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 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.
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281. Vero1
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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
+1!
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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
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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.
You are so correct to check with agent and READ YOUR POLICY. If memoryv serves correct I think the policy I had called for a "named storm of tropical origins" or some thing like that!!!!Read it so you know!!!!
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yea the 12Z ECMWF puts it right over Bermuda

I could care less where it goes from there, that is not good
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274. xcool
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Models are now coming into agreement on a strong ridge building over 06L as it misses the first recurvature. What happens beyond there is uncertain.
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272. IKE
168 hr. 12Z ECMWF...

Member Since: June 9, 2005 Posts: 23 Comments: 37858
Quoting DestinJeff:
ECMWF way east again this 12Z


LOL. Love those 'muddles'....
Member Since: October 24, 2005 Posts: 0 Comments: 23903
As a "westcaster" td6 is organizing once again and has commenced a westward movement once again, it should cross right over the next forecast point, if not a little south of it, it only gave the appearance in had crossed north, look at the visible loop.
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267. xcool
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18Z position forecast verification

From 1st forecast (24 hour)
2010082118 03 OFCL 24 126N 354W 45 0 TS

Actual position
AL 06 2010082218 01 CARQ 0 132N 346W 30 1007 TD

Difference of ~68 miles

From 3rd forecact (12 hour)
2010082206 03 OFCL 12 126N 346W 35 0 TS

Actual position
AL 06 2010082218 01 CARQ 0 132N 346W 30 1007 TD

Difference of ~42 miles
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Wow, the ECMWF destroys Bermuda.
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261. Vero1
Thanks
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yes jurakantaino it did but then turned north then NNW then NW and now WNW I expect it to move even more west soon and also it has slow down when it started to move NNW
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259. xcool
F4PHANTOM .ECMWF LOST RIGTH NOW.
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Quoting F4PHANTOM:
What happened to EARL????


Too busy making a sandwich.

--

T# - technique, i.e. short for Dvorak Technique.

Pertaining to which, appears to sufficiently support an upgrade whilst the visual appearance may be minimal.

However, worse have been upgraded.
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257. 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
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Quoting CosmicEvents:
Enough to make a grown man cry like a baby.


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.
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Quoting Neapolitan:
Several spots with extremely high TCHP numbers. (Click for a larger image):



...and look at the expanding area with 26.C waters down to nearly 600 feet below the surface. You know the comparisons: two football fields...a 60-story building...more than a tenth of a mile. It's gonna take a couple of parked Camille's to drain the Viagra out of that mess (click for larger image):


Based on this information, wha do you think about the stationary circulation at 17.2N 85.0W ?
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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
22Aug - 06pmGMT - 13.2n34.6w - - 30mph . . . . . 1007mb - NHC-ATCF
*before NHC reevaluated&altered TD6's path*
Copy&paste 11.7n33.0w-12.1n33.4w, 12.1n33.4w-12.2n33.9w, 12.2n33.9w-12.7n34.1w, 12.7n34.1w-13.2n34.6w, hex, bda, sid into the GreatCircleMapper for a look at the last 12hours. TD6's heading has turned westward from 1.1degrees north of NorthNorthWest to 0.6degrees north of Northwest.
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251. xcool
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250. Vero1
Quoting Tazmanian:
CI# /Pressure/ Vmax
2.9 /1001.0mb/ 43.0kt


Final T# Adj T# Raw T#
2.4 2.8 2.8



going up


Taz, what is "T#"?
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Becoming windy, here in the Mid-Atlantic, as there is a storm here, on its way.



CMC closes up the weakeness in the ridge, and the storm starts heading towards my area! O.o

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hello all just wondering at what point would it be, a better handle of possible east coast or southern new england strike or not strike . cause i know sitting here in southeastern mass knowing we have been lucky to have fronts come threw intime to kick storms out to sea missing us that one day there with be a storm the doesnt have a frontal system sweeping threw here to kick it out leaving the door open
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247. xcool

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


Final T# Adj T# Raw T#
2.4 2.8 2.8



going up
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Quoting MiamiHurricanes09:
Yes. Anywhere from South Carolina northwards should be keeping an eye on this. Something like what the 00z ECMWF shows could be very bad with the trough lifting out and a strong ridge building in forcing the 'major hurricane' right towards the eastern seaboard. There's a good chance that it'll recurve, but regardless, keep an eye on it.


