CFHC Talkback For News Story #47:
Newest Talkback: 11:42 PM 08-11 EDT

TD#4 Drops Out
06:55 AM EDT - 11 August 2000

At 11PM last night Tropical Depression 4 dissipated. That small storm could not hold up any longer to outside influences. From the west and east. To the east is the wave area which still hasn't held together well, but still has a chance to form. Aircraft will be checking it out again today. (They did yesterday as well and didn't find anything then).

The area near the Yucatan looks to be close to a repeat of the last Yucatan storm area a few days ago. Therefore, I don't expect much if anything from it, but it'll still require watching.

Alberto is still there, and the Cape Verde wave remains my favored choice for "next development" after it moves west a little.

Comments or Questions? Use the comment button by the story Headline.

Nice Satellite Image of Atlantic (IR Colorized)

Satellite images at: [N.A. visible] (visible -- Daytime Only) [N.A. infrared] (infrared), and [N.A. water vapor] (water vapor)--Nasa source.

Some Forecast models: (NGM, AVN, MRF, ECMWF, ETA)
DoD weather models (NOGAPS, AVN, MRF)
AVN, ECMWF, GFDL, NOGAPS, UKMET

- [mac]

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Displaying Talkbacks #1 - #14 (of 14 total)
TD4 gone.. but TD5 soon! (#1)
Posted by: Richard B (http://www.atlantic-technologies.co.uk) Location: Gloucester, England, UK
Posted On 10:21AM 11-Aug-2000 with id (RQRNQSYNSTNUT*)

Well TD 4 has indeed dissipated, and now looks like the remnants are getting absorbed into the system to the east of it. That system, the one located southeast of Hatteras, once again looks impressive. Visible imagery would indicate a definite circulation but recon flights have so far found nothing! I still hold out that this system will develop into a TD but i dont want to make a suggestion as to where it could go as yet because i have not had chance to study the models. However it will be interesting to see if the remnant circulation from TD4 will be enough to kick start this system..... we will have to wait and see.
And i would also like to discuss the activity currently over Yucatan. It is forecast to enter the steamy waters of the Gulf of Mexico shortly. And looking at it now i would not be surprised to see this system organise and develop quickly once there. The latest visible, and IR, satellite imagery indicates some sort of circulation, and there is already a hint of banding features on the northern half of this system. It too will need to be watched closely over the next day or two.
Alberto looks impressive but is thankfully missing the islands of Bermuda by a comfortable 300-400 miles. It seems that he may become a potent extratropical storm by 72 hours with winds of 70mph! That will be an area i will be watching especially if he takes a northeast turn towards us (us being the UK).
And as for the wave located southwest of the Cape Verde islands, it too has some potential. However Alberto has churned those waters, and it will be a couple of days before the wave enters an area with decent SST's. But then it will need watching closely too.
Well we are still being kept busy.
Take care all.

Yucatan Wave (#2)
Posted by: Rick Location: Mobile, Al
Posted On 10:51AM 11-Aug-2000 with id (RPYNQRNQUNXW*)

I concur with Richard from England on the wave over the Yucatan. It looks organized as well. I have no idea about low level circulation, and the upper level conditions..who knows......but when this blob of thunderstorms works out into the lower Gulf...I can see a rapid development...and then a kick north toward Mobile.....not that I'm hoping or anything....does anyone have any long range forecasts on this?
models (#3)
Posted by: alan Location: orlando
Posted On 11:02AM 11-Aug-2000 with id (RPVNRQUNRRQNRUR*)

A look at the latest MRF and AVN models was very interesting. Neither show much, if any development of the system over the Yucatan over the next few days.
Just looking at the placement of the system, doesn't it look like it further south than what was expected, meaning that it would most likely move into Mexico. If I'm not mistaken, most systems that start here and end up on the north Gulf coast just clip the corner of the Yucatan, not cross the entire pennisula?
Getting back to the models, they both show two tropical systems near Africa. The AVN shows in 72 hours a strong system just south of the Cape Verde Islands and a weaker system to the ese of the islands. The 48 hour MRF is the exact opposite with the stronger system leading the way.
One other point, is it just my imagination or does it seem like, more than usual, we are seeing tropical waves that have every reason to develop but don't? And aren't we seeing a lot of strange storms, i.e. the Bermuda Low and the swirl that crossed the Atlantic without ever gaining any convection?
two other oddities (#4)
Posted by: alan Location: orlando
Posted On 11:04AM 11-Aug-2000 with id (RPVNRQUNRRQNRUR*)

After posting, I remembered that there were other oddities. For one, a tropical depression forming near the Cape Verde Islands very early in the season and Alberto maintaining his strength when he was over low SSTs.
Just something to think about while wave mongering.
Which one will become TD5? (#5)
Posted by: Richard Byett (http://www.atlantic-technologies.co.uk) Location: Gloucester, England, UK
Posted On 11:17AM 11-Aug-2000 with id (RQRNQSYNSTNUT*)

