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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Whoa, that's some nasty dry air.

Member Since: September 2, 2009 Posts: 130 Comments: 21194
Hmmmm,

After some soul searching, the best projected path for Danielle should cover from NE Texas to the NE US, includin Bermuda! Talk about a large cone, you can't go wrong with that! LOL.

JK.
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Quoting PcolaDan:
Ike, I'm beginning to think I may want a copy of your list. ;)
Alphabetical? or chronology? lol
Member Since: August 11, 2010 Posts: 0 Comments: 895
1179. IKE
Quoting PcolaDan:
Ike, I'm beginning to think I may want a copy of your list. ;)


PM me...I'll gladly give it to you.
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Still here... just lurking... ;)
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Why don't redundent quotes count as violating community standards?
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1176. scott39
Quoting NCHurricane2009:


Whic trough is first and which is second. Do you mean the first trough is the one over the NE US currently, and the second trough is the bigger one over the NW US currently? That's what I am seeing.
Yep
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1175. Relix
Quoting Thundercloud01221991:


Tropical Storm Fay


And there you prove my point. When that happened Fay was a 70mph Storm, borderline Hurricane. That can be expected. Danielle is but a 40mph storm at the moment undergoing gradual intensification. There's no eye forming.
Member Since: August 3, 2006 Posts: 0 Comments: 2725
1174. Ryuujin
I don't care if IKE reads this or not, as I can only assume that "Poof" is his clever word for putting a user on ignore. But I will postulate this for the rest of the blog that seems to wish to have a level headed discussion of both tropical formation and forecasting.

If the GFS has the storm curving out to sea continually, or having a sharp right hand turn (Ala Alex earlier in the year) because of it's known cold bias, then why are we all 100% sure of it's projected path for Danielle now? I mean, I'm not hoping this thing hits the CONUS or any of the leeward islands, or bermuda. I'm simply not sticking my head in the sand as to the possibility that a computer generated model could be wrong. What do you all think?
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Quoting Relix:


People NO. Eyes DO NOT develop over tropical storms. It's some Cat 1 or 2 Hurricanes and you can't see a defined eye. It's just lots of convection.
If I remember correctly Ike had an eye when it was a 85mph storm.
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Quoting NCHurricane2009:


I concur. Still wondering, does anyone know which trough over the US is supposed to curve Danielle NW. I am voting its the trough over the northwestern US right now. Just want to watch which trough should do it.
I'm not sure where the trofs are located now, but I know 1 will come through and curve it towards the NW. Then a second more amplified trof will come in and recurve it fully. The question is, if these trofs will be amplified enough to dig south enough and recurve the cyclone before ridging sets in and sends the cyclone generally westward.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Ike, I'm beginning to think I may want a copy of your list. ;)
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1170. xcool



mmmm
Member Since: September 26, 2009 Posts: 2 Comments: 15684
Quoting scott39:
First trof miss. Second, We better hope so!


Whic trough is first and which is second. Do you mean the first trough is the one over the NE US currently, and the second trough is the bigger one over the NW US currently? That's what I am seeing.
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1168. scott39
Quoting markot:
nogaps turns it west.
How many time have you posted West in 24 Hours?
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1167. markot
nogaps turns it west.
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1166. IKE
Quoting TropicalAnalystwx13:


Ouch!


And all I was doing was teasing. I surrender with him.
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Isn't every storm a lil different.. Y does every1 seem the storm will slow down.. If i remember right, I thought there were some hurricanes still had some fast speed..? am I right or is it mostly all storms slow down.. Isnt it mostly all hurricanes slow down.. or depends on the development and the environment of the storm..
Member Since: August 15, 2008 Posts: 0 Comments: 2133
Quoting Relix:


Can you please point to me a TS with an eye? I would think maybe, just maybe, a 70MPH could have one, but a storm like Danielle at the moment wouldn't. Also, no, it's not undergoing RI. It's definitely strengthening a lot but it still has long ways before become a Hurricane. 24 hours at best, but 18 sounds reasonable.


Tropical Storm Fay
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Quoting Relix:


Can you please point to me a TS with an eye? I would think maybe, just maybe, a 70MPH could have one, but a storm like Danielle at the moment wouldn't. Also, no, it's not undergoing RI. It's definitely strengthening a lot but it still has long ways before become a Hurricane. 24 hours at best, but 18 sounds reasonable.


I would be more like its strengthening at an average pace, say 45 to 50 mph winds by 11 PM EDT. Easterly shear is inhibiting outflow and much storm activity east of center.
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Quoting IKE:


It was a joke. I'm gonna end this....

poof! 103 and counting.


Ouch!
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1161. Ryuujin
Quoting IKE:


It was a joke. I'm gonna end this....

poof!


