Radar loops are generally only one hour long, particularly those from the NWS. Thus, they are not going to show forward speed all that well; movement on satellite is better for that right now. Overall, it's still going at a decent clip, but it's going to fluctuate up and down between 7-8mph and 14-15mph.

As for the "dry slot" on radar -- long-range radar through areas of heavy precipitation often suffers from what is called attenuation, where echoes may not be able to be detected at such ranges due to the heavy precipitation capturing all of the echoes sent out by the radar. That's more likely than not what is occurring in the last couple of radar frames at this time.

Conditions have begun to really deteriorate in Southeast Louisiana & New Orleans and will continue to do so through the night. The first well-defined feeder band is just off-shore, stretching from New Orleans to south of Pensacola along the extreme northern Gulf coast. Heavy rain, gusty winds, and isolated tornadoes are likely with this band. Future bands will only ratchet up the winds, rain, and the waves. Storm surges of 20' are not out of the question over a wide area from Mobile to SE Louisiana where the storm makes landfall.

At 7:45p ET, the storm is located 200mi. SSE of New Orleans and 130mi. due S of the extreme SE tip of Louisiana, moving NNW at between 8-11mph. The latest recon report shows a central pressure of 904mb, only 2mb higher than earlier this afternoon. This storm is likely to maintain itself over the course of the evening, aided in time by the diurnal convective maximum and warm waters off of the coast of Louisiana. It is a good bet that this storm will landfall as a ~165mph category 5 hurricane in SE Louisiana and at it's current rate of speed, will do so in the region before sun-up tomorrow. It will be near New Orleans sometime several hours on either side of noon (CT) tomorrow, moving inland and accelerating through the evening. Impacts will be felt all the way to Pensacola in the form of high winds, surge, and heavy rainfall.