ATL: TROPICAL DEPRESSION BONNIE - DISCUSSION

[hurricaneCW]

Well since most of Florida is suffering from an intense drought, a tropical storm would have probably been a good thing. So after days of watching this wave, it's probably not even going to develop, talk about anticlimactic. I'm hoping at least 98L develops so we can finally have Bonnie.

http://www.accuweather.com/blogs/weathe ... rought.asp

[brunota2003]

Dont need a tropical storm to bring lots of rain, or even a TD for that matter. A wave can produce just as much rain, given the right set up.

[Vortex]

Not making any compariosons between storms obviously but I remmeber the ULL that deloped to the NW of andrew and nearly destroyed it.....Thereafter ridging built in and the rest is history..

Excerpt from TPC on Andrew when he struggled:

Satellite images suggest that Andrew produced deep convection only sporadically for several days, mainly in several bursts of about 12 hours duration. Also, the deep convection did not persist. Instead, it was stripped away from the low-level circulation by the strong southwesterly flow at upper levels. Air Force Reserve unit reconnaissance aircraft investigated Andrew and, on the 20th, found that the cyclone had degenerated to the extent that only a diffuse low-level circulation center remained. Andrew's central pressure rose considerably (Fig. 2 [87K GIF]). Nevertheless, the flight-level data indicated that Andrew retained a vigorous circulation aloft. Wind speeds near 70 kt were measured at an altitude of 1500 ft near a convective band lying to the northeast of the low-level center. Hence, Andrew is estimated on 20 August to have been a tropical storm with 40 kt surface winds and an astonishingly high central pressure of 1015 mb

[xcool22]

SAB

2110N, 7290W

DT=2.0 BO CBND MET=1.0 PT=1.0 FTBO PT PA=30 NMI

[Stormcenter]

The yo-yo posts continue.
It is going to develop.
It's not going to develop.
It is going to develop.
And so on.

I've been saying from the get go 97L was going to have
a hard time becoming something significant and I see nothing
to make me think otherwise this evening. We all know the models
have issues at times with every developing or established TS. Some
just do a better job with some storms then others and vice versa. But the
common thing with 97L is that ALL of the models seem to agree that
97L won't turn into to much if it does develop. Yes things can change but
so far they haven't. IMO

[hurricaneCW]

Well it's never say never when it comes to the tropics. I guess we'll see what tomorrow brings for both systems.

[ConvergenceZone]

The yo-yo posts continue.
It is going to develop.
It's not going to develop.
It is going to develop.
And so on.

I've been saying from the get go 97L was going to have
a hard time becoming something significant and I see nothing
to make me think otherwise this evening. We all know the models
have issues at times with every developing or established TS. Some
just do a better job with some storms then others and vice versa. But the
common thing with 97L is that ALL of the models seem to agree that
97L won't turn into to much if it does develop. Yes things can change but
so far they haven't. IMO

I think most people are on the side of the fence of it NOT developing than there were last night, and that's probably because it's running out of
time as every hour passes and it's not showing any signs of moving away from the ULL into a better environment. I don't see honestly how it can develop, as
it has everything going against it. It can still form into a depression right before landfall though IF the shear abates, but that's a big "If"

[thetruesms]

Well, as I look at things tonight, I'm really wondering if that shear is going to drop off tomorrow or not. Possibly not. 97L may have just too much against it for a great chance of development now. I see the models all shifted west to Louisiana, probably more likely if it doesn't develop. My latest track was into the Grand Isle area of Louisiana Sunday afternoon, but it may just be a big rain event for Louisiana.

Yeah, my thoughts earlier were really dependent on that shear abating to something more manageable. If it does, I still think we can see Bonnie . . . but if not, it looks just this is going to be a stunted mass continuing in this cycle.

Well since most of Florida is suffering from an intense drought, a tropical storm would have probably been a good thing. So after days of watching this wave, it's probably not even going to develop, talk about anticlimactic. I'm hoping at least 98L develops so we can finally have Bonnie.

http://www.accuweather.com/blogs/weathe ... rought.asp

ugh, two weeks without rain is not a drought. You go back to the month-to-date precip, and a lot of that area is much closer to normal, with some spots even above normal. Go back to year-to-date, and a lot of that area is above normal, and everywhere is within 75% of normal.

Here's the Florida drought monitor - just a small sliver of the Panhandle that falls into "abnormally dry".

[Blown Away]

The yo-yo posts continue.
It is going to develop.
It's not going to develop.
It is going to develop.
And so on.

I've been saying from the get go 97L was going to have
a hard time becoming something significant and I see nothing
to make me think otherwise this evening. We all know the models
have issues at times with every developing or established TS. Some
just do a better job with some storms then others and vice versa. But the
common thing with 97L is that ALL of the models seem to agree that
97L won't turn into to much if it does develop. Yes things can change but
so far they haven't. IMO

I guess you need to define what you consider a "significant event". Very few people where saying SFL was getting a hurricane, I think most realized this would likely be a weak TS at best. IMO, 97L looks the best it has so far and I know that is not saying much. Finally deep convection near the "LLC" and I am wondering if the convection has spread a little west of the "LLC"?

[canes04]

ULL appears to be winding down as High pressure builds in.
This may finally have a chance to form tonight.Tomorrow should be interesting.

