8:50 AM EDT 14 Aug 2007 Update
Caribbean disturbance (90L) is still getting its act together and may become a depression later today, recon is going out later today as well.

TD#4 is a bit better looking this morning, and models are trending back west a bit, once again increasing chances that the storm could affect the leeward islands.

Beyond that, still too early to tell, but it would be prudent to watch it.

It is very likely we will see TD#4 become a Tropical Storm late today, but right now Dvorak numbers (Satellite windspeed estimates) do not support a tropical storm.

More to come later.

2:45 AM EDT 14 Aug 2007 Update
Neither system has developed much more since yesterday, although potential for 91L to develop today (the 14th) is still there. TD#4's convection hasn't been around the center of circulation lately, so it's further development is in check. The forecast track has shifted slightly north, reducing the potential impact in the Leeward islands, but the errors are still large.

Beyond the islands, it's still much too early to call. The best case would still be a curve away from land, and it is looking less likely this system will go into the Caribbean now. Still those in the area will want to watch because of the possibility for track errors at that range.

We will continue watching the progress on it.

91 didn't have enough last night to make it into a depression or storm, but it is looking better on satellite in the early morning hours. Chances are still high that it will develop sometime later today. Track thoughts haven't changed much on it either.

1:20 PM EDT Update
A Tropical Cyclone Formation Alert has been issued for 91L in the gulf, meaning a depression or Tropical Storm is likely to form there within 24 hours.

11AM EDT Update
Tropical Depression Four advisories are out, the NHC is currently projecting a track through the Leeward Islands as a category 1/2 hurricane later in the week. However, the margin of error is pretty high this far out, but those in those islands should monitor this system accordingly.

Tropical Storm Dean is expected to form from TD#4 later tonight or tomorrow. (This may change to Erin depending on the status of the Gulf System)

Over in Hawaii Hurricane Flossie is projected to move south of the Islands, but a Hurricane Watch is up for the Big Island of Hawaii. More information on Flossie at {{CPHC}} and in this thread.

To reiterate as well for the system in the gulf, those along the western coast of the Gulf of Mexico should pay attention to the system developing in the Gulf (91L), it could form into a depression or more later today or early tomorrow.

10AM Update
West Caribbean System is now being tracked as 91L, and this system has a chance to finally develop again. Things are about to get really busy. Early models suggest 91L may be headed to extreme southern Texas. It doesn't appear it will have the time to strengthen into anything too major, but is indeed worth watching -- after all it is August and water temps in the Gulf are very warm.

Those in the western Gulf Coast should be watching this, as it could form into a depression later today or early tomorrow. Aircraft recon is scheduled to visit this area tomorrow.

More to come later on it and TD#4 as it comes in.

Original Update
Tropical Depression #4 has formed in the far eastern Atlantic from the wave called 90L, and is still moving west. The first advisories should begin at 11AM EDT.

Plenty of time to watch, the prior update is posted below which explains the thinking so far, which hasn't changed much.

More to come later.

{{StormCarib}}

{{StormLinks|TD#4|04|4|2007|1|Tropical Depression Four (Far Eastern Atlantic)}}

{{StormLinks|91L|91|5|2007|2|91L (West Carib/SE Gulf Disturbance)}}

Older Updates
9AM 13 Aug 2007 Update
Indications from Dvorak satellite estimates suggest that 90l may now be a tropical depression, advisories may start as early as 11AM EDT.

5:20PM EDT Update
The wave off Africa has been designated invest 90, and is being tracked by the NRL as such. Model runs have began on it, and I'm not liking what I see. Westward ho--for a good while, 90 L will likely be this year's first long track Cape Verde system. (really the first since Ivan in 2004--this does NOT mean I think it will take a track like Ivan, however)

Chances for Tropical Development of Wave off Africa (90L) In Next 3 days (Updated 9AM 12 Aug - TCFA Issued)
Code:


(forget it) 0 1 2 3 4 5 6 7 8 9 10 (sure thing)
            [--------------*-----]

It has the potential, if it persists, to become a depression over the next few days. The stronger it gets further east out in the Atlantic, the more likely it will recurve away from the Caribbean and potentially out to sea. Conversely, and more likely, the weaker it remains longer, the more likely it will continue a westward track.

As mentioned, this is the first potential Cape Verde storm of the season, and it should be a reminder to those in the Caribbean to be prepared. Even though we have a good number of days to watch 90L.

Remember it takes a few days for models to get a handle on newly formed systems, and data out in the Central and Eastern Atlantic for upper level winds isn't all that great. Many waves off Africa die down a bit after the initial phase, so it is possible the system will lose it, and hopefully it will. However conditions are good enough to hold it together for the foreseeable future.

Those in the lesser Antilles will want to watch for it by next late next week into the weekend (16-18th) , there is a decent chance a storm will be near or over there at that time. As such soon thereafter others in the Caribbean may need to watch.

For those along the east coast of the US, i'd watch it, if would be just about a week and a half out (21st) for it to get anywhere close to us, assuming it doesn't fall apart or curve out to sea before then.

Now for the realm of speculation, based on models...

What we don't want is the scenario given by some of the super long range models, The long range GFS earlier today had the system heading toward South Florida (Also EMCWF), and later into the Gulf near Houston, ( See this and This)
I'm sure it'll be back somewhere else at the next runs around midnight. What does this mean? Nothing--models at that range are about the same as throwing a dart from a moving car on a dirt road, but it's another sign that the season is about to get active and that we must watch. Average error for models at that range is over 1000 (a thousand) miles.

Intensity wise, the first GFDL run on the system takes it to Hurricane strength by the time it gets to 40 degrees west. (Currently it is at 20 degrees West), the HRWF model brings it to a Category 3 hurricane before reaching the Caribbean.

It's more important for East Coast and Gulf Coast folks, just wait to see model trends, and do not take any one run of the long range models to heart right now. I certainly don't think much of them beyond Wednesday or so as worth anything,.

With that said, we'll definitely be watching it, and it's a good idea to check back during the week to see the updates with this system, especially if it develops into a named Storm. The next name up on the list is Dean. There are other indications that other storms may follow this one as well, which is not too uncommon for mid to late August.

Not to forget the West Caribbean System, it's closer to land and still not really moving much, it still needs to be watches as well, but it is less likely to develop.

Chances for Tropical Development of Disturbance in Western Caribbean
Code:


(forget it) 0 1 2 3 4 5 6 7 8 9 10 (sure thing)
            [-----*--------------]