ATL: Tropical Depression Dolly

[Ed Mahmoud]

We'll see. I'm inclined to expect some slightly slower movement.

If it isn't too deep a system, it'll be embedded in fairly quick flow from the East at lower levels when it reaches the Caribbean.

Why I'd expect no strengthening, unofficially, while East of about Cuba in the Caribbean.

[KWT]

Hmm I think we will see some strengthening in the eastern Caribbean as it happens when and if it gets there of course!
We will have decent heat content, air should me pretty moist and the higher region of shear is further off to the west in the central part of the Caribbean according to the models I've seen.

[smw1981]

Great! Thanks! We're going on a little vacay to the DR and Jamaica on the 25th and would not like to have any guests!!

[Ed Mahmoud]

Hmm I think we will see some strengthening in the eastern Caribbean as it happens when and if it gets there of course!
We will have decent heat content, air should me pretty moist and the higher region of shear is further off to the west in the central part of the Caribbean according to the models I've seen.

I disagree, it is early in the season, and the Equatorial heat low over South America will speed this up to 20 knots or more.

I'd say steady state at best, strengthwise, between 60 and 75ºW. See 2003 Claudette, almost died in the Caribbean.


Now, later in the season, when that heat low fades, a well built system, like 1989's Gilbert, can strengthen in the Eastern Caribbean.

[Fego]

Great! Thanks! We're going on a little vacay to the DR and Jamaica on the 25th and would not like to have any guests!!

Geee... what a timing ... stay tuned smw 1981. I suggest to check the hotel or pkg cancelation policy, just fyi. You will win more than loosing if you know in advance the differents scenarios. I'm not saying it will hit DR, btw I prefer not to because I have family there. In fact, nobody knows where it will go.

[KWT]

I do understand what your saying Ed and as it happens i don't think it will strengthen all that much in the East Caribbean either but I think I was more thinking about your assumption it would stay weak, there is no reason why it can't become a minimal hurricane in the East Caribbean, we've seen it in July quite a few times before, granted I don't think it wil lbecome any stronger then that before it gets further west.

ps, I seem to recall Derek once saying that the speed of the system stopping strengthening is a bit of a myth?

[cheezyWXguy]

I do understand what your saying Ed and as it happens i don't think it will strengthen all that much in the East Caribbean either but I think I was more thinking about your assumption it would stay weak, there is no reason why it can't become a minimal hurricane in the East Caribbean, we've seen it in July quite a few times before, granted I don't think it wil lbecome any stronger then that before it gets further west.

ps, I seem to recall Derek once saying that the speed of the system stopping strengthening is a bit of a myth?

To an extent i can see that being a myth...but when it gets too fast, the mlc and llc can decouple, or it could produce the same result of strong shear. Ivan was the fastest hurricane Ive ever seen that was able to strengthen to a cat4 out in the catl, so i guess he was the rule of thumb for calling the theory a myth

[Gustywind]

000
AWCA82 TJSJ 141540
RWSVI

WEATHER SUMMARY FOR THE U.S. VIRGIN ISLANDS
NATIONAL WEATHER SERVICE SAN JUAN PR
1140 AM AST MON JUL 14 2008

A STRONGER TROPICAL WAVE HAS THE POTENTIAL TO MOVE ACROSS THE
LOCAL ISLANDS THIS UPCOMING WEEKEND...BRINGING INCREASING
SEAS...STRONG WINDS ALONG WITH SHOWERS AND THUNDERSTORMS.

[KWT]

Well Dean last year was moving at 20-25kts pretty much its entire life and yet it still was constant cat-4/5...however I do think that for weaker systems it matters far more because obviously it can cause trouble trying to close off the circulation on the southern side if its rushing westwards.

[Gustywind]

000
FXCA62 TJSJ 141629
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
1229 PM AST MON JUL 14 2008
MAIN INTEREST REMAINS FOCUSED ON A STRONG TROPICAL WAVE NEAR 43
WEST...WHICH HAS THE POTENTIAL TO BRING ROUGH SEAS...STRONG WINDS
AND INCREASED WEATHER TO THE FORECAST AREA OVER THE UPCOMING LOCAL
HOLIDAY WEEKEND.

[jasons2k]

It depends on how the speed of the system interacts with relative shear. A system can be booking along at a good clip but if the winflow is parallel or in-sync with the storm, then it won't decouple. That's usually not the case though.

Think of driving - driving 60mph into a 20mph headwind puts a lot more stress on the vehicle than driving 70mph with a 30mph tailwind.

[KWT]

Yeah thats true Jasons if you've got shear coming out from the west and the system is heading to the west that only increases the relative shear.

By the way this thread is now the 26th longest out of Atlantic tropical cyclones.

[cycloneye]

By the way this thread is now the 26th longest out of Atlantic tropical cyclones.

And its only a invest.

[Brent]

2pm TWO:

THUNDERSTORM ACTIVITY WITH THE AREA OF LOW PRESSURE LOCATED ABOUT
1200 MILES EAST OF THE LESSER ANTILLES HAS INCREASED A LITTLE SINCE
THIS MORNING. ENVIRONMENTAL CONDITIONS ARE FAVORABLE FOR FURTHER
DEVELOPMENT...AND THIS SYSTEM COULD BECOME A TROPICAL DEPRESSION AT
ANY TIME DURING THE NEXT DAY OR TWO AS IT MOVES WEST-NORTHWESTWARD
AT 15 MPH.

[KWT]

Yep Brent still agressive wording but with a get out clause there about the next day or two.

Cycloneye, that statement only counts if this becomes a TD because there have been invest threads get upto 50-100 pages before but because there is only a limited about of numbers to stop it from getting confusing I just used systems that got to TD strength and above...certainly a quick start though and if it does develop everything points towards top 10 IMO.

[HurricaneHunter914]

All it needs is one nice burst of convection over the center. Funny how both Bertha and 94L are having trouble getting convection over the center.

[Vortex]

Great structure compared to 24 hours ago..Also, we may get that deep convection to take place overnight tonight..Interesting 24H ahead.

[Thunder44]

It does look better organized then earlier today. It just needs more convection over the center. I think we need to give it another day.

[HurricaneHunter914]

Still no luck with convergence for 94L.

[vacanechaser]

Well Dean last year was moving at 20-25kts pretty much its entire life and yet it still was constant cat-4/5...however I do think that for weaker systems it matters far more because obviously it can cause trouble trying to close off the circulation on the southern side if its rushing westwards.

thats right.....however, the wind was that strong at most layers of the atmosphere... so the entire system moved together to the west.. the low level winds were blowing just as strong as the mis and upper level.. the ridge was strong and very thick.. thats why... if the low level is stronger or weaker, then the system can not vertically stack and it creates shear over the system... so it is not a myth in most cases..



Jesse V. Bass III
http://www.vastormphoto.com
Hurricane Intercept Research Team