2:00 PM CST Update 27July 2011
90L has nearly a 100% chance to develop in the next 48 hours, more likely when the aircraft recon plane currently en route finds a circulation center.

Since landfall is expected around Friday night, it is very likely Tropical Storm or Hurricane Watches could be issued for Texas as early as the first advisory of the system.

Those along the Texas coastline (particularly south Texas from Matagorda southward into Northeastern Mexico) may need to enact plans tomorrow, so listen closely to local media and officials if and when watches/warnings are issued.

7:00 AM EST Update 27July 2011
The wave in the Northwestern Caribbean (90L), inow with a 70% chance for development in the next 48 hours, may develop today when aircraft recon verify it.

It appears to be moving west northwest and may cross over the tip of the Yucatan peninsula tonight, beyond that it has a chance to affect the western Gulf coast.

I would not recommend using the models to guide any particular future track at present, with the relatively small size of the system and lack of recon data, it appears models are all a bit too far north. Those in the Gulf coast from Corpus Christi/Matagorda southward into Northeastern Mexico are still in the highest probability for some affects with this system. If you are there, better review your preparation plans.

It is still too early to be any more specific than that because of the small size. Those further north into Western Louisiana will want to monitor it also, in case a weakness in the ridge forms.

For track, the single largest factor will be the ridge, any any weaknesses, it is expected that the ridge strengthens, keeping the system more westward than north. This lessens the chance for further north in the Gulf/Texas greatly. It is still worth watching for those until official advisories and forecasts on the system are made, however.

If it does develop, it will likely become Tropical Storm Don, and has a shot, with marginally favorable conditions, to become a hurricane. Given the usual methods, it could become a strong tropical storm, or Category 1/2 hurricane. There always exists the possibility in the Gulf for rapid intensification, and is a worry with smaller systems (They can rise and fall quickly) So it will need to be monitored closely for that, but that is not likely in this case since there is still a bit of dry air in the southern Gulf.

For now Cancun Yucatan will be dealing with some nasty weather and rain today, but nothing terrible. How much it organizes today will be limited on if it crosses the tip of the Yucatan or not.

Northeast Mexico, and the Texas coastline will want to monitor for official statements when/if this system forms. Based on current information, landfall timeline is Friday evening.

Cancun radar recording of 90L approach

Webcam Recording: Cancun Beach Palace roof looking north northeast along the beach.

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7:45 PM EST Update 26 July 2011

The wave in the northwestern Caribbean continues to look better into the evening, but still lacks a defined low level circulation, if one to form it could develop within the next 48 hours. The national hurricane center gives the system a 40% chance for development, and barring a definite center forming overnight, it is unlikely to be upgraded until recon aircraft verify this during scheduled for a mission tomorrow, reach it.

Those in the extreme northern Yucatan in Mexco, and South Texas from Corpus Christi/Matagorda southward into Northeastern Mexico still need to continue to watch this system very closely, and those in the rest of the northwest Gulf should monitor it as well.

Original Update
90L may not be over, it is still worth watching.

With the wave dealing with land interaction the last few days, development chances were about nil (For the near term that the hurricane center keeps odds on, 48 hours). However, since the wave seems to be organizing in the Caribbean south of Cuba, and generally heading west, or slightly north of west, chances are rising again

Negative factors include some dry air, a short term upper level low to the west, and current lack of a defined low level circulation, but on the other hand shear is not really a factor, and will be less so as time goes on this week. The Upper level disturbance will likely dissipate before the end of the day, so that negative factor will likely disappear too.

As for the wave itself and the National Hurricane Center, during the day development chances will likely rise, and if the convection continues to persist like it is in the northwest Caribbean, it could even develop before approaches the Yucatan in the northwest Caribbean.

Which means, for those in the Yucatan (Around Cancun/Cozumel), Northeast Mexico, and south Texas (south of Corpus Christi), watch this system closely.

It will likely pass over the Yucatan briefly, and then into the southern Gulf, with northern Mexico the most likely place to eventually deal with it. It will bring quite a bit of rain areas it passes over. Most likely on Friday. Intensity is difficult to gauge with the Yucatan, warm water, dry air, and Northwestern Caribbean, so it could range from a nice rainstorm to a named system. Since the potential is there for that, those in the Yucatan, Northeast Mexico, and South Texas will want to watch this closely this week.

The zone in the Northwestern Caribbean is known for very favorable waters for developing systems, and this wave will be moving over part of that.