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Posted: Mon Aug 13, 2007 10:23 am
by Caribbean Traveler
NHC has classified African depression as suspected earlier. Easterly winds aloft are shearing this system some, but won't be long before it will be named T.S. Dean.

All systems go for this one to strengthen - possibly into a major hurricane in a few days.

Models will update later today. The trend over the last few runs is to take it toward the islands. Stay tuned.

Posted: Mon Aug 13, 2007 12:09 pm
by Caribbean Traveler

Here we go again. As I had mentioned in a previous thread, it is way to early to estimate the long term track. The new GFS model now has the tropical cyclone moving up the east coast - similar to what it did 4 or 5 days ago!

So far Mexico, Houston, New Orleans, Miami, Charleston and the east coast have been solutions for the target of this system. :shock:
We don't know where the weakeness in the subtropical ridge will form at this time.

Posted: Mon Aug 13, 2007 3:45 pm
by Caribbean Traveler

Shear looks a little less. Heavy showers are building over the center. NHC may name this one soon - Dean.

Posted: Tue Aug 14, 2007 1:36 am
by Caribbean Traveler
Still classified as a depression. NHC tends to be conservative when a system is still far into the Atlantic. It appears to be boardering on a minimal tropical storm.

It is still fighting easterly shear which should lessen the next few days allowing for further development. Newest models tend to take system toward Leewards then more in a northwesterly direction to a position off the southeast coast by the middle of next week.

Posted: Tue Aug 14, 2007 9:35 am
by Caribbean Traveler

Visible satellite imagery distinctly shows the depression still being sheared by e/ne winds aloft. With that being said, it still has a very well defined low level circulation and deep convection on the southwest side.

Shear is still expected to relax and development to occur. It the depression was close to the U.S. NHC would have named it by now. It still appears to be a minimal T.S.

Models are still consistent in taking the depression toward the islands then starting to turn it more wnw near the Leewards. The final destination is still unknown. If the ridge stays strong it is possible for it to stay south and eventually get into the Gulf. If a weakness in the ridge develops, anywhere along the east coast will be at risk. The third scenario would allow it to recurve and stay off the coast.

Posted: Tue Aug 14, 2007 11:20 am
by Caribbean Traveler
Officially TS Dean with the 11am advisory

Posted: Tue Aug 14, 2007 12:20 pm
by Caribbean Traveler
New GFS model now is taking Dean across the islands into the Gulf then toward Texas. It has changed every single model run for days now. That's why there is no confidence in the models yet. BTW, the longer it takes to develop, the farther west it is going to get.

Posted: Tue Aug 14, 2007 6:26 pm
by Caribbean Traveler
Tuesday Evening

Northeasterly wind shear has not allowed Dean to further develop today. Latest satellite imagery indicates Dean is holding its own but not strengthening yet. This is actually not a good scenario. With the delayed development, it will allow Dean to move farther west. Models take Dean through the lesser antilles then eventually into the central/western Gulf.
Keep in mind that the forecast models have been erratic so far.

Posted: Wed Aug 15, 2007 1:33 am
by Caribbean Traveler
Wednesday AM

Overnight satellite imagery suggest that Dean is getting better organized. Even though it is hard to tell, it seems as though the convection is now over the circulation center. This means that the shear is weakening.

The GFS has takes Dean into the Gulf and eventually to Louisiana by the middle of next week. It has done this a couple of runs in a row now. It is still way to early to "hand your hat" on something that far out. Look for continued strengthening as it heads toward the islands by later this week.

Posted: Wed Aug 15, 2007 9:47 am
by Caribbean Traveler

Quickscat and visible imagery confirm that the convection has moved over the center of circulation. Shear has weakened so further strenghtening should continue. No big change to forecast in the near term, Dean is still heading toward the islands in the gerneral direction of Barbados.

GFS run from overnight now keeps Dean in Mexico. Again, this shows that NO tropical cyclone track can be predicted in the long term. A new forecast will be out during the afternoon.

Posted: Wed Aug 15, 2007 12:24 pm
by Caribbean Traveler
The new GFS still keeps the tropical cyclone south into Mexico by the middle of next week.

Posted: Thu Aug 16, 2007 1:38 am
by Caribbean Traveler
Thursday AM

Dean likely will be upgraded to a hurricane probably at 5am, if not shortly after.
Satellite imagery shows banding now developing as well as deep convection over the center of circulation.

Hurricane watches have been posted for some of the lesser antillies. The new GFS still keeps track south. The past several runs have not changed much. It appears that the subtropical ridge will stay strong north of the system. The weakness in the ridge will continue to move west with minimal impact. If this scenario plays out it will be good for the U.S. and bad for the Caribbean and Mexico. The later part of the track is still uncertain since that is still about 5 or 6 days out.

Posted: Thu Aug 16, 2007 10:38 am
by Caribbean Traveler
Thursday Midday

As expected, Dean is gaining strength. Top winds are estimated near 90. The Hurricane Hunters will investigate shortly so we have a better idea what the wind speed actually is.

Satellite imagery continues to show banding and cloud top cooling... all relating to better organization.

On it's present course it should come very close to Martinique or St lucia.

Models are staying consistent with the official NHC track - a mirror of the GFS. The last European actually shifted slightly farther south with a landfall in Belize or the Yucatan. The GFS continues with a double Mexico landfall....Yucatan and northeast Mexico.

Posted: Thu Aug 16, 2007 4:39 pm
by Caribbean Traveler
Thursday Afternoon

Latest NHC track takes a powerful Dean over the Yucatan. Models are in good agreement. The European keeps tropical cyclone a bit farther south, so Dean's 2nd landfall would be on other side of bay of Campeche instead of Northeast Mexico south of Brownsville Texas.

Posted: Fri Aug 17, 2007 1:34 am
by Caribbean Traveler
Friday AM

Dean will be by passing the lesser antillies Friday morning. The eye of Dean should move over St Lucia and Martinique. That's where the strongest winds will be found, especially over higher terrarin. Maximum sustained winds with the 2am NHC advisory are still 100mph. That seems a bit generous, especially since the recon pressure showed 976 MB. Unless Dean strengthens over the next few hours, I expect 100 mph mainly in gusts.

The forecast models remain very persistent. Most models take Dean to the Yucatan. The European is farther south with Dean near the Mexico and Belize border then over the bay of Campeche. The GFS is the farthest north. Two landfalls - one of the Yucatan and another in northeast Mexico south of Browsville, TX.

All in all, not much change in forecast thinking today.