INVEST 99L,East of Windwards

[cheezyWXguy]

Taking bets now...no jk...but we should make a poll about whether we think this could develop or not

[knotimpaired]

What are everyone's theory about African Dust?

We have not seen Puerto Rico which is about 7 miles away for weeks and weeks.

Today it is as clear as a bell and we can see buildings.

Rumors down here say that if the African Dust settles then a "storm is a brewing".

But this system seems way to south for that. Any idea what and if the Dust has to do with the storm tracks?

[canetracker]

Taking bets now...no jk...but we should make a poll about whether we think this could develop or not

I, for one, would vote that it is questionable for development. I do, however, think it is indicative of signs of things to come for mid to latter August and Septmeber. Yesterday evening this area was just a convective wave along the ITCZ and all of sudden it spun up.
99L bears watching but my main concern is not so much this area, but the pattern of development it is pointing to for the remainder of the season.

[RL3AO]

Unless it has some crazy blowup tonight, I don't know how well tomorrow will go.

[TexWx]

Seems as if the circulation is just running away.

[philnyc]

What is the Diffrence between DSHP and SHIP because they are different at 120hrs out with DSHP 62kt and SHIP at 77

Where's the dry air? Here is the GFS Global forecast for tomorrow afternoon (2007-07-31 at 18Z), with 99L's position annotated with red circle:



Where is everybody finding mid-level dry air?

[canetracker]

What is the Diffrence between DSHP and SHIP because they are different at 120hrs out with DSHP 62kt and SHIP at 77

Where's the dry air? Here is the GFS Global forecast for tomorrow afternoon (2007-07-31 at 18Z), with 99L's position annotated with red circle:



Where is everybody finding mid-level dry air?

I really look forward to your posts. Although, I can't answer your question, I do have a question for you. Why do your charts show moisture when the water vavor loop shows dry air? Is the water vapor showing surface level? Just trying to learn and thanks in advance for your reply.

[philnyc]

we are not seeing chantal on its way. The thing is light years away from TD status. That convective blow up is not even associated with the MLC, but appears to be related to some convergence east of it. Yes, a center could reform it the convergence can persist for about 24h... but that would slow development even more.

"Yes, a center could reform if the convergence can persist for about 24h... but that would slow development even more."

Hi Derek!
Can you explain that last statement? Why would a reformed center slow down development?

Phil

[Thunder44]

I like the anticylonic outflow aloft. I think it has a decent shot of developing over the next few days.

[btangy]

I would be extremely careful with the GFS analysis or any analysis/reanalysis' mid-level humidity over the tropical oceans. It is notorious for being one of the most uncertain variables and is subject to some potentially large errors. Satellites can't resolve mid-level moisture well and there are no radiosondes obviously to constrain the model 'first guess.'

[TheRingo]

we are not seeing chantal on its way. The thing is light years away from TD status. That convective blow up is not even associated with the MLC, but appears to be related to some convergence east of it. Yes, a center could reform it the convergence can persist for about 24h... but that would slow development even more.

"Yes, a center could reform if the convergence can persist for about 24h... but that would slow development even more."

Hi Derek!
Can you explain that last statement? Why would a reformed center slow down development?

Phil

maybe this new center is the wave detaching itself from the itcz.

[skysummit]

I can't wait to see what the morning holds...if anything.

[Derek Ortt]

new center would take some time to form; tus, slowing development

As for the GFS model analysis, it is totally WORTHLESS. Unless there was a change, the GFS does NOT assimilate humidity data. The Barbados sounding showed air far drier than anything suggested by GFS

[hurricanefloyd5]

looks like the center shiftedcloser/near the thunderstorms now!!!!!!!!

[RL3AO]

Still not even close to being a depression. It has a lot of work left to do.

[Ivanhater]

[Extremeweatherguy]

I still say give it a few days. It likely will have a much better chance once it reaches the central/western Caribbean.

[philnyc]

What is the Diffrence between DSHP and SHIP because they are different at 120hrs out with DSHP 62kt and SHIP at 77

Where's the dry air? Here is the GFS Global forecast for tomorrow afternoon (2007-07-31 at 18Z), with 99L's position annotated with red circle:


Where is everybody finding mid-level dry air?

I really look forward to your posts. Although, I can't answer your question, I do have a question for you. Why do your charts show moisture when the water vapor loop shows dry air? Is the water vapor showing surface level? Just trying to learn and thanks in advance for your reply.

Thanks, canetracker!
The water vapor loops most people use are really showing UPPER LEVEL water vapor which has little to do with tropical development. Satellites that measure radiated energy from upper level moisture often "see" only that - the upper levels, because that upper level radiation masks any radiation from the mid and lower level water vapor beneath it. So the energy from the middle and lower levels is never seen.
Since it is water vapor in the middle levels of the troposphere that are critical in helping a developing disturbance or even a strong one to intensify, you need to make sure that the water vapor sat you're looking at is middle level. This season, CIMSS added a really good satellite view of water vapor (I suspect because so many people were mistakenly confusing upper with mid-level). Here's the link:
http://cimss.ssec.wisc.edu/tropic/real-time/wavetrak/winds/m8wvmid.html

The only unfortunate thing about it is that it still doesn't give you "exact" numbers to make decisions by. That's why I love the ARL REAL system where you can make maps like I did above. Here's the link:
http://www.arl.noaa.gov/ready/cmet.html

It takes a little practice to use it, but it's totally worth it. For the tropics, I prefer the GFS global model (drop down menu is there). You will visually know what's really going on and what's forecast to happen, rather than have to picture it in your mind.
If there's one thing I'd like to see happen here with all of these discussions, it would be to stop seeing that upper level water vapor chart. If I didn't have anything else, I'd look at it, but why bother when we have these new, better tools?

[CrazyC83]

Still not even close to being a depression. It has a lot of work left to do.

Yep, it isn't even a low right now even though it has some decent convection. But plenty of time to develop. 98L will be named first if it does.

[PTrackerLA]

This new flare-up keeps things somewhat interesting with this system. As others have stated, I can't wait to see what it looks like in the morning. Development will likely be very slow but IMO, if it can keep somewhat of an identity to make it into the central and western Caribbean all bets are off.