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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northwest movement now?
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Fish storm? I dunno but, you sure have to wade through a bunch of carp on this blog to find some useful information right now.
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We got Danielle against all odds moving NW.
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Quoting duajones78413:
What are the chances of a solid east coast hit?



its small at this time
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A path out to sea is still the most likely solution at this time, but were talking about something more than a week away from any landmasses.
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723. IKE
At 11am EDST....was at....

12.7N and 34.1W

At 5pm EDST....is at.....

13.4N and 35.1W

Moved .7N and 1.0W.
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What are the chances of a solid east coast hit?
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718. FLHL2
and we have Danielle
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717. xcool
to me move wnw
Member Since: September 26, 2009 Posts: 2 Comments: 15649
000
WTNT41 KNHC 222044
TCDAT1
TROPICAL STORM DANIELLE DISCUSSION NUMBER 5
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL062010
500 PM AST SUN AUG 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. THE
NEW OFFICIAL FORECAST IS A LITTLE NORTH OF THE PREVIOUS FORECAST
DURING THE FIRST 72 HOURS TO ACCOUNT FOR THE INITIAL POSITION...BUT
IT CONVERGES BACK WITH THE PREVIOUS FORECAST ON DAYS 4 AND 5. THERE
HAS BEEN NO SIGNIFICANT SHIFT IN THE MODEL GUIDANCE SINCE THE LAST
ADVISORY...AND THE MULTI-MODEL CONSENSUS TVCN IS EXTREMELY CLOSE TO
OFCI.

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.

FORECAST POSITIONS AND MAX WINDS

INITIAL 22/2100Z 13.4N 35.1W 35 KT
12HR VT 23/0600Z 14.0N 36.6W 35 KT
24HR VT 23/1800Z 14.9N 39.2W 40 KT
36HR VT 24/0600Z 16.0N 42.0W 50 KT
48HR VT 24/1800Z 17.3N 44.9W 60 KT
72HR VT 25/1800Z 20.0N 50.0W 70 KT
96HR VT 26/1800Z 23.0N 54.0W 75 KT
120HR VT 27/1800Z 25.5N 57.0W 85 KT

$$
FORECASTER BERG
Member Since: Posts: Comments:
712. SLU
000
WTNT41 KNHC 222044
TCDAT1
TROPICAL STORM DANIELLE DISCUSSION NUMBER 5
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL062010
500 PM AST SUN AUG 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. THE
NEW OFFICIAL FORECAST IS A LITTLE NORTH OF THE PREVIOUS FORECAST
DURING THE FIRST 72 HOURS TO ACCOUNT FOR THE INITIAL POSITION...BUT
IT CONVERGES BACK WITH THE PREVIOUS FORECAST ON DAYS 4 AND 5. THERE
HAS BEEN NO SIGNIFICANT SHIFT IN THE MODEL GUIDANCE SINCE THE LAST
ADVISORY...AND THE MULTI-MODEL CONSENSUS TVCN IS EXTREMELY CLOSE TO
OFCI.

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.

FORECAST POSITIONS AND MAX WINDS

INITIAL 22/2100Z 13.4N 35.1W 35 KT
12HR VT 23/0600Z 14.0N 36.6W 35 KT
24HR VT 23/1800Z 14.9N 39.2W 40 KT
36HR VT 24/0600Z 16.0N 42.0W 50 KT
48HR VT 24/1800Z 17.3N 44.9W 60 KT
72HR VT 25/1800Z 20.0N 50.0W 70 KT
96HR VT 26/1800Z 23.0N 54.0W 75 KT
120HR VT 27/1800Z 25.5N 57.0W 85 KT

$$
FORECASTER BERG



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Quoting Ameister12:
We got Danielle.



Yep
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We got TS Danielle folks!

5:00 PM AST Sun Aug 22
Location: 13.4°N 35.1°W
Max sustained: 40 mph
Moving: NW at 12 mph
Min pressure: 1005 mb
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000
WTNT31 KNHC 222043
TCPAT1
BULLETIN
TROPICAL STORM DANIELLE ADVISORY NUMBER 5
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL062010
500 PM AST SUN AUG 22 2010

...DEPRESSION BECOMES FOURTH TROPICAL STORM OF THE SEASON...


SUMMARY OF 500 PM AST...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...13.4N 35.1W
ABOUT 725 MI...1165 KM W OF THE SOUTHERNMOST CAPE VERDE ISLANDS
MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/HR
PRESENT MOVEMENT...NW OR 310 DEGREES AT 12 MPH...19 KM/HR
MINIMUM CENTRAL PRESSURE...1005 MB...29.68 INCHES


WATCHES AND WARNINGS
--------------------
THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.


DISCUSSION AND 48-HOUR OUTLOOK
------------------------------
RECENT SATELLITE IMAGES INDICATE THAT THE DEPRESSION OVER THE
EASTERN ATLANTIC HAS STRENGTHENED INTO TROPICAL STORM DANIELLE.

AT 500 PM AST...2100 UTC...THE CENTER OF TROPICAL STORM DANIELLE WAS
LOCATED NEAR LATITUDE 13.4 NORTH...LONGITUDE 35.1 WEST. DANIELLE IS
MOVING TOWARD THE NORTHWEST NEAR 12 MPH...19 KM/HR. A TURN TOWARD
THE WEST-NORTHWEST WITH AN INCREASE IN FORWARD SPEED IS EXPECTED
LATER TONIGHT.

