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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The 00z dynamic models have shifted east

I was kind of expecting that.
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Quoting DestinJeff:
Check at 50/15 .... north of 15 at 50, recurve in order.

South of 15 at 50, fugitaboutit.


20 60 is another benchmark
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Quoting Bordonaro:

Good. HOWEVER, 75 million people live in the New England-Washington DC corridor, called the "Megalopolis"...


I wonder how the FEMA response would be if something hit DC?
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Quoting Patrap:
00z Early Cycle NHC model tracks
Statistical/Simple Models (CLIPER,BAMs,LBAR,other Statistical Models)




Dynamic Models (More sophisticated models)






LOL one mode run has 135kt
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T3.0=45kts/50MPH

CIMSS ADT usually isn't taken into consideration until the system reaches hurricane status.
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Quoting Dakster:
For all of us on the intensity of Danielle. read what the NHC says:

.THE INTENSITY GUIDANCE HAS
CONTINUED TO SCALE BACK ON THE INTENSIFICATION OF THE CYCLONE.
SLOW STRENGTHENING IS ANTICIPATED FOR MUCH OF THE FORECAST PERIOD
SINCE VERTICAL SHEAR IS CURRENTLY NOT IDEAL...AND SOME DRY AIR
APPEARS TO SURROUND THE SYSTEM. THE STATISTICAL GUIDANCE SEEMS TO
SUGGEST THAT THE VERTICAL SHEAR COULD INCREASE AGAIN AFTER DAY
3...AND THE LGEM DOES NOT EVEN STRENGTHEN THE CYCLONE TO A HURRICANE
DURING THE FORECAST PERIOD.


Interesting... Yet Danielle is definetly intensifying - I wouldn't go with RI yet though. (in MY opinion)


Exactly why you can't always depend on models. What is happening os damn obvious.
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1526. Patrap
Quoting Kristina40:
Yikes Patrap, that intensity model sure took a spike upward.


Indeed.

Food for thought.
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Quoting HurricaneSwirl:


That's just one satellite estimation. But if that one satellite estimation is correct, then yes it is a 60 mph storm. But I think it's too aggressive.

50mph is more likely IMO.
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Quoting palmasdelrio:

Does that mean that it's moving west and not wnw?

If that satellite estimate is correct, (assuming that the 5p.m EDT advisory is also correct), Danielle has been moving towards the WNW.
Member Since: September 2, 2009 Posts: 130 Comments: 21193
Yikes Patrap, that intensity model sure took a spike upward.
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CI MWS MWS MSLP MSLP Saffir-Simpson
Number (Knots) (MPH) (Atlantic) (NW Pacific) Category
1 25 KTS 29 MPH (Approximate)
1.5 25 KTS 29 MPH
2 30 KTS 35 MPH 1009 mb 1000 mb
2.5 35 KTS 40 MPH 1005 mb 997 mb
3 45 KTS 52 MPH 1000 mb 991 mb
3.5 55 KTS 63 MPH 994 mb 984 mb
4 65 KTS 75 MPH 987 mb 976 mb 1 (64-83 KTS)
4.5 77 KTS 89 MPH 979 mb 966 mb 1 (64-83 KTS); 2 (84-96 KTS)
5 90 KTS 104 MPH 970 mb 954 mb 2 (84-96 KTS); 3 (97-113 KTS)
5.5 102 KTS 117 MPH 960 mb 941 mb 3 (97-113 KTS)
6 115 KTS 132 MPH 948 mb 927 mb 4 (114-135 KTS)
6.5 127 KTS 146 MPH 935 mb 914 mb 4 (114-135 KTS)
7 140 KTS 161 MPH 921 mb 898 mb 5 (136+ KTS)
7.5 155 KTS 178 MPH 906 mb 879 mb 5 (136+ KTS)
8 170 KTS 196 MPH 890 mb 858 mb 5 (136+ KTS)

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1520. Patrap
Patrap, dawlin, you're welcome here next time something hits. You know we'll be grilling.

Ill bring the Tony's Chactere's seasoning.

Thanx
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1519. Grothar
Quoting Asta:

AHa- so I could ask you what people asked me after Katrina-- Why do you people live there?
But I won't.. I'll just ask- Well what do you want to share about it- if anything?


It was a beautiful day. Many people were on the beach for so late in the season. There were weather people who knew about the storm, but couldn't get the message out fast enough. The storm moved so quickly that people were all going to the South Shore beaches to watch the enormous waves that were being observed. It hit so quickly they were washed away. It moved quickly over Long Island and went into Rhode Island, where the people on the street in the cities had to be pulled in from 2nd story windows, the flooding was so bad. It then moved into Canada. The old movie actress, Katharine Hepburn was swimming in Long Island Sound when the storm hit and I believe lost her home, or it was badly damaged.

Any time you want to discuss the Civil War, just ask.
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Quoting MiamiHurricanes09:
Lol, no problem.

Does that mean that it's moving west and not wnw?

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OFCI getting close to a major hurricane...says 110mph at 120 hours, 5mph shy of a category 3.

AL, 06, 2010082300, 03, OFCI, 0, 140N, 353W, 40, 0, TD, 34, NEQ, 30, 30, 45, 45,
AL, 06, 2010082300, 03, OFCI, 12, 149N, 376W, 45, 0, TS, 34, NEQ, 37, 37, 59, 45,
AL, 06, 2010082300, 03, OFCI, 24, 159N, 403W, 52, 0, TS, 34, NEQ, 52, 51, 80, 54,
AL, 06, 2010082300, 03, OFCI, 24, 159N, 403W, 52, 0, TS, 50, NEQ, 40, 14, 13, 27,
AL, 06, 2010082300, 03, OFCI, 36, 171N, 431W, 62, 0, TS, 34, NEQ, 73, 66, 95, 74,
AL, 06, 2010082300, 03, OFCI, 36, 171N, 431W, 62, 0, TS, 50, NEQ, 42, 22, 14, 35,
AL, 06, 2010082300, 03, OFCI, 48, 184N, 458W, 69, 0, TS, 34, NEQ, 91, 77, 106, 92,
AL, 06, 2010082300, 03, OFCI, 48, 184N, 458W, 69, 0, TS, 50, NEQ, 46, 32, 18, 42,
AL, 06, 2010082300, 03, OFCI, 60, 197N, 484W, 74, 0, , 34, NEQ, 100, 85, 114, 100,
AL, 06, 2010082300, 03, OFCI, 60, 197N, 484W, 74, 0, , 50, NEQ, 53, 40, 25, 43,
AL, 06, 2010082300, 03, OFCI, 72, 212N, 506W, 78, 0, HU, 34, NEQ, 103, 88, 117, 104,
AL, 06, 2010082300, 03, OFCI, 72, 212N, 506W, 78, 0, HU, 50, NEQ, 57, 43, 28, 43,
AL, 06, 2010082300, 03, OFCI, 84, 226N, 526W, 81, 0, , 34, NEQ, 0, 0, 0, 0,
AL, 06, 2010082300, 03, OFCI, 96, 240N, 544W, 85, 0, HU, 34, NEQ, 0, 0, 0, 0,
AL, 06, 2010082300, 03, OFCI, 108, 253N, 559W, 89, 0, , 34, NEQ, 0, 0, 0, 0,
AL, 06, 2010082300, 03, OFCI, 120, 264N, 572W, 95, 0, HU, 34, NEQ, 0, 0, 0, 0,
Member Since: September 2, 2009 Posts: 130 Comments: 21193
Quoting Tazmanian:
UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 8.1.1
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 22 AUG 2010 Time : 234500 UTC
Lat : 13:34:52 N Lon : 35:32:27 W


CI# /Pressure/ Vmax
3.3 / 996.4mb/ 51.0kt


Final T# Adj T# Raw T#
3.3 3.4 3.4




note 3.0 is 50kt so this is now a 60 mph storm


That's just one satellite estimation. But if that one satellite estimation is correct, then yes it is a 60 mph storm. But I think it's too aggressive.
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1515. Patrap
00z Early Cycle NHC model tracks
Statistical/Simple Models (CLIPER,BAMs,LBAR,other Statistical Models)




Dynamic Models (More sophisticated models)


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Hurricaneer: What unusual items for a hurricane? I posed that question a few days back but here you go:
An elevated fortress for a home. UHT Shelf-Stable Milk, french press for coffee, canned french butter, shelf-stable cheese, valium, cigarettes, top shelf liquor, disposable plates & utensils, gatorade, powdered hummus & falafel, jars of pesto, 2 gallons of trail mix, extra ammunition, huge ziplock bags, dried meats like salami, camp stove, lots of tarps, rope, ax, gas powered chainsaw, dry ice, tabletop ice maker (only need to crank up the ginny for about an hour to get enough ice for the day), frozen two-liters, DEET, hand sanitizer, cucumber green tea baby wipes (hurricane bath), leave-in hair conditioner, disposable gloves, extra antibiotics (buy fish antibiotics if you don't have any prescribed ones kicking around - skip the tricyclics though), good water filter & water purification tablets, and a BOAT.

There's much, much more, but I'll spare you. Suffice to say that we went for a very long time without power or clean tap water following Katrina, and I'm still a little PTSD'd out about the experience.
I love NOLA. I ain't budging. And dang it, I like to survive in style.
Patrap, dawlin, you're welcome here next time something hits. You know we'll be grilling.
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Quoting MiamiHurricanes09:
So SAB says 50mph TS, let's see what the more aggressive TAFB says.


That would be something if its at 3.5.
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Quoting Stormchaser2007:

There are a couple of near PR hurricanes, and that is spine-chilling :{
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Quoting P451:


True movement or a center fix/relocation?

Meanwhile, you nailed it this morning when you said the exposed center moving north was temporary and would get pulled back west into the convection.

Good job with that!
That's the center fix from SAB...a satellite agency.
Member Since: September 2, 2009 Posts: 130 Comments: 21193
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UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 8.1.1
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 22 AUG 2010 Time : 234500 UTC
Lat : 13:34:52 N Lon : 35:32:27 W


CI# /Pressure/ Vmax
3.3 / 996.4mb/ 51.0kt


Final T# Adj T# Raw T#
3.3 3.4 3.4




note 3.0 is 50kt so this is now a 60 mph storm
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So SAB says 50mph TS, let's see what the more aggressive TAFB says.
Member Since: September 2, 2009 Posts: 130 Comments: 21193
glad to see Danielle is not gonna pay anyone a visit. i see people are talking about ri with this storm. wouldn't it be good for Danielle to blow up as big as she wants way out there rather than closer to land? i mean if it blows up now then it will lose most its power before it even gets close to anything if it did decide to make land fall somewhere, right?
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Quoting Grothar:



All you have to do is ask me about it!! Don't forget, I was born on Long Island. Just won't tell you the year.


Wasn't it called Long Peninsula then? ;)
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Quoting MiamiHurricanes09:
Bingo!

22/2345 UTC 13.7N 35.6W T3.0/3.0 DANIELLE

Let's blame this unpredictable path of Danielle on the "Age of Aquarius" and "let the sunshine, let the sunshine in"!!
Link
Member Since: August 25, 2009 Posts: 20 Comments: 6785
Quoting Hurricanes101:


I know I corrected it lol

was thinking 13.7 was the 5pm coordinate
Lol, no problem.
Member Since: September 2, 2009 Posts: 130 Comments: 21193
Quoting Stormchaser2007:

70mph in 3 hours?

This isnt going through any type of RI. Its just blown up some cold convection near the center. IF RI was going to occur, the center would have to be in the middle of the convection which it clearly isnt.

Not sure why a lot of people are getting so excited.



I'd like to argue that train of thought, the last few frames of visible sat imagery shows it fired right on top of the circulation...
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Quoting Stormchaser2007:

70mph in 3 hours?

This isnt going through any type of RI. Its just blown up some cold convection near the center. IF RI was going to occur, the center would have to be in the middle of the convection which it clearly isnt.

Not sure why a lot of people are getting so excited.





Not sure why you seem to assume that I am getting excited. I'm saying IT CAN happen didn't say it WILL happen.
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Quoting MiamiHurricanes09:
Between the advisory and the center fix from SAB, it moved WNW.


I know I corrected it lol

was thinking 13.7 was the 5pm coordinate
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Quoting MiamiHurricanes09:
Bingo!

22/2345 UTC 13.7N 35.6W T3.0/3.0 DANIELLE

Definitely stronger!
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1493. Dakster
Quoting Huracaneer:


Good idea, yeah that would be much easier to deploy without messing my windows. By the way Patrap's 2010 preparedness page is pretty good if you haven't seen it.


Yeah, I have and Patrap does have an excellant page. You asked for the "not normal" stuff...

BTW, forgot to mention: Since you will be running a generator make sure you get carbon monoxide (CO)/fire detectors. You will be amazed at how the generator CO gets into the house. I had one go off in a room that was on the other side of the house from the generator. Every power outage someone dies and/or gets really sick from CO from a generator. Avoid using "fire" for light at bedtime if you can. (candles,oil lamps, mosquito candles, etc..)
Member Since: March 10, 2006 Posts: 0 Comments: 10317
1491. hydrus
Quoting pottery:
Heh!!
Daniele is looking good this evening.
Building convection through the end of DMin too.
Good thing I did not say it was gonna struggle because of Dry Air!
LOL.
Good evening Pott. Danielle is forecast to be a large and intense storm..Your thoughts?
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Quoting MiamiHurricanes09:
Bingo!

22/2345 UTC 13.7N 35.6W T3.0/3.0 DANIELLE


Nice.
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Quoting Hurricanes101:


due west?
Between the advisory and the center fix from SAB, it moved WNW.
Member Since: September 2, 2009 Posts: 130 Comments: 21193
1488. xcool
Hurricanes101 .yea
Member Since: September 26, 2009 Posts: 2 Comments: 15675
1487. Asta
Quoting Grothar:



All you have to do is ask me about it!! Don't forget, I was born on Long Island. Just won't tell you the year.

AHa- so I could ask you what people asked me after Katrina-- Why do you people live there?
But I won't.. I'll just ask- Well what do you want to share about it- if anything?
Member Since: July 4, 2008 Posts: 30 Comments: 1024
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Quoting MiamiHurricanes09:
Bingo!

22/2345 UTC 13.7N 35.6W T3.0/3.0 DANIELLE


interesting
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Quoting extreme236:
Danielle likely a 45-50MPH TS as SC2007 said.

Yup!
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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.