Good Morning. Like I said yesterday I plan on doing one discussion a morning unless something comes up, in which case I’ll do supplemental discussions such as I did yesterday afternoon. The graphic above depicts the model outputs on the track of Tropical Storm Bonnie. These are from the 06Z suite this morning. The models have kept a fairly uniform track over the past day with a landfall in Southeastern Louisiana. They have sped up the system, however, which has brought the landfall time up about twelve hours to the pre-dawn hours on Sunday. Tonight the system has been racing moving at speeds over 20 MPH. That’s pretty high for a tropical system and when recon entered Bonnie earlier this morning the question of whether or not this still was a tropical system (of any kind) become clear.
The first thing to notice about Bonnie this morning is the very small area convection is covering, although it is fairly strong for a system this weak. The problem is that the Low Level Circulation has become detached from that convection, and thus has weakened overnight. When the Hurricane Hunters entered the system at 2 AM CDT they had difficulty finding any west winds, which would indicate a low level circulation, and thus a tropical system. Without a low level circulation this is nothing more then an open wave or a mid-level circulation that could be associated with common weather systems. Recon did eventually find west winds, but they were very weak. At this point its unclear whether or not Bonnie will survive the morning.
If you notice the 5 AM position of Bonnie you will see that she is beginning to encounter stronger wind shear again. Because this system is so weak it does not take a lot of wind shear to negatively affect the circulation and that is exactly what has been observed this morning. At this point winds at the surface are still reaching 40 MPH, but this is mainly associated with the convection not necessarily the low level circulation of the storm. It’s not clear what exactly will happen with Bonnie today. Its possible that the circulation could ramp back up fast and in a few hours look better then it has before, or it could continue to deteriorate and we could end up with an open wave by noontime. The way the system looks now, It is not looking good for the future of Bonnie. Besides that there really isn’t much to talk about. Its clear that Bonnie will not have much time to organize in the gulf and based on her present structure and forecasted conditions in the gulf its not likely she will strengthen significantly. The track forecast has some confidence to it and it looks like landfall will be somewhere in Eastern LA or Western MS.
I will have another discussion posted later this afternoon with the hope Bonnie makes up her mind on what she is going to do, whether she just falls apart or gains some structure in her inner core. Either way the big story will be the heavy rainfall and the unfortunate impacts from the oil spill. Stay tuned to the site, or follow us on our social media accounts for the latest information.