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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Quoting LongIslandXpress38:
I envision a Cat 4 taking out Fenway Park in 14 days..


you must be a Yankees fan then lol
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Quoting pottery:

I think I will leave that alone....


LOL
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Speaking of upper level winds, as of 16:15 UTC the upper level high to the NE of 06L continues to meander westward.

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Quoting RadarNerd:


Hey Storm.. with the L/L grid up the llc motion looks more NNW. The convection moving faster to west of the llc makes it movment look more easterly.

Optical illusion then. Good point.
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CaneFears, your denial is at best, that you are not JFV, but we know better than that. Can I get all 108 different e-mails you have to make parallel accounts?
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Quoting Hurricanes101:
COC is clearly being sucked back into the convection now, the job away from the convection was just a minor and temporary setback
Indeed. The circulation advecting under the convection is a sign of improving conditions. Goes to show that the disturbance to the NE is dissipating along with more favorable upper level winds and lessening dry air.
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COC is clearly being sucked back into the convection now, the job away from the convection was just a minor and temporary setback
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Spell check was me realizing my own transgressions in post 89....but bravo to the words...
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Quoting MiamiHurricanes09:
I'd like to see a video of Jason pronouncing that word. LMAO!


hahaha, its a great word! :p
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Quoting bdkennedy:
Wow, I was really expecting Danielle this morning when I woke up.

I think I will leave that alone....
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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 : 171500 UTC
Lat : 12:52:40 N Lon : 34:22:44 W


CI# /Pressure/ Vmax
2.9 /1001.0mb/ 43.0kt


Final T# Adj T# Raw T#
2.4 2.5 2.5

Latitude bias adjustment to MSLP : +0.0mb

Center Temp : +18.4C Cloud Region Temp : -6.8C

Scene Type : SHEAR (0.43^ TO DG)

Positioning Method : FORECAST INTERPOLATION

Ocean Basin : ATLANTIC
Dvorak CI > MSLP Conversion Used : ATLANTIC

Tno/CI Rules : Constraint Limits : NO LIMIT
Weakening Flag : ON
Rapid Dissipation Flag : FLAG

****************************************************

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Quoting viman:


Did someone say Cruzan Rum...I got plenty of Coca Cola...yummm


Comes in handy when board content degenerates
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Quoting pottery:

Gee, Thanks Snake.
I was sure we had left my "problem" in the last Blog....
heheheheh


You should see a doctor, they have medicine for that.

So does the temporary NORTH movement make the odds for a Bermuda hit BETTER or WORSE?
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Quoting TerraNova:

Exactly what I was thinking!


figured... lol
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Quoting VAbeachhurricanes:


pneumonoultramicroscopicsilicovolcanoconiosis?
I'd like to see a video of Jason pronouncing that word. LMAO!
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Quoting VAbeachhurricanes:


pneumonoultramicroscopicsilicovolcanoconiosis?

Exactly what I was thinking!
Member Since: July 30, 2007 Posts: 76 Comments: 4062
Quoting TerraNova:

...onomatopoeia? antidisestablishmentarianism?


pneumonoultramicroscopicsilicovolcanoconiosis?
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105. Vero1
TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SUN AUG 22 2010

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...SPECIAL FEATURES...

TROPICAL DEPRESSION SIX IS CENTERED NEAR 12.7N 34.1W AT 22/1500
UTC...OR ABOUT ABOUT 665 MI...1075 KM W OF THE SOUTHERNMOST CAPE
VERDE ISLANDS MOVING NW AT 10 KT. ESTIMATED MINIMUM CENTRAL
PRESSURE IS 1007 MB. MAXIMUM SUSTAINED WIND SPEED IS 30 KT WITH
GUSTS TO 40 KT. STRENGTHENING IS FORECAST OVER THE NEXT FEW DAYS
AS THE CYCLONE REMAINS OVER WARM SEA SURFACE TEMPERATURES AND
WITHIN A RELATIVELY LOW NORTHEASTERLY SHEAR ENVIRONMENT. THIS IS
EXPECTED TO PROVIDE AN OVERALL FAVORABLE UPPER LEVEL DIFFLUENT
ENVIRONMENT FOR THE SYSTEM TO MAINTAIN ORGANIZED CONVECTION AND
PROVIDE FOR MINIMAL WIND SHEAR. SCATTERED MODERATE TO ISOLATED
STRONG CONVECTION IS FROM 10N-14N BETWEEN 34W-39W. SEE LATEST
NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21
KNHC FOR MORE DETAILS.
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104. DVG
Quoting StormW:
Never mind...I think some of that motion was due to a big gulp of dry air.

