Tropical Depression Six arrives

By: Dr. Jeff Masters , 5:14 PM GMT on August 22, 2010

Share this Blog
4
+

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

Reader Comments

Comments will take a few seconds to appear.

Post Your Comments

Please sign in to post comments.

or Join

Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 332 - 282

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | 56 | 57 | 58 | 59 | 60 | 61 | 62 | 63 | 64 | 65 | 66Blog Index

Quoting Cotillion:
943mb.. high Cat3/low Cat 4 type area.


932mb on day 10
Member Since: Posts: Comments:
330. DDR
Afternoon...
Pottery i just had a heavy shower,another 2 inches in the bag,over 30 inches now...wow!
Member Since: Posts: Comments:
Quoting philliesrock:
The HWRF insists on making a left turn near the end of its forecast period.
Thats the High building back in and the 2cnd trof moving out.
Member Since: June 13, 2009 Posts: 0 Comments: 6706
Quoting Clearwater1:


That is why it is so important to know whether a storm in a true hurricane or only a tropical storm at landfall and when it hits your home. Hurricane = hurricane deductible. Tropical storm = much lower, wind damage deductible. Check with your agent, but that's the way I understand it.
That's a good point. I recently checked on the exact way this works, in Florida anyway.
.
.
I found that in most(if not all) policies, if ANY part of the state is under a hurricane warning...this automatically kicks in the hurricane deductible clause for EVERYONE in the state. In other words, if KEY WEST is under a hurricane warning, and DESTIN gets hit with a different cyclone that's only a tropical storm, even if no weather occurs in KEY WEST...the hurricane deductible is in effect for DESTIN on account of a hurricane warning being in effect on some part of the state when the damage occurs.
.
.
The bottom line is that once the hurricane warning goes up for any inch of the state, everyone's hurricane deductible kicks in.
Member Since: Posts: Comments:
325. IKE
240 hour ECMWF shows a 932mb cane and nothing else through Sept. 1st....

Member Since: June 9, 2005 Posts: 23 Comments: 37858
324. xcool
all w'e can do is keep watch td6.
Member Since: Posts: Comments:
943mb.. high Cat3/low Cat 4 type area.
Member Since: Posts: Comments:
The HWRF insists on making a left turn near the end of its forecast period.
Member Since: Posts: Comments:
Quoting IKE:
Day 9 ECMWF....



943mb?!?! On a global model that's pretty much a Cat5. If that run were to come true Fabian would pretty much be forgotten.
Member Since: Posts: Comments:
Quoting pottery:

It would be SO MUCH BETTER if you (and others who seem to have the same issues) would Flag and Ignore these posts.
Instead of subjecting the rest of us to endless reposts and comments that have nothing to add to this blog.
Couldn't agree more. What does it say about your mind when you attempt to match wits with the mindless!!!
Member Since: Posts: Comments:
Quoting F4PHANTOM:
Throw all the models out and go back to pencil and paper!!!!


I agree. Models should be used as a tool, nothing more. When conveniences become crutches or worse necessities, then we regress as a species. Can you think of any other technologies that started as nice little toys, yet to which some people are now almost addicted?
Member Since: Posts: Comments:
Quoting IKE:
Day 9 ECMWF....


What would that 943 equal in real life?
Member Since: Posts: Comments:
nhc said it will turn west, day 4 or 5.....
Member Since: Posts: Comments:
313. Vero1
Member Since: Posts: Comments:
Quoting philliesrock:

It looks like it begins to move NE and out to sea between 222-240 on the maps I have.


Yes, but for a 12 hour period, that movement observed is insignificant.
Member Since: Posts: Comments:
311. IKE
Day 9 ECMWF....

Member Since: June 9, 2005 Posts: 23 Comments: 37858
Quoting Snowlover123:


ECMWF stalls it, after taking a strange southwest turn. :/

It looks like it begins to move NE and out to sea between 222-240 on the maps I have.
Member Since: Posts: Comments:
309. IKE
I don't see much else through day 8.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Convection blowing up over the center:

Member Since: Posts: Comments:
Quoting IKE:


Agree...on that track and intensity, Bermuda would get rocked.

