Tropical Depression Six arrives

By: Dr. Jeff Masters , 5:14 PM GMT on August 22, 2010

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Tropical Storm Tropical Depression Six is here, but it will not be a threat to land for at least the next five days. Tropical Depression Six is a classic "Cape Verdes"-type storm common during the peak part of hurricane season. Cape Verdes-type storms are so named because they form from tropical waves that come off the coast of Africa and pass near the Cape Verdes Islands just west of Africa. Cape Verdes hurricanes are the largest and most dangerous types of hurricane in the Atlantic, since they spend a long time over water have and have of opportunity to reach full maturity. Tropical Depression Six has a ways to go before it becomes a hurricane, as the storm is embedded in a strong easterly flow of wind courtesy of the African Monsoon that is generating a moderately high 15 - 20 knots of wind shear. There is also a tropical disturbance to the northeast of TD 6 that is sucking away some moisture and is interfering with the storm's circulation. Sea Surface Temperatures (SSTs) are a warm 28°C, and the storm is embedded in a moist environment, so wind shear is the primary inhibiting factor for development. The strong east winds imparting the shear are keeping any heavy thunderstorms from developing on the east side of the center of circulation, which is exposed to view in satellite imagery (Figure 1.)


Figure 1. Afternoon satellite image of Tropical Depression Six.

Forecast for Tropical Depression Six
A ridge of high pressure will force Tropical Depression Six to the west-northwest for the next five days, and the system should increase its forward speed from its current 10 mph to 15 mph by Monday night. A powerful trough of low pressure over the mid-Atlantic Ocean will begin to pull Tropical Depression Six more to the northwest late this week, and the storm should pass well to the northeast of the Lesser Antilles Islands. It remains to be seen, however, it this trough will be strong enough to fully recurve Tropical Depression Six out to sea. The GFS predicts that Tropical Depression Six may pass close to Bermuda about eight days from now, and it is also possible that Tropical Depression Six could eventually hit the U.S. East Coast 9 - 15 days from now. However, we have no skill in making these sort of ultra-long range forecasts, and the long-range fate of TD 6 is uncertain.

Elsewhere in the tropics
The ECMWF and NOGAPS models are predicting formation of a tropical depression off the coast of Africa 3 - 4 days from now.

Jeff Masters

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2381. KEEPEROFTHEGATE (Mod)
time for zzzzz

be back around 6 am for 7 am update
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Quoting xcool:
she off forecast points .wnw


yeah shes south of it
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Quoting claire4385:


So does that mean that I'm about to have some strong winds?


Possibly.. people been reporting that with these storms that been moving through the area and maybe towards u..
Member Since: August 15, 2008 Posts: 0 Comments: 2133
2378. xcool
she off forecast points .wnw
Member Since: September 26, 2009 Posts: 2 Comments: 15684
2374. yup
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Quoting claire4385:


So does that mean that I'm about to have some strong winds?


If I am not mistaken the faint green line in front of the storms is the wind..almost to lafayette..if its still there lol
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So does that mean that I'm about to have some strong winds?
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Quoting RuBRNded:


as a disater responder, take it all with a grain of salt. ike, katrina, dennis are good examples.



I remember hurricane Floyd missing a trough, when all the models said would curve him out to sea. The East Coast met his aquantance with flooding and some damage. I hope no one is taking this storm lightly. If the trough does dip down far enough and steer Danielle out to sea then we can take a sigh of relief but until that happens, we still need to conitnue to watch her track ect....jmo
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Quoting KoritheMan:


I agree with this.

as a nobody, i concur.
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Looks like this GFS run is a harmless recurve, not even affecting Bermuda, aside for some big waves. I have it out to 150 and it's at 33N 57W moving N/NNE.
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RuBRNded..

I hear ya and I know about that.. I hope its a fish storm but it is too early to say at the moment.. But even if it is a fish storm we still have the rest of the season til deal with until its over.. But we will see!
Member Since: August 15, 2008 Posts: 0 Comments: 2133
2370. Thaale
144 hours:
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Quoting BahaHurican:
Last post before I head to bed.

I'm seeing a lot of pple posting, "I'm not believing the models; I'm not trusting that Nward turn; What if???" and so on.

