Depression developing ESE of Windward Islands

[Jim Leonard]

There is a pretty good looking tropical disturbance developing around 9N and 46W this morning. There is definite rotation in the cloud mass. The enviroment ahead of this system looks favorable for continued development for the next couple of days.

 

[Blake Michaleski]

Jim, That wave is looking quite impressive. It looks to be developing some good upper level outflow in the northern semicircle.

This thing is far enough south that if it were to develop, it would definitely warrant watching.

 

[Jim Leonard]

Looking at the satellite animation this afternoon shows a good circulation but the convection needs to get going a bit more. The diurnal up swing this evening will be interesting to watch.
The models won't be much help with these small systems. I notice the gfs is ignoring it at the moment, the CMC has it going all the way to Honduras. The ecmwf looses in the central Caribbean.
There is another prospect back just SW of the Cape Verde Islands.

 

[Blake Michaleski]

Overall, the deep convection has lessened in the last few hours. That which still remains is near or at the apparent center of circulation. Further latent heat release by this deep convection could lead to deepening of a surface cyclone in the near term.

You're definitely right that tonight will be interesting to see what the diurnal increase in convective activity will bring.

 

[Jim Leonard]

If there is any vertical shear it would be slightly from the east. The center is a very short distance east of the coldest cloud tops as of 20Z.
Light east shear is much more favorable in the long term for development than any westerly shear. It is easier for flow at all levels to eventually become alligned if you start out with east shear in the atlantic basin.

 

[MClarkson]

unfortunatly it looks like some models(gfs, canadian, nogaps) prog a bit of westerly shear over the islands for day 3-4. Not a dreadful ammount, the GFS has the least and keeps it a bit north, but something to watch for, if this disturbance is still around then.

 

[Jim Bishop]

This thing's got a good mid to upper circulation, but it needs a surface low and deeper convection. It seems to be moving a bit too fast right now, but it's about to hit some warmer waters, so it may flare up more tonight. Maybe it'll strengthen just enough to give us a TD. The Euro & Canadian sure think it will (though the Canadian likes to develop everything, and the Euro developed this wave over the weekend as was obviously wrong).

The real test will be if this thing hangs on once it reaches the wind shear battle grounds of the Eastern Caribbean.

 

[Blake Michaleski]

I would say it has definitely got a mid level cyclone but there are apparent signs of an upper level anticyclone trying to develop. After careful IR imagery analysis, it looks as if there is at least some outflow aloft in all but the SE quadrant now.


Latest IR loop is now showing a fairly decent blowup of convection to the east of the apparent center.

 

[Blake Michaleski]

Well that's a nice nocturnal convective blowup!

[edit: (1:37am) Nocturnal convection is still increasing some/maintaining itself... We'll see TD4 tomorrow I'm quite sure... It would be td3 but the system to the NNW of Bermuda just got TD3 status]

 

[Matthew Crowther]

Looks like this thing is now pretty much dead in the water (pun intended).
Maybe enough of a wave can hold together for something to happen by the time it reaches the western Caribbean, but I see very little hope for any significant development before then. Sorry Jim

 

[Derrick Herndon]

Not dead but struggling. Barbados reported sustained at 30G50 kts earlier in a squall and now has sustained at 26 kts. Recon has found a nearly complete circulation but the winds on the south side are very weak. Pressure was as low as 1006 mb but 1008 mb seems more likely which matches well with the winds at Barbados and their pressure of 1010 mb.

Convection has had a hard time maintaining any organization which is not unusual of a fast mover like this.

Climatology is against further development in the E. Carib as the system may start accelerating, unducing further shear on the system.

 

[MClarkson]

agree, global models prog a bit of westerly shear and the gfdl and hwrf have been consistant with not developing the system.

 

[Martin North]

Invest 99L

Well despite everything it's convection has expanded greatly overnight. She's sitting there holding together nicely with apparent signs there may possibly be an LLCC buried in there.

Recon was brought forward and despatched...and is enroute atm for a closer look.

 

[Stuart Robinson]

I am currently in the extreame South East Dom Republic (on a family hoiliday) and just logged on to check the weather - Unable to throw together a forecast due to the intermittent connection that I have at this hotel !!! - I might pack Alison off home to England and set myself up further West *if* this system can hoild together - I would not mind an summary of the situation as I can not loop my normal model plots

Thanks in advance

Stu

 

[Jim Leonard]

Hi Stu,
I wouldn't hold on much hope for this system, it is imbedded in a strong low level flow which is typical for this time of year in the area that this system is at right now. It is extremely rare to see one like this one do anything, I've seen too many of these. Maybe when it gets to 80W but not before. Late August is another thing, we should see a much better chance for a big hurricane there.
Where are you in the Dominican Republic? What hotel? Do you have some internet? I think that island is going to get something big later this season.