[Recurve]

Using best track I get 13.6 knot movement (326 nm over 24 hours) from 7/20 8pm EDT to 7/22 8pm EDT.

What do you all think of tonight's convection and effects of shear? Last satellite image seems to have suddenly popped into an appearance of consolidating, even wrapping some?

[AdamFirst]

ULL appears to be winding down as High pressure builds in.
This may finally have a chance to form tonight.Tomorrow should be interesting.

The same was said last night too

I'd laugh if 97L pulled a fast one on us and waited until it reached the Gulf Stream to become Bonnie.

[Stormcenter]

IMO I consider any "hurricane" a significant event and I was referring
to the possible strength of 97L if and when it would make a
second landfall. I don't think it will be anything more then a TS
when it crosses S. FL. assuming that still happens. We shall see.

The yo-yo posts continue.
It is going to develop.
It's not going to develop.
It is going to develop.
And so on.

I've been saying from the get go 97L was going to have
a hard time becoming something significant and I see nothing
to make me think otherwise this evening. We all know the models
have issues at times with every developing or established TS. Some
just do a better job with some storms then others and vice versa. But the
common thing with 97L is that ALL of the models seem to agree that
97L won't turn into to much if it does develop. Yes things can change but
so far they haven't. IMO

I guess you need to define what you consider a "significant event". Very few people where saying SFL was getting a hurricane, I think most realized this would likely be a weak TS at best. IMO, 97L looks the best it has so far and I know that is not saying much. Finally deep convection near the "LLC" and I am wondering if the convection has spread a little west of the "LLC"?

[Blown Away]

Using best track I get 13.6 knot movement (326 nm over 24 hours) from 7/20 8pm EDT to 7/22 8pm EDT.

What do you all think of tonight's convection and effects of shear? Last satellite image seems to have suddenly popped into an appearance of consolidating, even wrapping some?

97L seems to have slowed back down to a crawl again after it sprinted away from Hispaniola this afternoon. If 97L improves over night from it's current status it could be near TD status tomorrow morning. I think it's now moving much less than 13.6 kt's.

[boca]

On another board someone posted that a cruise ship reported winds of 60mph around the Turks and Cacois islands.

[thetruesms]

ULL appears to be winding down as High pressure builds in.
This may finally have a chance to form tonight.Tomorrow should be interesting.

It also looks to elongating some, which is keeping that shear zone from clearing out of the area very quickly, which could be an issue if that continues.

[Air Force Met]

I guess you need to define what you consider a "significant event". Very few people where saying SFL was getting a hurricane, I think most realized this would likely be a weak TS at best. IMO, 97L looks the best it has so far and I know that is not saying much. Finally deep convection near the "LLC" and I am wondering if the convection has spread a little west of the "LLC"?

I agree. I think too many people are killing this off prematurely. I think we see Bonnie out of this. Hispaniola did a number on the southerly inflow...much the friction with the island imparted a fair amount of spin to the system...this has increased the surface convergence significantly and sharpened the wave.

I think the ULL will get into a more favorable position tomorrow and help ventilate the system. It will still be getting sheared...but I don't think it will be as bad. Instead of SW'ly winds aloft...will probably be more SE'ly and a little lighter.

It also appears the ULL is shearing out a little and diving WSW...and this will certainly place 97L in a more favorable environment.

I don't see anything super powerful out of this. I think the ULL will be a thorn in development for a while...and they low heat content in the Gulf won't help. Looks to me like a landfall eventually near Louisiana...maybe MS....depending on when it finally gets its act together. I've been telling my staff that the models taking it over the extreme NE Gulf and even FL were out to lunch...so I am glad to see them move a little west. Their problem was the GFS was decoupling the system (like it tried to do with Alex)...and they were taking it to fast to the NW.

The one fly in that ointment is those earlier runs could be right but for the wrong reason. In sheared systems you have a tendency to get center reformations to the north towards the convection...or the LLC gets pulled towards the convection. If the shear doesn't relax enough...this is certainly a possibility.

Time will tell.

[george_r_1961]

It will be moving into conditions best described as "not unfavorable". With that said we have a system that is over warm water and that could eventually end up in the part of the GOM that has spawned some monsters. In a nutshell: Lets not let our guard down for an instant. Not with this one or any system within easy striking distance of land, no matter how pathetic they look.

[CourierPR]

Using best track I get 13.6 knot movement (326 nm over 24 hours) from 7/20 8pm EDT to 7/22 8pm EDT.

What do you all think of tonight's convection and effects of shear? Last satellite image seems to have suddenly popped into an appearance of consolidating, even wrapping some?

I noticed this too but thought I must be going insane from looking at one too many satellite loops. That said, it does look like it might be attempting to close off a LLC.

[Air Force Met]

ULL appears to be winding down as High pressure builds in.
This may finally have a chance to form tonight.Tomorrow should be interesting.

It also looks to elongating some, which is keeping that shear zone from clearing out of the area very quickly, which could be an issue if that continues.

I agree. Its shearing out with a piece of the energy diving WSW. This will probably spin up another upper level low to the SW of where it is now. That will place 97L under SE'ly shear...which isn't so bad.

The one thing we cannot count on is what the pipcture will look like in 2 days. Upper level wind forecasts are so bad with these ULL's...it could be well SW of the system and providing great outflow...or it could stay west of it and shear it to death. No confidence at all in the upper wind forecast.