Gustav is undergoing rapid intensification tonight. Unsurprising, given that it has finally freed itself of the grips of those mountainous islands in its path...while at the same time hitting a swath of increasingly deep, very warm SSTs...
Outflow is abundant in all quadrants, yet a little bit pinched to the northwest and west.

Gustav will probably be declared a major hurricane by 8AM, and perhaps much sooner. Pressures are falling appreciably tonight. The most recent vort fix has Gustav down to 965mb, and still falling. Chances are high that Gustav crosses western Cuba, or just left of there, at Cat 2 or higher. There is some question tonight as to how much the restricted outflow to its northwest and west may begin hampering or even reversing intensification. Furthermore, in the near-term, there were some earlier hints of a second eyewall trying to form. An eyewall replacement cycle before crossing by/over Cuba could put a temporary, or not so temporary, dent in its intensity.

Of perhaps more concern, the radius of hurricane-force winds has been steadily expanding. Gustav is without doubt in the process of trying to become a large and powerful major hurricane, like Katrina was. On an unadjusted basis, Objective Dvorak Technique also indicates that Gustav is on its way to becoming a Cat 3-4 this morning. Once a major hurricane, provided that northwesterly shear remains contained, Gustav is likely to hold within a range of Cat2 to Cat5 until landfall. A stronger Gustav may make landfall closer to New Orleans, and a somewhat weaker Gustav may tend to make landfall farther west of there.

Barring an unpredictable eyewall replacement cycle or more shear than anticipated, Gustav probably maintains in the 110 to potentially as high as 175 MPH range for the duration of the next 60 hours or so, and a track a little on the northeast side of the current cone, at least for a while, seems more plausible. Towards the end of Day 3 or 4, Gustav may shunt southwestward in response to (the possibility of) a strong blocking high building into the middle of the country. Should this type of scenario verify, the central gulf coast may take many hours of pounding, wind-driven rain and incredible storm surge before Gustav then crawls around either inland, along, or just offshore of the upper-Texas coast. This scenario is a very ugly possibility, and unfortunately, an increasingly possible one.