Thanks! This will be a tricky one to forecast, that's for sure!
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Storm firing right over the center:

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243. IKE
Only 82.1 here in the Florida panhandle this afternoon.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Several spots with extremely high TCHP numbers. (Click for a larger image):



...and look at the expanding area with 26.C waters down to nearly 600 feet below the surface. You know the comparisons: two football fields...a 60-story building...more than a tenth of a mile. It's gonna take a couple of parked Camille's to drain the Viagra out of that mess (click for larger image):
Member Since: November 8, 2009 Posts: 4 Comments: 13442
Quoting KEEPEROFTHEGATE:
06L/XX/XX
MARK
13.37N/34.52W


Thunderstorms are grouping around the center. Stregnthening can now be anticipated.
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Quoting FLdewey:

Yep. 2004 brought me a new understanding of homeowners insurance.


LOL.. Like that 1% hurricane increase every year? I have State Farm and they are always increasing my premiums.
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ECMWF 12z 144 hours:

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237. xcool


OUT SEA
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634

WHXX01 KWBC 221829

CHGHUR

TROPICAL CYCLONE GUIDANCE MESSAGE

NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL

1829 UTC SUN AUG 22 2010



DISCLAIMER...NUMERICAL MODELS ARE SUBJECT TO LARGE ERRORS.

PLEASE REFER TO NHC OFFICIAL FORECASTS FOR TROPICAL CYCLONE

AND SUBTROPICAL CYCLONE INFORMATION.



ATLANTIC OBJECTIVE AIDS FOR



TROPICAL CYCLONE SIX (AL062010) 20100822 1800 UTC



...00 HRS... ...12 HRS... ...24 HRS. .. ...36 HRS...

100822 1800 100823 0600 100823 1800 100824 0600



LAT LON LAT LON LAT LON LAT LON

BAMS 13.2N 34.6W 14.2N 36.1W 15.6N 38.6W 17.3N 41.9W

BAMD 13.2N 34.6W 14.0N 36.6W 15.1N 39.0W 16.2N 41.5W

BAMM 13.2N 34.6W 14.2N 36.5W 15.4N 39.2W 16.7N 42.4W

LBAR 13.2N 34.6W 14.0N 36.9W 15.1N 40.1W 15.9N 43.2W

SHIP 30KTS 34KTS 42KTS 51KTS

DSHP 30KTS 34KTS 42KTS 51KTS



...48 HRS... ...72 HRS... ...96 HRS. .. ..120 HRS...

100824 1800 100825 1800 100826 1800 100827 1800



LAT LON LAT LON LAT LON LAT LON

BAMS 19.0N 45.6W 21.3N 52.5W 21.3N 57.1W 22.2N 57.1W

BAMD 17.7N 43.9W 21.3N 48.1W 24.8N 51.9W 28.0N 55.2W

BAMM 18.2N 45.6W 20.5N 50.9W 22.2N 54.4W 24.9N 55.5W

LBAR 17.2N 46.8W 19.6N 52.5W 23.5N 54.7W 26.2N 56.9W

SHIP 59KTS 69KTS 73KTS 73KTS

DSHP 59KTS 69KTS 73KTS 73KTS



...INITIAL CONDITIONS...

LATCUR = 13.2N LONCUR = 34.6W DIRCUR = 315DEG SPDCUR = 11KT

LATM12 = 11.7N LONM12 = 33.0W DIRM12 = 303DEG SPDM12 = 9KT

LATM24 = 10.8N LONM24 = 31.8W

WNDCUR = 30KT RMAXWD = 75NM WNDM12 = 30KT

CENPRS = 1007MB OUTPRS = 1012MB OUTRAD = 250NM SDEPTH = S

RD34NE = 0NM RD34SE = 0NM RD34SW = 0NM RD34NW = 0NM



$$

NNNN
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That jog to the NNE of the LLC was at a pretty good clip, 20mph or more?
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Quoting nrtiwlnvragn:
06L 18Z


...INITIAL CONDITIONS...
LATCUR = 13.2N LONCUR = 34.6W DIRCUR = 315DEG SPDCUR = 11KT
LATM12 = 11.7N LONM12 = 33.0W DIRM12 = 303DEG SPDM12 = 9KT
LATM24 = 10.8N LONM24 = 31.8W
WNDCUR = 30KT RMAXWD = 75NM WNDM12 = 30KT
CENPRS = 1007MB OUTPRS = 1012MB OUTRAD = 250NM SDEPTH = S
RD34NE = 0NM RD34SE = 0NM RD34SW = 0NM RD34NW = 0NM


Looks like we could have Danielle at 5pm.
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233. xcool
TD6 MOVE WNW.
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atcf says this is still a TD at 5
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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.