We’re continuing to watch the development of a tropical disturbance in the Caribbean Sea, near the Yucatan Peninsula, that is moving toward the Gulf of Mexico. This system could play a major role in the Houston region’s weather later this week—or very little. But it’s something I think is definitely worth paying attention to.

Will it develop?

At present the system is a broad area of low pressure, but a lot of forecast models are bullish on its development into something akin to a relatively weak tropical storm over the next few days. The National Hurricane Center believes this, too, giving it a 90 percent chance of development into a tropical depression or storm during the next five days. (A hurricane hunter may investigate the storm later today). Although we can’t rule it out, this tropical system appears unlikely to reach hurricane strength, and therefore the primary threat will be a lot of rainfall.

Where is it going?

This is the key question, and one that remains difficult to answer. We can be reasonably confident the tropical system will slowly move across the Yucatan Peninsula today and Monday, and thne find itself in the southern Gulf of Mexico. But this is the easy part of the forecast.

From this point, the models diverge quite a bit (and have consistently done so during the last 48 hours). The GFS continues to develop the storm fairly quickly, and bring a tropical storm north, across the central Gulf of Mexico and into the northern Gulf of Mexico coast, between Louisiana and the Florida panhandle by early Wednesday. If we look at the GFS ensemble model locations for the center of low pressure on Tuesday night, they are clustered remarkably close to one another, suggesting the model has high confidence in the solution.

At the same time, the European forecast model is equally confident in slower movement of the tropical disturbance, and a weaker overall system. This scenario brings the storm toward northern Mexico or the Texas coast by Wednesday or Thursday with a fair amount of moisture. Here’s a look at that potential outcome:

As a general rule, the European forecast model does a better job than the GFS, and because the system remains disorganized, I think that increases the likelihood of a more westerly track across the Gulf of Mexico, toward Mexico or Texas, during the coming week. But we just can’t pick a winner yet, and probably cannot until the system moves into the Gulf of Mexico and develops a more organized center of circulation.

Implications

What we can say is that if the system moves north as the GFS model suggests, Houston will see minimal effects. That is because most of the “weather,” in this case the winds, rains and higher tides, are to the east of the center of this storm. Therefore even a landfall in Louisiana would mean little for Texas.

Conversely, if the system moves toward the central or southern Texas coast, the Houston area would be on the side of the storm with all the “weather,” which could mean a few inches of rain, or more. That remains our primary concern right now.

Posted at 8am CT on Sunday by Eric