The National Hurricane Center now gives “Invest 91L,” the Gulf of Mexico system that I mentioned yesterday, a better than 50% chance of becoming a tropical cyclone in the next 48 hours. The NHC issued a Special Tropical Disturbance Statement at 11:00 AM EDT, stating:

SATELLITE IMAGERY AND SURFACE OBSERVATIONS INDICATE THAT A LOW PRESSURE AREA HAS FORMED IN THE NORTHERN GULF OF MEXICO ABOUT 150 MILES SOUTH OF PENSACOLA FLORIDA. ENVIRONMENTAL CONDITIONS ARE MARGINALLY FAVORABLE FOR ADDITIONAL DEVELOPMENT…AND A TROPICAL DEPRESSION COULD FORM DURING THE NEXT DAY OR SO AS THE SYSTEM MOVES TOWARDS THE WEST. AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT IS SCHEDULED TO INVESTIGATE THE AREA THIS AFTERNOON. INTERESTS IN THE NORTHWESTERN GULF OF MEXICO SHOULD MONITOR THE PROGRESS OF THIS SYSTEM.

If it becomes a tropical depression, it would be T.D. #5. If it becomes a tropical storm, it would be named Edouard — assuming it crosses the 39-mph finish line before either of the waves over the Atlantic (which appears likely).

The Houston Chronicle’s Eric Berger has a lengthy post about this possible proto-Edouard, in which he writes:

It’s impossible to know for sure [where it will go], of course, as we’re dealing with an as-yet unformed system. But the computer models are fairly consistent in bringing something to the Texas coast between Corpus Christi and the Texas-Louisiana border by early Tuesday. …

Because any landfall would come so soon, there’s little time to prepare, and if anything does form it probably won’t do so until the last 24 hours or so before landfall. …

It’s important to stress that none of the computer models presently develop this system into anything more than strong tropical storm. … [But] hurricane intensity forecasting remains quite a poor science. The rapid intensification of systems such as Hurricane Humberto remains poorly understood. And sea surface temperatures in the vicinity of this system are warm.

With that being said, conditions in the upper atmosphere appear to be sufficiently scrambled around this system to work against rapid strengthening. So the best bet seems to be that the system will become a tropical depression or a tropical storm before landfall.

But at this point, no one can know.

That conventional wisdom — that 91L is unlikely to become a serious windmaker — is echoed by Alan Sullivan, who writes that “development into a hurricane is improbable,” and by Bryan Woods, who writes, “If this system does develop, it is unlikely to have time to become very strong. However, any tropical system impacting land can lead to heavy damage from inland flooding.”

Woods is right. However, in this case, heavy rain could be something of a blessing. As Berger writes: “a significant rain event is probably headed our way, and with any luck it will help break the severe to exceptional drought that is plaguing central and south-central Texas.” Here’s a map of 91L’s computer model tracks, and a map of the drought in Texas: