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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I'd lay good money this will get some interest tomorrow...

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Member Since: Posts: Comments:
Quoting DestinJeff:
Are there any other horrific storms of the past that we can compare Danielle to?
Too many.
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Quoting DestinJeff:
Are there any other horrific storms of the past that we can compare Danielle to?

Will this one do? Link (Wiki page for Super Typhoon Tip)
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Quoting RitaEvac:
FEMA will stagger to knock on the door, as they will be literally bankrupt
Yeah...The last thing this country needs right now is another natural disaster.
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Quoting DestinJeff:
Are there any other horrific storms of the past that we can compare Danielle to?
Charley, Ivan, Georges...

Ok, I'm out. Lurk mode.
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824. xcool


18z nam 500mb
Member Since: September 26, 2009 Posts: 2 Comments: 15624
Quoting wunderkidcayman:
TS Danielle is now moving W-WNW dispite what the NHC is saying and also if you look in this Grapic you can see the track



look at the last few miles of movement you will see it
StormW said earlier the major reason for the northward jog was that td6 now
Dannygirl was feeling a weakness in the ridge to its north, and that when it built back in it would resume a more westward track for 1-3 days. So, that change is not shocking.


edit: he said more westward than current tracks indicated in the morning, as in wnw, not saying he said it would move west, nor am i atm
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FEMA will stagger to knock on the door, as they will be literally bankrupt
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Quoting RitaEvac:
Expect major shift west in coming days as ridge will be building in down the road. Remember Andrew track, and remember Ike track. Major implication changes are underway my friends. This marks the beginning of the wild ride to the heart of season of chaos and destruction

wow Rita what makes you feel this way... I don't want FEMA knocking at my door.
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Quoting catastropheadjuster:
I just got a text and we have Danielle
Yes we do and there are only a few left on here to even chat about it.... LOL
Quoting CosmicEvents:
Seems like 1/2 the people in here have been reported, and the other 1/2 deported. We have at least 100 posts saying "I'm reporting you". Why take up space saying it...just go ahead and do it.

I agree :o)

Taco :o)
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Quoting IKE:
WITH THE EXCEPTION OF THE GFDL...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. FOR NOW...THE OFFICIAL INTENSITY
FORECAST IS LEFT UNCHANGED OUT OF RESPECT FOR CONTINUITY.


Interesting.
Not good.So it seems my Ike or Andrew track isn't for off.And sorry about that hydrus.4th storm.
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Expect major shift west in coming days as ridge will be building in down the road. Remember Andrew track, and remember Ike track. Major implication changes are underway my friends. This marks the beginning of the wild ride to the heart of season of chaos and destruction
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TropicalStormDanielle's heading has turned westward from 0.6degrees north of Northwest to 0.2degrees west of WestNorthWest.
- Date - - - Time - - - - - Location - - Windspeed - Pressure
21Aug - 09pmGMT - 11.0n32.1w - - 30mph . . . . . 1008mb - NHC.Adv.1
22Aug - 12amGMT - 11.2n32.3w - - 25knots . . . . 1008mb - NHC-ATCF
22Aug - 03amGMT - 11.3n32.6w - - 35mph . . . . . 1008mb - NHC.Adv.2
22Aug - 06amGMT - 11.7n33.0w - - 30knots . . . . 1007mb - NHC-ATCF *was11.8n*
22Aug - 09amGMT - 12.1n33.4w - - 35mph . . . . . 1007mb - NHC.Adv.3
22Aug - 12pmGMT - 12.2n33.9w - - 30knots . . . . 1007mb - NHC-ATCF
22Aug - 03pmGMT - 12.7n34.1w - - 35mph . . . . . 1007mb - NHC.Adv.4
22Aug - 06pmGMT - 13.2n34.6w - - 30knots . . . . 1007mb - NHC-ATCF
*before NHC reevaluated&altered TD6's path*
22Aug - 09pmGMT - 13.4n35.1w - - 40mph . . . . . 1005mb - NHC.Adv.5

Copy&paste 12.1n33.4w-12.2n33.9w, 12.2n33.9w-12.7n34.1w, 12.7n34.1w-13.2n34.6w, 13.2n34.6w-13.4n35.1w, hex, bda, sid into the GreatCircleMapper for a look at the last 12hours.
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Statement as of 5:00 PM AST on August 22, 2010

strong showers and thunderstorms...with very cold cloud tops to near
-85c...have recently formed in association with the cyclone...and
the low-level center is now embedded beneath the convective canopy.
Dvorak final T-numbers from TAFB and SAB are now both 2.5...35
kt...and the most recent 3-hour average ADT from UW-CIMSS is 2.7.
The depression is therefore upgraded to a 35-kt tropical storm.
Given the northward movement of the center of Danielle through much
of the day...the estimated initial motion is 310/10. However...
recent satellite images suggest that the center is turning back
toward the west-northwest...and this motion is expected to continue
for the next 72 hours as the system is steered by the subtropical
ridge to its north. A break in the ridge by day 3 could allow the
cyclone to turn toward the northwest...but Danielle is expected to
slow down as it approaches a new ridge to its north on day 5.
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798. JLPR2
Quoting MiamiHurricanes09:
May I add:

3. Deported
4. Reported


#1 should be poof. -.-

I wonder if we could see a yellow circle with the wave at the coast by tomorrow.
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Quoting markot:
nhc said earlier it will miss trof, and slow down and turn west day 4=5


Yes, but there will be another one
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TS Danielle is now moving W-WNW dispite what the NHC is saying and also if you look in this Grapic you can see the track



look at the last few miles of movement you will see it
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Quoting IKE:


Two words I hate now....

(1)Fish.
(2)West.
What about left and out to sea!
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Quoting thewindman:
Backing off on Strength again in the discussion. My feeling is 60mph tropical strom at best. Shear is abudant in the Atlantic this year and therefore it has been a SLOWER than average hurricane season. Sorry you overpaid experts
this WILL be a hurricane. Just might not be our first major, which is good for everyone involved if the westward trend and stronger ridging continues.
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nhc said earlier it will miss trof, and slow down and turn west day 4=5
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Quoting IKE:


Two words I hate now....

(1)Fish.
(2)West.
I hate the thought of West alot more than fish!
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Quoting DestinJeff:
Don't forget about Frances!
nhc didn't, which is why in their discussion they are not even speculating about longer term track tendencies despite the model guidance, which in of itself is noteworthy. Will be interesting to see where this is moving in two days, that should be the key. nice to see the dry air and shear it will be interacting with over the next two days, that should at least protect wherever this goes from seeing the 4/5 everyone was calling for yesterday.
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I just got a text and we have Danielle
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If it were to be weak and miss the trough....it may become stronger in the long run.
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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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