The NOAA G-IV jet flew what is called a synoptic mission yesterday in the environment well out ahead of Isaac to sample the atmosphere. The data collected was input in to the various global computer models to help narrow down the forecast track. In some ways, it seems to have helped, in others, not so much. And as if to add to the challenges already present, Isaac veers off the forecast track some overnight- steering more west than predicted.
All in all, the general idea of an eventual Gulf Coast landfall is still the solution of the major global computer models. Exactly where and when remains to be seen as well as to what extent the Florida peninsula will be impacted.
Right now, Isaac is still rather poorly organized. For what ever reason, its central core just can’t get aligned vertically. Instead, it is meandering around a larger envelope of low pressure. Sure there are numerous areas of deep convection seen in satellite imagery, but Isaac is still struggling. It is noteworthy though that the central pressure is now down to 1000 mb, so in that regard, it has strengthened a little.
The very latest from the NHC shows a track over Haiti, eastern Cuba and then the western most Florida Keys over the next three days or so. After that time, Isaac has a clear shot over the open Gulf to approach the coast, seemingly along the Panhandle. We know the five day position has a significant error factor and that the position will certainly change over the weekend and in to early next week. One key element of tonight’s computer models is the ECMWF which has stopped its westward forecast showing a landfall in Louisiana to a forecast coming much more in line with the U.S. generated GFS model. In fact, the two models are in remarkable good agreement – probably a result of the upper air data that was added recently from the G-IV mission. I know a lot of people along the central Gulf Coast from Mississippi west were getting quite concerned as each forecast seemed to increase the threat from Isaac. I do not know if we are seeing a honing in of the true landfall location now or not, there is still too much that can change over the next 120 hours or more. People anywhere from the peninsula of Florida to New Orleans need to keep tabs on Isaac and be ready to take action if needed.
As for intensity? Who knows? This part of Isaac’s forecast over the last few days has been the toughest challenge for the NHC. As I mentioned, without a well defined inner core, Isaac stands little chance to intensify before moving over the rugged terrain that lies ahead. Nevertheless, it will dump a lot of rain on that land and flooding will be a major concern. Isaac is also a large tropical storm with a huge wind field. This will mean a longer period of time that tropical storm conditions will persist for any land areas that Isaac impacts. Remember, it’s not just around the center that the winds are strong. The outer bands contain heavy rain and strong winds too and these will affect Florida sometime over the weekend. I cannot say it enough times: tropical cyclones are not just wind machines, they have rain, storm surge and the possibility of tornadoes and downburst winds. Not to mention the rough surf that accompanies any tropical system, no matter how weak or strong. A storm of this size commands respect, especially if it ever suddenly begins to strengthen.
So if you live in Florida, anywhere in Florida, you should be watching Isaac closely this weekend. The Keys will be the first to feel the effects as will southeast Florida. A lot of people live down there in Dade and Broward counties. The rain bands will wreak havoc on traffic so be careful out there. Once the weather goes down hill, just stay off the roads and monitor conditions from home. Hopefully you have the needed supplies in case the power is lost and as long as Isaac does not make landfall in southeast Florida, the effects will be in and out and things can go back to normal early next week. Of course, we will then have to focus on a potential landfall along the Panhandle. With so many days still left until that would happen, we are still in a wait and see situation for now but people in that region should be ready to act if Isaac does in fact come your way.
The rest of the tropics are a non-issue right now. TS Joyce all but completely sheared out yesterday and may never recover. Then, invest area 97L in the far eastern Atlantic is certainly worth watching but not a concern at this time.
I’ll have today’s video blog posted to the HurricaneTrack app early this afternoon after the 11am NHC advisory package comes out. I’ll also post an update here at that time as well and will begin talking about our landfall mission plans for next week.