MAXIMUM SUSTAINED WINDS HAVE INCREASED TO NEAR 40 MPH...65
KM/HR...WITH HIGHER GUSTS. ADDITIONAL STRENGTHENING IS FORECAST
DURING THE NEXT 48 HOURS...AND DANIELLE COULD BE NEAR HURRICANE
INTENSITY BY LATE TUESDAY.

TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 50 MILES...85 KM
FROM THE CENTER.

ESTIMATED MINIMUM CENTRAL PRESSURE IS 1005 MB...29.68 INCHES.


HAZARDS AFFECTING LAND
----------------------
NONE.


NEXT ADVISORY
-------------
NEXT COMPLETE ADVISORY...1100 PM AST.

$$
FORECASTER BERG
Member Since: Posts: Comments:
000
WTNT31 KNHC 222043
TCPAT1
BULLETIN
TROPICAL STORM DANIELLE ADVISORY NUMBER 5
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL062010
500 PM AST SUN AUG 22 2010

...DEPRESSION BECOMES FOURTH TROPICAL STORM OF THE SEASON...


SUMMARY OF 500 PM AST...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...13.4N 35.1W
ABOUT 725 MI...1165 KM W OF THE SOUTHERNMOST CAPE VERDE ISLANDS
MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/HR
PRESENT MOVEMENT...NW OR 310 DEGREES AT 12 MPH...19 KM/HR
MINIMUM CENTRAL PRESSURE...1005 MB...29.68 INCHES


WATCHES AND WARNINGS
--------------------
THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.


DISCUSSION AND 48-HOUR OUTLOOK
------------------------------
RECENT SATELLITE IMAGES INDICATE THAT THE DEPRESSION OVER THE
EASTERN ATLANTIC HAS STRENGTHENED INTO TROPICAL STORM DANIELLE.

AT 500 PM AST...2100 UTC...THE CENTER OF TROPICAL STORM DANIELLE WAS
LOCATED NEAR LATITUDE 13.4 NORTH...LONGITUDE 35.1 WEST. DANIELLE IS
MOVING TOWARD THE NORTHWEST NEAR 12 MPH...19 KM/HR. A TURN TOWARD
THE WEST-NORTHWEST WITH AN INCREASE IN FORWARD SPEED IS EXPECTED
LATER TONIGHT.

MAXIMUM SUSTAINED WINDS HAVE INCREASED TO NEAR 40 MPH...65
KM/HR...WITH HIGHER GUSTS. ADDITIONAL STRENGTHENING IS FORECAST
DURING THE NEXT 48 HOURS...AND DANIELLE COULD BE NEAR HURRICANE
INTENSITY BY LATE TUESDAY.

TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 50 MILES...85 KM
FROM THE CENTER.

ESTIMATED MINIMUM CENTRAL PRESSURE IS 1005 MB...29.68 INCHES.


HAZARDS AFFECTING LAND
----------------------
NONE.


NEXT ADVISORY
-------------
NEXT COMPLETE ADVISORY...1100 PM AST.

$$
FORECASTER BERG
Member Since: Posts: Comments:
Quoting Tazmanian:



looks like you dont look at mode runs i see



mode runs are turning more W


I do look at them. So! Colin's models shifted to the west and where did he end up? Its the same thing with everyone of these storms like this. Most models show it going out to sea, the NHC track shows the same. A couple of models shift left and everyone from NYC to the Keys need to keep an eye on it....Then a few model runs later it shifts back to the right! LOL enough already! Its not downcasting or anything else, just the facts.
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Zegama cerrect.The tropics will be busy these following weeks.
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We got Danielle.
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Quoting philliesrock:
It appears there are 3 camps in today's 12z Euro Ensembles:

1. Harmless recurve out to sea: 20% of members.
2. Bermuda hit/slightly east of Bermuda, then out to sea: 50% of members.
3. Bermuda hit/south of Bermuda, then East Coast brush or hit: 30% of members.

I'm leaning towards #2 at the moment personally.


Option #4, solid East Coast hit.
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697. SLU
...DEPRESSION BECOMES FOURTH TROPICAL STORM OF THE SEASON...


SUMMARY OF 500 PM AST...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...13.4N 35.1W
ABOUT 725 MI...1165 KM W OF THE SOUTHERNMOST CAPE VERDE ISLANDS
MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/HR
PRESENT MOVEMENT...NW OR 310 DEGREES AT 12 MPH...19 KM/HR
MINIMUM CENTRAL PRESSURE...1005 MB...29.68 INCHES

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"This is not a fish"

"This is a fish"


The arguments are stupid right now, fact is we don't know what it is going to do

you think you would ever see the NHC use that kind of language?


Member Since: March 10, 2010 Posts: 1 Comments: 7559
Am I the only one taking the current situation out in the tropics seriously?.C'mon people.
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Anybody had a look at the GOM Lately? Plenty of Divergence, a little convergence, a bit or 850 and 700 vorticity? Could this be a little mischief occuring?
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Quoting washingtonian115:
Yes a ridge is expected to build back in.But I think Danielle will find a weakness in the ridge.However the same cannot be said for the storm that will be followig it.


Perhaps the beginning of a long game of "Red Rover" w/ Africa. Should be interesting.
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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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