Tropical Depression Six reorganizing

By: Dr. Jeff Masters , 12:59 AM GMT on September 05, 2006

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Tropical Depression Six is having trouble making up its mind where its center should be. The center it organized around is getting competition from another center of circulation about 400 miles to the southwest, as seen in the latest QuikSCAT image posted at 8:30pm EDT tonight (Figure 1). The large area of thunderstorms about 400 miles southwest of TD 6, formerly designated "Invest 98L", is still there, and is causing major difficulties for TD 6, which can't make up its mind which center to consolidate around. Until the depression resolves this conflict, you can throw all the model runs out the window--they will not be able to resolve the double circulation centers. TD 6 may well decide to organize around the old Invest 98L center to the southwest, which would pull the forecast tracks further south towards the Lesser Antilles Islands. Another wind card is the presence of the new tropical wave to the east of TD 6, near the Cape Verde Islands. This wave is close enough to TD 6 that it may be stealing some energy from the depression and inhibiting its intensification. Again, the models will not be able to deal with this interaction with another circulation nearby.

Despite this conflict, TD 6 has grown stronger since this morning--there are many more red 40 mph wind vectors visible in the evening QuikSCAT pass (Figure 1) compared to the morning pass (Figure 2). It will be interesting to see if NHC upgrades the system to Tropical Storm Florence at 11pm, or decides to wait to see which center TD 6 forms around.


Figure 1. QuikSCAT satellite winds from 5pm EDT Monday evening, September 4, 2006. Wind speed and direction are coded according to the standard station model, and are color coded (in knots) according to the color scale at the upper right (10 knots = 11.5 mph). Black winds barbs occur where there is rain, and one cannot trust the wind speeds measured in those areas. Tropical storm force winds (35 knots) are colored red, brown, or purple; one can see many red wind barbs in TD 6. Note the increased winds (orange barbs, 25-30 knots) around Invest 98L, compared to the morning QuikSCAT pass (below).


Figure 2. QuikSCAT satellite winds from 5am EDT Monday morning, September 4, 2006. One can see one red wind barb in TD 6.

Cape Verdes Islands tropical wave
The wave just west of the Cape Verdes Islands has a closed circulation, which can be seen on QuikSCAT imagery from this morning and this evening (Figures 1 and 2). The wave's winds have not increased between the two passes by the satellite, and TD 6 may be inhibiting the wave's development. The wave is under a modest 10 knots of wind shear, and has some potential for slow development over the next few days.

Next update
I'll have an update Tuesday morning.

Jeff Masters

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873. stormybil
8:47 AM GMT on September 06, 2006
well no change at 5 am can you believe that they must be sleeping at nhc .
872. stormybil
5:28 PM GMT on September 05, 2006
after reading all the info here all i can see is that we might have cat2 or 3 sitting off the east coast of sf . thats not god and if the high build in flo will go the same as andrew and thats west young man . time will time . but will we have enough time thats the question . dont let your guard down . just yet
871. nebula420
1:54 PM GMT on September 05, 2006
Vortex, take a chill pill. To say the NHC prove they are the best each and every storm is laughable. I'll mention it again for all those authority lovers out there. They engage in SWAG's (scientific wild ass guesses) and are just as wrong as they are right.
870. seminolesfan
1:52 PM GMT on September 05, 2006
new blog up!!!
Member Since: June 14, 2006 Posts: 0 Comments: 2108
869. nash28
1:49 PM GMT on September 05, 2006
LMAO Seminoles!!!!
Member Since: July 11, 2005 Posts: 190 Comments: 16972
868. Tazmanian
1:49 PM GMT on September 05, 2006
oh 91L is a little stonger as well 25kts from 20kt and the mb is 1008mb from 1009mb from be for
Member Since: May 21, 2006 Posts: 5091 Comments: 115453
867. vortextrance
1:48 PM GMT on September 05, 2006
Posted By: nebula420 at 1:43 PM GMT on September 05, 2006.
vortex, take a look at the short wave infrared and tell me there is no center coming together. WHY is NHC the best? PHD: Piled higher and deeper, but you are right about one thing, they don't know what is going on each 6 hours any better than anyone else here.


First of all the NHC is the best and they prove it every single storm. You don't find places like accuweather who ever else tries to contradict them being right.
Second I see the coc being the one the NHC says is the one. I see that center as exposed now. Could more convection fire around it, yes. Could a new center take over, yes. My point is that its a waiting game but maybe I am not as smart as you.
Member Since: October 5, 2005 Posts: 0 Comments: 700
866. nebula420
1:47 PM GMT on September 05, 2006
all of a sudden, a new look screen
865. Cavin Rawlins
1:47 PM GMT on September 05, 2006
Weather456’s Tropical and Subtropical Weather Discussion for The North Atlantic Ocean.............Tropical Depression Six………..
Tuesday, September 5, 2006
9:20 AM AST


Tropical Depression Six is located at 17.7N/45.9W, moving WNW at 13mph in the open central Atlantic. The depression is packing winds of 35mph and a MCP of 1007mbar. The depression a bit disorganized this morning with some SW shear affecting it; but continues to maintain its circulation and may merge with the circulation of former 98L (See below).