Well having looked at the imagery of the wave to the southwest of the cape verde islands, it looks very impressive. The clouds show a definite circulation and convection is beginning to increas around the centre of the system, especially to the south and west. It looks very promisding and i would not be surprised to see it develop. However, as Alan says above, this season has indeed been full of surprises and unusual systems. Will this remain just a swirl of clouds we have to ask ourselves.
And what about the wave over yucatan? Visible imagery continues to show it as a very well defined system. But looking at IR imagery you get the full picture. Despite the system being overland at the moment there are definite signs of cyclonic structure. For example there are banding features on the northern and western sides of the system. Convection is also strongest around the centre of the system, especially to the west and south. If this system was over water i would say it was most definitely a tropical depression. But as it is over land, this is not likely, but also not impossible! I agree that we may see some rapid development though when the system moves into the Gulf, and those along the western and northern Gulf Coast might want to keep a close eye on this system. I think it may follow the pattern of the season and surprise us all.
And i am still watching the Haterras system. It continues to look impressive, and is now absorbong the remnants of TD 4. I understand an Airforce Recon Flight is going into this sytem later today, so it will be interesting to see if they find anything.
As for the models, they have not really performed well this year so far, so i do not hold much faith in their forecasts. I think it is probably best to watch each system that shows signs of organisation, even if the models do not indicate
anything! Remember this has been a season of odities, and i expect this will continue.
And as for which system will become our 5th Tropical system, who knows, but there are 3 good candidates!

Anyway that is it from me for now. Take care all.
Points of Interest (#6)
Posted by: Ed Dunham Location: Melbourne, FL
Posted On 12:16PM 11-Aug-2000 with id (VSNQVRNRRVNTX*)

Still some interesting things going on in the Atlantic. A minor correction on some of the dialogue though - TD4 did not die out - it actually has become the predominant feature off our east coast. At 15Z it was located at 28.9N 75.1W and it has been moving briskly due east at 15mph over the past few hours. Its forward speed picked up during the night, and at one point (around 06Z) its convection exceeded that of the system to its east (it still does). The system east of TD4 and the baroclinic low that tried to form north of it have both declined considerably. Would not surprise me at all to see this one reinstated (or ignored). A few other meteorologists have felt that NHC was a bit premature in dropping this system. Anyway, for those that are tracking, here are the satellite derived overnight positions: 00Z 28.8 78.0; 03Z 28.8 77.7; 06Z 28.8 77.2; 09Z 28.9 76.6; 12Z 28.9 75.9.

The system to the east had been drifting north during the night and had been centered at 12Z at 30.6N 72.9W, but I can't locate a center at 15Z.

The Yucatan system is still over land and its movement and strength are being inhibited by an upper level low to its west northwest. Development would be marginal at best.

A small tropical wave is showing some signs of vigor to our south at 24N 80.5W - too early to tell on this one.

Finally, the system southwest of the Cape Verde Islands is starting to get its act together near 13.5N 21W at 15Z. Structure looks good on this one and I'd suspect a TD within 24 hours.

Alan makes a good point about the oddities of this season so far. A La Nina based early season which did not really materialize (TDs notwithstanding). An ITCZ which was more south than normal (until recently). Its as though some critical factor was missing, however the real core of the season for named storms usually starts around August 12th or 13th and runs for two months so the season is probably still on schedule, and at least nine more named storms seem realistic from this weatherman's point of view. Anybody else have thoughts to share on this season and/or its oddities?
Cheers,
ED
Correction (#7)
Posted by: Ed Dunham Location: Melbourne, FL
Posted On 12:32PM 11-Aug-2000 with id (VSNQVRNRRVNTX*)

Make that 13.5N 31W on the potential system in the far eastern Atlantic (thats what usually happens when I let my fingers do the talking!).
ED
Great discussion Ed! (#8)
Posted by: Bill Location: Tallahassee
Posted On 01:05PM 11-Aug-2000 with id (RPTNQQPNRQTNYT*)

Thanks for sharing your time and expertise with us!

I agree re: TD #4 , being dropped too early. It seems NHC just got tired of it for various reasons. I am always amazed, on the other hand,how they will follow a 'swirl' in the Pacific that has no chance of regenerating, and keep at at TD long after they would have dropped an ATL system (such as 4). I think they are more inclined to ignore 4 rather than reinstate it. Time will tell.

I also noticed the TW firing up to our south. Maybe It's energy will combine with the incipient TD over the Yucatan?

Again, many thanks for sharing your insights and experience with us. Your coments on the progress of the season so far are well thought out and well put.

