What does the tropical blob in the Gulf mean for Texas?

In brief: A tropical low has developed in the northern Gulf, and it will move generally west toward Texas over the next couple of days. We assess what this means for the greater Houston region this week, which hopefully means some beneficial rains.

A tropical low is located off the coast of southeastern Louisiana. (NOAA)

Over the last day or so we have seen a low pressure system in the northern Gulf slowly develop. Thunderstorms associated with the low, designated Invest 97L, have become better organized overnight, but so far surface pressures (another indication of organization) have yet to drop significantly. So we have, essentially, a tropical blob sitting out there 100 miles or so south of the mouth of the Mississippi River.

With high pressure over the southern United States we can expect this tropical low to to generally move to the west or west-northwest over the next couple of days. This is likely to bring the system toward the upper Texas coast by midweek, which is to say somewhere probably between Galveston Bay and the Texas-Louisiana border. Of course, in the absence of a well-formed center, there remains some uncertainty in the track.

This cluster of ensemble forecasts shows the general expectations for the tropical low’s track this week. (PolarWx)

So something is coming toward the upper Texas coast, and it will likely reach land on Tuesday or Wednesday. Our baseline expectation is that this remains a tropical low pressure system or a depression, but there is a chance for development into a tropical storm. Surface waters are more than warm enough (sizzling actually) to support intensification, and wind shear is relatively low. So if the current system can develop some spin, it will have a chance to organize.

Should you be concerned? Not at this time. The system would be beneficial should it bring some much needed rainfall into the region on Tuesday or Wednesday, but these rains could just as easily fall to our east, over Beaumont or southwestern Louisiana. As for amounts, maybe 1 to 3 inches? It’s difficult to say with any confidence yet. Regarding winds and storm surge, we will keep an eye on things for you, especially with the tropical low so close to Texas.

More tomorrow.