I'm just saying. And my questions are valid ones. Why would you ignore what I'm saying?
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http://www.ndbc.noaa.gov/station_page.php?station=13008 Try this Ply
Member Since: August 11, 2010 Posts: 0 Comments: 895
Quoting IKE:
Not sure if this was ever posted, but the 12Z NOGAPS takes it to Bermuda...Link


A lot of flopping at the end as expected. Time will tell, the future trough is the key.
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Quoting Relix:


People NO. Eyes DO NOT develop over tropical storms. It's some Cat 1 or 2 Hurricanes and you can't see a defined eye. It's just lots of convection.


eyes can form in stronger tropical storms
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1157. scott39
Quoting NCHurricane2009:


I concur. Still wondering, does anyone know which trough over the US is supposed to curve Danielle NW. I am voting its the trough over the northwestern US right now. Just want to watch which trough should do it.
First trof miss. Second, We better hope so!
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Quoting Thundercloud01221991:


1. I have seen TSs with an eye
2. Who knows if this is undergoing RI right now and is a hurricane
I've seen TS's with eyes too, but not TS's with winds of 40mph.

Well it isn't. There is nothing to prove that this is developing an eye nor undergoing rapid intensification. It is organizing nicely and may become a hurricane in 72 hours or so, but it isn't undergoing RI or currently hurricane.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
1155. Relix
Quoting Thundercloud01221991:


1. I have seen TSs with an eye
2. Who knows if this is undergoing RI right now and is a hurricane


Can you please point to me a TS with an eye? I would think maybe, just maybe, a 70MPH could have one, but a storm like Danielle at the moment wouldn't. Also, no, it's not undergoing RI. It's definitely strengthening a lot but it still has long ways before become a Hurricane. 24 hours at best, but 18 sounds reasonable.
Member Since: August 3, 2006 Posts: 0 Comments: 2725
Quoting CybrTeddy:


Doubt it, convection is still on the very edge of the convection. Could go up to 45 at 11.


Convection is still on the very edge of the convection?
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1152. xcool


dry
Member Since: September 26, 2009 Posts: 2 Comments: 15684
Quoting MiamiHurricanes09:
UW-CIMSS thinks Danielle is a 47kt TS.

Chances are that Danielle gets bumped to 45mph at 11p.m.



I concur. Still wondering, does anyone know which trough over the US is supposed to curve Danielle NW. I am voting its the trough over the northwestern US right now. Just want to watch which trough should do it.
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Quoting Ameister12:

Lol!
Quoting plywoodstatenative:
Any buoy's in the area?
there is one at 15n 38w but I dont know how to post a link!
Member Since: August 11, 2010 Posts: 0 Comments: 895
1149. IKE
Not sure if this was ever posted, but the 12Z NOGAPS takes it to Bermuda...Link
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the system will get stronger in a hurry and will slow down rather than speed up consequently missing the weakness in the ridge and not re-curving florida must keep an eye on this one
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Quoting Relix:


People NO. Eyes DO NOT develop over tropical storms. It's some Cat 1 or 2 Hurricanes and you can't see a defined eye. It's just lots of convection.


1. I have seen TSs with an eye
2. Who knows if this is undergoing RI right now and is a hurricane
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1146. markot
nogaps turns danielle west......
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1145. HadesGodWyvern (Mod)
Japan Meteorological Agency
Tropical Cyclone Advisory #6
TROPICAL DEPRESSION 07
6:00 AM JST August 23 2010
===============================

SUBJECT: Tropical Depression In The South China Sea

At 21:00 PM UTC, Tropical Depression (996 hPa) located at 16.0N 111.8E has 10 minute sustained winds of 30 knots with gusts of 45 knots. The depression is reported as moving west at 8 knots

Dvorak Intensity:

Forecast and Intensity
=======================
24 HRS: 17.9N 108.5E - 40 knots (CAT 1/Tropical Storm)
Member Since: May 24, 2006 Posts: 51 Comments: 45743
1144. scott39
Quoting FLdewey:

What do I win?
Quoting FLdewey:

What do I win?
Try again
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1142. Relix
Quoting Thundercloud01221991:
are you sure we do not have a rapidly developing eye.... or at least eyewall look at the center of the IR here




plus this is very intense convection


People NO. Eyes DO NOT develop over tropical storms. It's some Cat 1 or 2 Hurricanes and you can't see a defined eye. It's just lots of convection.
Member Since: August 3, 2006 Posts: 0 Comments: 2725
1141. xcool
CybrTeddy .50k.at 11pm
Member Since: September 26, 2009 Posts: 2 Comments: 15684
Tiny system, but small systems have a habit of being nasty. What does the size of a system comparable to its strength do for a recurve or not
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Quoting xcool:


hurricane soon.imo


Doubt it, convection is still on the very edge of the convection. Could go up to 45 at 11.
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Quoting Thundercloud01221991:
are you sure we do not have a rapidly developing eye.... or at least eyewall look at the center of the IR here




plus this is very intense convection
Something is there.
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Quoting doorman79:
lol its gone on the last frame, she must have dyed it!!!

Lol!
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Any buoy's in the area?
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1134. xcool


hurricane soon.imo
Member Since: September 26, 2009 Posts: 2 Comments: 15684
Member Since: August 15, 2008 Posts: 0 Comments: 2133

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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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