I think the SE USA is spared from TD6. The NE USA has a chance of feeling something from it. Points north and east from there is a greater chance.


Like to see the HWRF show a more Northern turn surprised it is as far South as it is always seems to the furtherest North.
Member Since: Posts: Comments:
Quoting pottery:

It would be SO MUCH BETTER if you (and others who seem to have the same issues) would Flag and Ignore these posts.
Instead of subjecting the rest of us to endless reposts and comments that have nothing to add to this blog.


I didnt mean to quote him, meant to just put the comment number up and respond

either way I put him on ignore now
Member Since: Posts: Comments:
Quoting IKE:
12Z ECMWF through 240 hours.


ECMWF stalls it, after taking a strange southwest turn. :/
Member Since: Posts: Comments:
296. CaneFears 7:05 PM GMT on August 22, 2010

and you know this how?

seriously get over yourself
Member Since: Posts: Comments:
300. IKE
Quoting philliesrock:
Wow, the ECMWF destroys Bermuda.


Agree...on that track and intensity, Bermuda would get rocked.

I think the SE USA is spared from TD6. The NE USA has a chance of feeling something from it. Points north and east from there is a greater chance.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
299. xcool
taco2me61 hey :)!!
Member Since: Posts: Comments:
Quoting Hurricanes101:
277. CaneFears 6:57 PM GMT on August 22, 2010

JFV if it hits Bermuda at that intensity it could rival what Fabian did to the island in 2003, maybe even worse

show some heart for once

It would be SO MUCH BETTER if you (and others who seem to have the same issues) would Flag and Ignore these posts.
Instead of subjecting the rest of us to endless reposts and comments that have nothing to add to this blog.
Member Since: October 24, 2005 Posts: 0 Comments: 23080
Quoting xcool:
NOT SO FAST MY FRIEND ( WITH THE RECURVE)

One of the "dangers" in this years hurricane forecast was the idea that a storm could hit the coast moving west of north further north than normal. By that I mean storms of the genre if Isabel, and Fran, or the 1933 hurricane or the brave attempt by Felix in 1995. This occurs in years when ridges are prone to build further north than normal during the meat of the hurricane season.


I have been hemming and hawing about what is now td 6 for a while and how in spite of the models turning out, we should not write it off. Truth is, the pattern forecasted day 8-12 is ripe for the US coast to get hit.. I say US coast because one has to watch for activity popping up in the gulf out of this.

But the models have been trending west, most disturbingly the Euro which has major hurricane on day 10 moving west northwest near 30 north and 65 west.

Lets keep in mind that years coming off El Ninos, things like this happen The only year in history a major hurricane struck the Old Coast of Florida from the east.. 1964, ( that was Dora) came off the Nino. Isabel came off the Nino.. Felix came off the nino. And it has to do with the same overall climate response that we caught for the hot summer this year.. post nino years are almost always hot in much of the nation.

Now the flip side of this.. is alot of storms like to turn out quickly. Felix in 1995.. Bonnie, which hit the NC coast in 1998 turned out quickly.

I will be in later today to do the videos. A look at the euro ensembles

http://www.ecmwf.int/products/forecasts/d/charts/medium/eps/ensm/essential!MSLP !North%20America!240!pop!od!enfo!plot_ensm_essential!2010082200!!/


show how far west the variance is by the color spread, as several runs have the storm approaching the NC coast day 10...

The 500 mb shows this too

http://www.ecmwf.int/products/forecasts/d/charts/medium/eps/ensm/essential!Geop otential%20at%20500hPa!North%20America!240!pop!od!enfo!plot_ensm_essential!2010 082200!!/



I apologize for not yet having the moveable type so you dont have to copy and paste the links.