Surface Observation/Conditions
The depression is moving over waters near 80-82F degrees and the further north it moves into 80F degrees waters.

Wave heights in the open waters around TD6 will be 10ft above normal.

Another area of low pressure (1008mabr) is located to SW of TD6‘s main center.

Buoys and Ships
A ship directly south of the depression’s center measured a pressure of 1009mbar and an east wind of 20knots.

Forecast
The shear from the trough will relax during the next couple of days, allowing some organization to occur and this could become TS Florence within 48hrs, then when it reaches an Upper Level high, could become a hurricane, in about 96-120hrs.

The depression will continue to move WNW to NW, then move more to the west under the influence of a ridge south of Bermuda. Then comes the tricky part, a trough is now located over the USA. When this troughs moves down, if it is able to catch the system, it will move it more to the north, if it misses it, then the system will continue to move west to west-north-west.

Now, if the trough misses the system, it could still weaken the high, allowing the system to ride up the west side of the ridge and out to sea.

So areas of interest are the Turks and Caicos (5%), the Bahamas (5%), Florida (10%), South/North Carolina (15%), Remainder of the East Coast (20%), Canada (15%) and moving out to sea (20%).

Weather456
Member Since: July 24, 2005 Posts: 407 Comments: 19076
862. Tazmanian
1:43 PM GMT on September 05, 2006
we have a TS the navy site has the winds at 35kts and a 1005mb we have a TS
Member Since: May 21, 2006 Posts: 5091 Comments: 115453
861. ricderr
1:43 PM GMT on September 05, 2006
well boys and girls...meeting time..have fun
Member Since: June 27, 2006 Posts: 676 Comments: 22336
860. nebula420
1:43 PM GMT on September 05, 2006
vortex, take a look at the short wave infrared and tell me there is no center coming together. WHY is NHC the best? PHD: Piled higher and deeper, but you are right about one thing, they don't know what is going on each 6 hours any better than anyone else here.
859. seminolesfan
1:43 PM GMT on September 05, 2006
Posted By: nash28 at 1:38 PM GMT on September 05, 2006.
Assclown count thus far today= 1


Hey nash,
are you gonna count individual assclowns or total assclown comments? If we track both each assclown could get a 'dumbshit index' rating of their own.
Member Since: June 14, 2006 Posts: 0 Comments: 2108
858. seafarer459
1:42 PM GMT on September 05, 2006
Lets see if I get this..

"kiss my grits" was the catch phrase of FLO,from the old tv show Alice...

td06 has the potential to become FLO...hmmm.

Trollaway.. apply directly to the blog.x3

Member Since: July 16, 2006 Posts: 2 Comments: 515
857. vortextrance
1:42 PM GMT on September 05, 2006
I agree Gulf, the exposed coc looks to be going due west, away from the convection.
Member Since: October 5, 2005 Posts: 0 Comments: 700
856. Fl30258713
1:42 PM GMT on September 05, 2006
ricderr, you havin' spam and grits for breakfast, sounds good,lol
Member Since: July 24, 2006 Posts: 1 Comments: 987
851. seminolesfan
1:39 PM GMT on September 05, 2006

gatorx-yeah, i'm sure I'll be circus time when we meet again!!!

Enjoy your Mond, oops, Tuesday!!! LOL
Member Since: June 14, 2006 Posts: 0 Comments: 2108
848. vortextrance
1:37 PM GMT on September 05, 2006
It look to me that the stated center is now totaly exposed. If a new center doesn't form and take over or the current one doesn't fire new convection dissipation is a posiblity. The NHC mentions dissipation as possible in their discussion this morning. From that same discussion I gather the NHC really has no clue right now, and given they are the best, I don't thing anybody else does either. I certainly don't.
Member Since: October 5, 2005 Posts: 0 Comments: 700
847. Gatorx
1:37 PM GMT on September 05, 2006
Thanks Seminolefan....off to work..I'll catch with you all this evening.
846. Bonedog
1:36 PM GMT on September 05, 2006
Posted By: GulfScotsman at 1:34 PM GMT on September 05, 2006.
coc near 17/46 ???