I recall that same level of skepticism with storms like Bertha and Bill and Florence 2006 - 2008. From those experiences I learned that 3 times out of four when the models say it's going to recurve before the CONUS, they're on target. Since the potential curve situation is still 5+ days out, we may not see the kinds of signs that we want to see, yet. But NHC's proficiency in forecasting these types of storms has improved a lot even since 2005.

In the 1/4 instance, like Ike, NHC has usually been able to make a call re an unexpected move within 3 - 4 days. And the models usually pick it up within the 5 day period.

Despite the fact that these tools are not infallible, the models, especially in concensus, are are remarkably good tool for determining track of storms. That doesn't mean we shouldn't stick around to ensure that the "out to sea" track verifies; it does mean that the skepticism about track can be belayed until, say, Wednesday. So far it looks like Danielle is moving more or less as expected [I didn't say EXACTLY]. I think there's a good likelihood the recurve track will verify, and if not, we'll likely be aware of major differences by Wednesday...

Good night to all.

Excellent, hahu. HAGN
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Quoting BahaHurican:
Last post before I head to bed.

I'm seeing a lot of pple posting, "I'm not believing the models; I'm not trusting that Nward turn; What if???" and so on.

I recall that same level of skepticism with storms like Bertha and Bill and Florence 2006 - 2008. From those experiences I learned that 3 times out of four when the models say it's going to recurve before the CONUS, they're on target. Since the potential curve situation is still 5+ days out, we may not see the kinds of signs that we want to see, yet. But NHC's proficiency in forecasting these types of storms has improved a lot even since 2005.

In the 1/4 instance, like Ike, NHC has usually been able to make a call re an unexpected move within 3 - 4 days. And the models usually pick it up within the 5 day period.

Despite the fact that these tools are not infallible, the models, especially in concensus, are are remarkably good tool for determining track of storms. That doesn't mean we shouldn't stick around to ensure that the "out to sea" track verifies; it does mean that the skepticism about track can be belayed until, say, Wednesday. So far it looks like Danielle is moving more or less as expected [I didn't say EXACTLY]. I think there's a good likelihood the recurve track will verify, and if not, we'll likely be aware of major differences by Wednesday...

Good night to all.


I agree with this.
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Good Stuff xcool....the regularly updated graphics are just about as good as TampaSpin's animated, time-lapsed video he posted 4-5 hours ago. Keep them comin'!!!!!
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not in ref to fish, but where what when
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Last post before I head to bed.

I'm seeing a lot of pple posting, "I'm not believing the models; I'm not trusting that Nward turn; What if???" and so on.

I recall that same level of skepticism with storms like Bertha and Bill and Florence 2006 - 2008. From those experiences I learned that 3 times out of four when the models say it's going to recurve before the CONUS, they're on target. Since the potential curve situation is still 5+ days out, we may not see the kinds of signs that we want to see, yet. But NHC's proficiency in forecasting these types of storms has improved a lot even since 2005.

In the 1/4 instance, like Ike, NHC has usually been able to make a call re an unexpected move within 3 - 4 days. And the models usually pick it up within the 5 day period.

Despite the fact that these tools are not infallible, the models, especially in concensus, are are remarkably good tool for determining track of storms. That doesn't mean we shouldn't stick around to ensure that the "out to sea" track verifies; it does mean that the skepticism about track can be belayed until, say, Wednesday. So far it looks like Danielle is moving more or less as expected [I didn't say EXACTLY]. I think there's a good likelihood the recurve track will verify, and if not, we'll likely be aware of major differences by Wednesday...

Good night to all.
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Quoting FLPandhandleJG:
Idk y some ppl saying its a fish storm when it hasn't happen yet.. Idk if there trying to predict it or what.. But thats foolishness in my book.. Until it goes straight North and east then yes u can declare it.. Right now, its not a fish storm yet.. JMO

PS: I want it to be a fish storm though.. ;)


as a disater responder, take it all with a grain of salt. ike, katrina, dennis are good examples.
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Quoting KEEPEROFTHEGATE:



south of track?
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2362. Thaale
120 hours:
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Quoting atmoaggie:
Well, I have broken ranks and started calling them Orca storms.


Oh sure... then one will turn into shore..and I will get blamed :) Like the snow in Florida.. or the rain in Macon...
Can't we just call it a Hurricane?


