Tropical weather analysis - July 7, 2010

Invest 96L has become significantly better organized this evening, with visible satellite animations depicting a well-organized system, with deep convection increasing near the center of circulation, which I estimate is located at 24N 93W. However, this isn't completely certain, because the center is clearly tucked underneath the deep convection, and isn't even partially exposed.

In addition, surface pressures appear to be low and falling within several hundred miles of the disturbance, and surface and buoy observations suggest that this system has a well-defined surface circulation. Station 42002, located in the western Gulf of Mexico at 25N 93W, isn't even in the deepest convection associated with 96L, and is already reporting sustained winds of around 22 mph, with gusts to around 28 mph. This suggests that sustained surface winds are likely near 30 mph within the deepest convection near the center. However, I should note that cloud top temperatures aren't particularly cold near the estimated center, only around -60C. This is likely due to passage of cooler water upwelled by Hurricane Alex. As 96L pulls away from this cold wake, however, it should be able to generate colder convection and subsequently intensify.

This system appears to have an upper-level anticyclone centered directly atop the estimated surface center. Obviously, this will guard it from any vertical shear. The 18z GFS keeps an anticyclonic environment within the vicinity of 96L over the next 24 hours. This should allow for continued intensification of the system, particularly after it pulls away from Alex's cold wake. All in all, a tropical depression appears to be imminent from this system. I am expecting this system to attain tropical storm status, peaking at 50 mph. Interests from northeastern Mexico to central Texas should carefully monitor the progress of this system over the next day or so. Regardless of development, locally heavy rainfall and gusty winds will begin to overspread portions of northeastern Mexico and southern Texas tonight and into tomorrow.

The track for this system is very straightforward. The current NW motion should continue for the next 6-12 hours, after which point a building ridge to the north should begin to impart a more WNW component of motion. This system should be inland in less than 24 hours, I'd say about 18-20 hours. I have the landfall location between Brownsville and Port Mansfield.