http://www.ssd.noaa.gov/PS/TROP/DATA/RT ... -loop.html
Notice the circular outflow that is developing over the storm? This is indicative of an anticylcone developing at the upper levels. This promotes divergence in the upper levels...and just as importantly convergence at the low levels.
In turn...Irene appears to be responding with banding features becoming more and more evident. I wouldn't start the rapidly strengthening thread yet
