cyclone?
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I see idiots still saying we won't have a hurricane this season.I point my finger at them and laugh.What?.They want another 05?.Maybe that will satisfy them sadly.
Member Since: August 14, 2010 Posts: 10 Comments: 16964
Quoting MrstormX:
Another fresh one:


I don't know....that center looks like its just outside of 240 km...and it looks "eyeish"...Gert is impressing me minute by minute here....
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Another fresh one:
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At 9pm the BWS said Gert9s closest point of approach to Bermuda will be 61 nm to the east at 2pm tomorrow [Aug.15]. It is now 185 nm south south-east of Bermuda.

Forecaster Jeff Torgerson said, Rain and showers are expected to amount to up to 1-3 inches potentially across the area, with heavier amounts toward the east, while seas/SE swells are not expected to reach over 9 feet at the peak, with a relatively short-lived development of the storm to this point.

The wind forecast again, is not so much based on model data (consistent in holding generally light and backing winds over the Island), but on the storm track and intensity forecast by NHC.

Strongest winds of 25-35 knots with gusts to 45 knots are expected over the eastern marine area, while the Bermuda forecast holds moderate to strong winds, with gust to gale force.

Gusts are expected to be strongest in and around heavier shower and thunderstorm activity, which, again is most likely to the east of the Island.
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Quoting CybrTeddy:


According to microwave imagery, it is a developing eyewall.. meaning that Gert is probably at least a 60 mph TS at this time. We don't have a recon in there to confirm that, but when recon went in they found a 45 mph TS when the Satellite images said it was only a 35 mph depression.. leads me to suspect this is stronger than the satellite imagery is thinking.


I was thinking the same when reading the 11 PM NHC discussion...they said the 45 mph winds afternoon recon measured were stronger than Dvorak satellite intensity estimates would suggest...and those winds were measured HOURS AGO...The NHC is being conservative here I think this evening.

And it is known infrared satellite intensity estimates can be off with small storms. Why just last year we had this issue with Hurricane Shary....they upgraded it because of its Microwave appaerance...Marco 2008 was really small and sat. intensity estimates were too low as well...

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Quoting 19N81W:
well cyber because you said it I will let it rest...see you nov 31st...


See you then, heck by then judging by this season we might be watching for post-season tropical cyclones.
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1479. 19N81W
well cyber because you said it I will let it rest...see you nov 31st...
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Quoting MrstormX:
Fresh radar image; 2 minutes old:



I am glad we are blogging with all this technology and information available...imagine trying to have a discussion like this back in the good ol' days...

Hmmm...a ship in the open ocean reported some bad weather and looks suspicious....we'll dispatch recon to it....we'll wait and see a few hours in the meantime....
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Quoting MrstormX:


I doubt it is a true eye, but radar should show us what is going on very soon.


According to microwave imagery, it is a developing eyewall.. meaning that Gert is probably at least a 60 mph TS at this time. We don't have a recon in there to confirm that, but when recon went in they found a 45 mph TS when the Satellite images said it was only a 35 mph depression.. leads me to suspect this is stronger than the satellite imagery is thinking.
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model alert! 00z gfs is coming out!
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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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