Overall, I have to say that the level of the forum is much higher than in the past year, kudos to all!
TD#4 and more (#9)
Posted by: Mike C. (http://flhurricane.com) Location: Orlando, FL (Currently)
Posted On 01:06PM 11-Aug-2000 with id (RPWNSPNWTNRPW*)

I wrote the update fairly quickly this morning. I've been busy today so I haven't had the chance to really get a good look at the sitation. But it seems TD#4 may redevelop. Ed's made some really good points (and thanks for the coordinates), and the systems in the east Atlantic are looking better too.


When I get back at the end of the day I'll make a new update with everything new.


Thanks again.

Further comment (#10)
Posted by: Bill
Posted On 01:09PM 11-Aug-2000 with id (RPTNQQPNRQTNYT*)

Agree that next TD will come out of Cape verde system, unless disturbance off NC or 'the depression formerly known as 4" fire right back up.

IHS,

Bill
Flow reversal over Gulf and straits (#11)
Posted by: Bill
Posted On 01:12PM 11-Aug-2000 with id (RPTNQQPNRQTNYT*)

Hmmm, interesting, took a look at the radar for S Fl and couldn't help but note the flow pattern has switched entirely to a west to east path as far as the precip is concerned.



IHS,

Bill
Ecoast Tropical Cyclone activity (#12)
Posted by: Bill Location: Tallahassee
Posted On 05:51PM 11-Aug-2000 with id (RPTNQQPNRQTNYT*)

Looks like the E coast is going to be a hotspot for TC formation this weekend.

First, the low off NC has come to the surface and is developing rapidly.

Second, the former TD4 area has been flaring all day and now for the first time I see a circulation forming on the north end of the cloud area.

I wonder how td 4 and (probable 5/6)) will interact? Could be interesting!


Meanwhile, off the African coast...almost a td there, probably will be soon, so it may be #5 or #6. Looks like it is moving wnw already, so may be another fish storm. Waters are warming up pretty well out there, so that isn't an immediate problem.

Finally, the system in the Campeche is moving just N of west and is off the Yucatan now; looks like it is beginning to organize and spin up to...but it has to get down to the surface first, and overcome some shear. Where wil it go, hmmm, hard to say.


The weekend line-up..I think..:

td forms off East Coast and moves NNE to NE, could be an eastern N England threat as a tropical storm or hurricane.

td forms off Africa and moves w or wnw, will become a storm, and possibly later a hurricane.

TD 4 regenerates, uncertain as to more than that.

Campeche system struggles, may become td over weekend , or not.

See you all Saturday. Don't forget to look at the Perseids before dawn saturday!

IHS,

Bill

PS looks like Richard mifght eventually be dealing with Alberto in England!(as an extra-tropical storm...barely ex-t.
Alberto (#13)
Posted by: Richard Byett (http://www.atlantic-technologies.co.uk) Location: Gloucester, England, UK
Posted On 06:13PM 11-Aug-2000 with id (RQRNQSYNSSNQPY*)

It does indeed look like i may have Alberto on my doorstep next week! Not as a hurricane but as an extra-tropical storm! This aint that unusual. Back in 1996 we had the remnants of Hurricane Lili. The centre passed to the north of where i live but gave winds in excess of 100mph! Alberto could be very potent if it gets here too!

But what about the Hatteras Low, and the remnants oof TD 4? I agree that NHC was too early in dropping TD4... it now looks like it is really beginning to flare up. We will need to watch it over the next couple of days!
And the Hatteras Low looks like it is now organising much better, with storms flaring up nearer the centre. I understand NHC may be looking to declare it TD5 later this evening. It will be interesting to see what happens with both these systems as they are in close proximity to each other.

And the Yucatan system. It does not look quite as impressive as it did earlier, but now it is over the warm Gulf waters it may be reorganising. It too looks promising, and as it heads in a general northerly direction the Gulf Coast should monitor it closely. Wind shear may be inhibiting any significant development initially but we must watch this area over the next day or two.

The wave to the west of the Cape Verde islands continues to organise and now looks impressive on imagery. I would not be surprised to see a tropical storm from this sytem within the next couple of days.

And finally a bit on the oddities of the season so far... many mentioned above but here is the latest.... NHC predicted little change in intensity with Alberto, yet sustained winds increased from 85-90 mph..... to over 105 mph in 6 hours! Now i think this season is just weird! Watch carefully because we dont know what might, or might not, happen!

Take care all.
Alberto Looks Stronger (#14)
Posted by: clyde w. Location: orlando
Posted On 07:42PM 11-Aug-2000 with id (VSNWSNRQSNU*)

Alberto looks stronger in the last few satellite loops. Possibly a cat 3 before weakening?

As for the other systems, here's my best guess. Cape Verde becomes Beryl, and of the NC system and Yucatan system, one of them becomes Chris. I'm leaning toward the Yucatan system, there was some circulation earlier. As for NC, that system has been out there looking impressive for days and hasn't got its act together yet. Of course, odds are as soon as I post, NHC will make it a depression, but I did get TD #4 right last night. Love to hear your thoughts on what might be in the next 2-3 days.
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