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2360. xcool
atmoaggie lolol
Member Since: September 26, 2009 Posts: 2 Comments: 15684
2359. xcool
Member Since: September 26, 2009 Posts: 2 Comments: 15684
Quoting atmoaggie:
Took a little longer to speed up than they initially thought it would...


Ok. Just as long as she not running late for the trough-train. Thanks.
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Idk y some ppl saying its a fish storm when it hasn't happen yet.. Idk if there trying to predict it or what.. But thats foolishness in my book.. Until it goes straight North and east then yes u can declare it.. Right now, its not a fish storm yet.. JMO

PS: I want it to be a fish storm though.. ;)
Member Since: August 15, 2008 Posts: 0 Comments: 2133
2356. KEEPEROFTHEGATE (Mod)
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Quoting Orcasystems:


Jason just needs to Focus :)
Well, I have broken ranks and started calling them Orca storms.
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Quoting atmoaggie:
Glad I'm not working on a transatlantic Gulf to Europe, ship! That's gotta be extra fun, sometimes.


rowboat?
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Quoting xcool:
[GFS 72 hour]
Glad I'm not working on a transatlantic Gulf to Europe, ship! That's gotta be extra fun, sometimes.
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Quoting Orcasystems:


Jason just needs to Focus :)


good luck on that 1, he's on the fish storm only march
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Models have it up to a CAT4 now.



AOI

AOI

AOI

AOI

AOI

TS BUSTED FORECAST ALIBI
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Quoting btwntx08:

hits bermuda raw fish for a yr no joke


Jason just needs to Focus :)
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2349. will45
if GFS doesnt change she gonna be well east of Bermuda on this run. its out to 90 hrs on my update
Member Since: July 18, 2009 Posts: 1 Comments: 994
2348. xcool
Member Since: September 26, 2009 Posts: 2 Comments: 15684
Quoting Barefootontherocks:


That's interesting, atmo.
Timing? The 8 pm Friday dot is not as far out (N and W) as the 2 pm Thursday dot was.
Took a little longer to speed up than they initially thought it would...
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Quoting washingtonian115:
and im from the state of Washington
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2344. Thaale
84 hours:
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Quoting atmoaggie:
No great big changes here...



That's interesting, atmo.
Timing? The 8 pm Friday dot is not as far out (N and W) as the 2 pm Thursday dot was.
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Quoting washingtonian115:
I'am not beliving what the models say at this moment in time.Maybe in another three days when it is closer to land where the hurricane hunters can fly in it,and give us real data.



I agree here. If you notice the models change so much and the forecast track changes as well. We are not out of the warning area by far. Lets see if the two troughs ahead of Danielle, recurve her out to sea. One poster had a good point, the time will make all the difference. Who's to say Danielle won't slow down or stall. She's moving nw and should move wnw. I'm kind of skeptical about this one.jmo
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Quoting truecajun:


i guess they didn't put them up yet?? but it was definitely significant. it was the same eery howl i remember from andrew, lili, and gustav. it lasted for only 10 minutes, though
Significant in that there are trees down? Or just minor branches?

It will only show at SPC if there were gusts strong enough to cause damage, or measured at 60 mph (? I think) or better.

No doubt you got some winds (had some in Covington, too), but maybe not quite of the severe variety?
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Quoting neonlazer:
850mb and 700mb Vorticity are excellent...500mb is pretty good..but i think the 200mb vorticity is hurting it.
It looks almost absent.
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2338. JRRP
Quoting jason2010xxxx:
STILL A FISH STORM

no kidding
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Quoting neonlazer:
850mb and 700mb Vorticity are excellent...500mb is pretty good..but i think the 200mb vorticity is hurting it.


Most tropical cyclones don't have 200 mb circulations. So that's pretty much irrelevant.
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Quoting Hurricanes101:


well it being a 50mph TS that is not much of a surprise


Well if the convection keeps up like it is now..i would think we would have a hurricane by lunch..(but thats just my humble noobish opinion lol)
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The most common names I see on this blog are Destin,Jeff,Rob,and Tom.Is there any reasoning behind that?.Anyway I think the trof will come because I will feel it here in D.C.Our high on wesnday will only be 77 degress.
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Quoting neonlazer:
850mb and 700mb Vorticity are excellent...500mb is pretty good..but i think the 200mb vorticity is hurting it.


well it being a 50mph TS that is not much of a surprise
Member Since: March 10, 2010 Posts: 1 Comments: 7874

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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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