WV LOOP


Contrasting RGB with shortwave, I didn't even notice the NNE on shortwave. On the RGB the difference is easy to recoqnize.

I know only what I've picked up from yuze guys.
My very uneducated guess is this. Perhaps the disturbance to the NE affected the lower circulation, but not all?
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I don't like to quibble but it's Cape Verde Islands not Cape Verdes Islands.
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000
ABNT20 KNHC 221738
TWOAT
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
200 PM EDT SUN AUG 22 2010

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

THE NATIONAL HURRICANE CENTER IS ISSUING ADVISORIES ON TROPICAL
DEPRESSION SIX...LOCATED ABOUT 665 MILES WEST OF THE SOUTHERNMOST
CAPE VERDE ISLANDS.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.

PUBLIC ADVISORIES ON TROPICAL DEPRESSION SIX ARE ISSUED UNDER WMO
HEADER WTNT31 KNHC AND UNDER AWIPS HEADER MIATCPAT1.
FORECAST/ADVISORIES ON THE DEPRESSION ARE ISSUED UNDER WMO HEADER
WTNT21 KNHC AND UNDER AWIPS HEADER MIATCMAT1.

$$
FORECASTER BERG
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Wow, I was really expecting Danielle this morning when I woke up.
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Quoting sporteguy03:


HWRF at the end brings it back more WNW.


Good Afternoon!

HWRF is potentially hinting at an East Coast Storm. GFS seems to be on the furthest right side of the model package.
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Quoting want2lrn:
Spell check...elaborate, knowledgable

...onomatopoeia? antidisestablishmentarianism?
Member Since: July 30, 2007 Posts: 76 Comments: 4062
Quoting weatherman12345:

thats what i said... and is it possible that this coc dissipates and a new one forms under the deep convection??
I doubt it. The COC looks plenty well-defined and appears to be moving generally westward. Should be under the convection completely by 3:00p.m EDT.
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Quoting scottiesaunt:
Stretched blog is a PAIN!!!

Should be gone if you're using Firefox or Chrome or even the latest build of IE.
Member Since: July 30, 2007 Posts: 76 Comments: 4062
Spell check...elaborate, knowledgable
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06L/XX/XX
MARK
13.07N/34.32W
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Quoting RadarNerd:


BTW.. I have not been around or said hi for awhile. I am one of the was fortunate to sit with you through one of your analysis runs a few years back. Brought you the cruzian rum in gratitude for your time. Hope all is well!


Did someone say Cruzan Rum...I got plenty of Coca Cola...yummm
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Quoting TropicalAnalystwx13:


The area of thunderstorm activity is from the tail-end of a front. Some models were developing it the other day, but not, it looks like it wont be a concern.

The wave west of the Antilles does look impressive, however, it probably wont develop in the short term.


Thank you Tropical...is it the high that is over us right now that will keep the GOM system from developing...or wind shear, TUTTS, ULLS? Keep in mind i have almost no idea what i just said! LOL

I lost my tutor....STORM would you please eloborate (or any other knowleable person)
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Quoting RTLSNK:
Sorry Grothar, missed the hyper-jump to the new blog.

Pottery, sorry to hear about your "problem". :)

Quoting Grothar:


Yo, Snake! Doing a little recon on the blog?


Always here reading and learning, more so in the last week after someone mentioned Georgia as a "possible" cane strike target. :)

Macon is 167 miles NW of Savannah so I don't think storm surge will be a problem.

Gee, Thanks Snake.
I was sure we had left my "problem" in the last Blog....
heheheheh
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Stretched blog is a PAIN!!!
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Quoting ShenValleyFlyFish:
Forgive me for I have sinned.

Quoting MiamiHurricanes09:
No one quote post 46. Report it that way its gone.
Hahahaha.
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21Aug - 12pmGMT - 10.6n31.0w - - 25knots . . . . 1009mb
Invest95L becomes TropicalDepressionSix
- Date - - - Time - - - - - Location - - Windspeed - Pressure
21Aug - 06pmGMT - 10.8n31.8w - - 25knots . . . . 1008mb - NHC-ATCF
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
*before NHC reevaluated&altered TD6's path*
Copy&paste 11.3n32.6w-11.7n33.0w, 11.7n33.0w-12.1n33.4w, 12.1n33.4w-12.2n33.9w, 12.2n33.9w-12.7n34.1w, hex, bda, sid into the GreatCircleMapper for a look at the last 12hours. TD6's heading has turned northward from 11degrees west of WestNorthWest to 1.1degrees north of NorthNorthWest.
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About JeffMasters

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.