This is an intereting test in that my theory that the ky to getting the season to start was to raise pressures in N America is something that is causing people some degree of consternation ( they disagree). Thats fine, but we will see. There is one heck of a cool shot coming into the nation this week before the summer ends boiling for much of the nation and its interesting to note that in previous years that the change in the weather pattern, or greater variances, suddenly would invite storm development. Which makes sense, because give a set of parameters that WERENT PRODUCING STORMS if you change that, it would make sense to go the other way.


One of the "problems" with TD 6 and perhaps the models is there are two systems.. one off to the northeast, and the modeling may be trying to pick out a mid point between the two. In addition , the cloud shot shows a big system coming off Africa this morning behind this:

http://www.nhc.noaa.gov/satellite.shtml


In any case, this is "tugging" at td 6, retarding quicker westward movement so its now on the east side of its thunderstorms, with a look of the opposite kind of shear that we normally look to inhibit storms. However once the energy is bundled, and this is what the euro is seeing and why it develops this into a major hurricane on the 00z run, it will be free to deepen. This usually takes a few days ( again a look in the Pacific at typhoon evolution is what one needs to do. Many systems out there are double and even triple areas of low pressure within a large "envelope" Interestingly enough, Dora, the 64 storm I referenced, started in much the same manner

A look at the wide cloud shot of the atlantic examplifies my comment a few days ago that before a parade, one can "hear" the band coming before you see it. Like magic, 4 systems show up from the southeast Pacific to Africa

http://www.ssd.noaa.gov/goes/east/tatl/avn-l.jpg

The one on the Pacific side of Mexico is not a US concern but is a case of in close development for Mexico and a problem there.

One sees the depression and what may be two systems, and of course the bomb coming off Africa. Also thunderstorms lurk in the northeast gulf. Notice also if you will how waves with virtually no cloudiness before now have some thunderstorms with them, once they approach and then get by 60 west.

For the gulf.. while there is modeling showing development in the northeast gulf, this trough leaving on the east coast ( and with it a first class summer noreaster for New England) is leaving a piece behind and that is something to watch.



BY JOE B

+ 1

Nice Read There....

Taco :o)
Member Since: Posts: Comments:
Good afternoon, Ive been reading and watching the progress of TD6 over the last couple of days. It seemes like the track of TD6 (according to the experts) keeps getting closer to the United States. At this rate I would expect a landfalling hurricane somewhere on the E coast more than not. The reason I say this is that the language is strong not to let your guard down. Time will tell.
Member Since: June 13, 2009 Posts: 0 Comments: 6706
UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 8.1.1
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 22 AUG 2010 Time : 181500 UTC
Lat : 12:55:17 N Lon : 34:31:47 W


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


Final T# Adj T# Raw T#
2.5 2.9 2.9

Latitude bias adjustment to MSLP : +0.0mb

Center Temp : +14.5C Cloud Region Temp : -4.8C

Scene Type : SHEAR (0.35^ 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 : OFF

Yay lol. Weakening flag still on :/
Member Since: Posts: Comments:
Live tropics talk at www.cyclonezonecz.blogspot.com

its on bottom of page

starting in just a few mins
Member Since: Posts: Comments:
18Z model runs from the NHC


Member Since: Posts: Comments:
It looks like TD6 will eventually slip northward as it passes not far from Bermuda through a weakness between two highs. It looks like a classic fish storm in the making to me.
Member Since: Posts: Comments:
How often do models get intensity correct?

From what I've seen not too often.
Member Since: Posts: Comments:
Quoting Snowlover123:


It's sad how you need to create multiple usernames to just insult people on this blog. Ravage another forum for goodness sake.

please dont quote the iddit
Member Since: Posts: Comments:
287. IKE
12Z ECMWF through 240 hours.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
284. CaneFears 7:01 PM GMT on August 22, 2010

you are kidding right? lol
Member Since: Posts: Comments:
Quoting JFV:


I do. NEXT.


It's sad how you need to create multiple usernames to just insult people on this blog. Ravage another forum for goodness sake.
Member Since: Posts: Comments:

Viewing: 332 - 282

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | 56 | 57 | 58 | 59 | 60 | 61 | 62 | 63 | 64 | 65 | 66Blog Index

Top of Page

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.