Gulf of Mexico disturbance 92L spins up

A non-tropical low pressure area has developed in the Gulf of Mexico just off the coast of Mexico, about 300 miles south of Brownsville, Texas. This disturbance has been designated "92L" by NHC this evening, and does have a small chance of developing into a tropical storm. If it does develop, it would likely move north-northeast and strike the coast of Texas or Louisiana on Monday or Tuesday. The pressure has fallen significantly at Tuxpan, Mexico, and was 1005 mb at 7pm EDT. Winds over the waters just offshore the Mexican coast were as high as 40-50 mph in this morning's QuikSCAT pass, but were only 15-20 mph in this evening's 8:11pm EDT pass. A new QuikSCAT pass is due at 10am EDT Sunday. The satellite appearance of 92L has degraded markedly in the past few hours, with most of the heavy thunderstorm activity moving far east away from the center. There is very little shower activity associated with 92L visible on long-range Brownsville radar this evening. Unfortunately, the Mexican radar for this region has been down since September 3.

The disturbance is under about 15 knots of shear this evening, which is low enough to allow development into a tropical storm. However, the storm is moving towards an area of much higher shear (40 knots!), and this higher shear may cause significant trouble for the disturbance. Shear is forecast to drop significantly in the Gulf beginning Monday, so there may be a window of opportunity that day for 92L to grow into a tropical storm. I'm really not expecting this to become a tropical storm, but if it does, it would likely not have time to grow to more than a 50-mph storm.


Figure 1. Preliminary model tracks for the Gulf of Mexico disturbance, 92L.

I'll ba back with an update late Sunday morning.

Jeff Masters