The rainbands have been moving into Texas since mid morning and continue to ramp up especially in deep south Texas. I noticed a special feature on radar at about 3:45, which seems to be the mid-level center (MLC).   Recon was out inside Don a few hours ago and lost winds on the southern side.  We look for west winds on the southern side of tropical cyclones to make sure that they are completely closed off. There were signs from recon that some back stacking and this loss of circulation had begun. This is concerning because of the proximity of land.  The MLC is much closer to land than the NHC monitored center is, which would make landfall as early as 6 to 7pm CT if the MLC works its way down to the surface. The MLC is just about due east of Brownsville while the LLC is east of Kennedy County, which is almost entirely ranching area. Lightning has been going wild near the MLC over the last few hours, although it has calmed down a bit now.  Lightning is often looked at as an early sign of intensification.

Nonetheless, Don has winds of 50 mph, and I do not expect any more intensification before landfall. Most of the tropical storm force winds regardless of center should be north of the Mexican Border, but a few heavier rainbands make it into extreme northeastern Mexico. Tropical Storm Warnings are in place from the Border to Matagorda at this time, and these will probably be allowed to expire over the next few hours.

I’ll update more in a few hours.