Thats what it lookes like from the quicksat
Member Since: July 14, 2005 Posts: 14 Comments: 7418
845. seminolesfan
1:36 PM GMT on September 05, 2006
Gulf-that's what I see(from quickscat)
Member Since: June 14, 2006 Posts: 0 Comments: 2108
842. Gatorx
1:33 PM GMT on September 05, 2006
thelmores-

That is sort of what happened to Jeanne two years ago...just wandering around the high until it found a path...actually made a loop de loop and hit Fl...this is what makes me nervous about this system out there..it is forecasted to recurve just as Jeanne was.
841. Fl30258713
1:33 PM GMT on September 05, 2006
Looks like TD06 is taking off like a bat out of hell to the west. Don't see a stall for today.
Member Since: July 24, 2006 Posts: 1 Comments: 987
839. StormJunkie
1:32 PM GMT on September 05, 2006
Morning ya'll!

I see TD06 is still hanging around. It will get interesting once it gets away from the shear, as thel stated.

Rick, you can easily find some of the best model pages, as well as imager and a lot more from one page.

See ya'll later
SJ
Member Since: August 17, 2005 Posts: 26 Comments: 16874
838. nebula420
1:31 PM GMT on September 05, 2006
I believe if you look at the short wave you will see that the coc has started to come together between the two former centers and appears to be moving westward.
837. Bonedog
1:31 PM GMT on September 05, 2006
cant wait to see what the good Doc has to say about TD6 this morning. That quicksat pass was very impressive with a single closed cirrculation and 30 and 35knt wind barbs
Member Since: July 14, 2005 Posts: 14 Comments: 7418
836. seminolesfan
1:30 PM GMT on September 05, 2006
rick54-wave that was behind

Gatorx-Still no real center; some winds are still TS strenght; starting to org. right now; still some shear; if center pick S side of storm more chance of landfall, if it picks N side more chance of recurve! Did I miss anything important?
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834. Tazmanian
1:30 PM GMT on September 05, 2006
thats in older runs her are the newer runs

Link
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833. thelmores
1:30 PM GMT on September 05, 2006
"Has a system ever bypassed a weakness in a High and decided to just go further West? Is a system moving into a weakness of a High always a given?"

picture a ball on the goung rolling..... if the surface is flat, i will just roll on the surface..... but if there is a "hole" at the surface big enough for the ball to fall into..... thats like a "hole" in the high pressure, or a weakness.....

sometimes the hols is there, but not big enough to let the ball fall all the way in the hole.... or it gets stuck, or in the case of a storm, can stall... or drift......

hope that helps.... somebody had a similar analagy, SJ i think..... it will ride that "high" pressure ridge till it finds a weakness or goes around it......
Member Since: September 8, 2005 Posts: 0 Comments: 3805
832. Fl30258713
1:30 PM GMT on September 05, 2006
New modle runs,last nights comments from Dr Masters. Look forward to new info from him this morning.
Member Since: July 24, 2006 Posts: 1 Comments: 987
831. ricderr
1:29 PM GMT on September 05, 2006
kiss...come back at 8 tonight..you'll fit in well....
Member Since: June 27, 2006 Posts: 676 Comments: 22336
830. Tazmanian
1:28 PM GMT on September 05, 2006
her what dr M say

you can throw all the model runs out the window


LOL
Member Since: May 21, 2006 Posts: 5091 Comments: 115453
829. JoeyG100
1:27 PM GMT on September 05, 2006
GFDL Link
827. Rick54
1:27 PM GMT on September 05, 2006
How about a link to the latest run of the GFDL?
826. seminolesfan
1:26 PM GMT on September 05, 2006
Posted By: thelmores at 1:19 PM GMT on September 05, 2006.
i had a hunch a couple days ago 98l may become the dominant low.... it was the furthest from all the shear.... but i also thought yesterday that 98l would get absorbed.... apparently that didnt happen! LOL


Would agree on both points(as far as past tense thinking)
Just goes to show how lazy TCs are; always 'finding the path of least resistance'; no memory for what they were just doing; just following the energy!!!
Member Since: June 14, 2006 Posts: 0 Comments: 2108
825. Gatorx
1:26 PM GMT on September 05, 2006
Can someone give me a 15 second update as to what changed during the night..i have to leave for work in a few minutes.. I mean someone who knows what they are talking about
823. thelmores
1:26 PM GMT on September 05, 2006
Taz.... until the center of td6 gets better organized, i would throw out the "track" on the model.... but the gfdl certainly could be on to something as far as intensity.....

shear is forecast to be near zero in a day or two.... thus intensity should increase significantly! gfdl has been spitting out cat3/4 for the last several runs..... and i start paying attention..... it is way too early, but this storm has alot of similarities to floyd.........
Member Since: September 8, 2005 Posts: 0 Comments: 3805

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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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