Tropical Storm Isaac -What is Going On?

As we mentioned last night there is several different outlets online that are talking about Isaac and the path that Isaac will take. The forecasts range from off the east coast of Florida and up the eastern seaboard to going across central florida riding inland and then up the coast inland..to going into the Gulf of Mexico.. And the forecasts are becoming a little bit interesting but we really do not have any "true consensus " yet..

The very first thing that we notice is that Isaac is better organized tonight then say 24 hours ago. Its not being effected as much by the dry air that was around the system and hence why it is now up to 45 MPH sustained winds.. 

I think it is very important to realize that this system is subjected to the steering currents that are in place and when you look at them you see a huge subtropical ridge to the north of Isaac. Now this is important as this is the KEY DIFFERENCE between the ECM and say the GFS...

Pro Met David Tolleris from Wxrisk.com did a good job of pointing this out ..

The difference is quite simple the GFS has a piece of energy over Kansas, where as the ECM the trough is really north of Montana and simply would not have any influence on Isaac. The Kansas shortwave causes the ridge to break down sooner which then allows Isaac to go up the eastern side of Florida (at first) before then travelling across the central part of the state then moving NNE along the interior until it is a weak remnant low over SNJ (1009 mbs) but that is only after stalling it south of De for about 12 hours.
The GFS does have support from other guidance . It has the GGEM on its side.. and what really raises a red flag to us is it also has the NOGAPS on its side.

Top image is the GFS, middle the GGEM and the bottom is the NOGAPS. Now we know in winter time the NOGAPS can be used as a useful model. However remember one of its main biases is that it is too progressive..more progressive then the GFS /GGEM which also can be to progressive. So you can see that these three models are in the same camp as one another.  

Now lets talk a bit about those three models.. 
1. The GFS has been pretty eratic with its track. From the west side of Florida to the east side of florida to even runs showing a hurricane very near NJ. The GFS manages to keep the inner core intact as it crosses across Hispanola and Cuba. 
2. The GGEM has been showing a fishing scenario which has now come well west.. So we see no consistency in that model.
3. The NOGAPS.. the most progressive model of the three above and notably not well with tracking tropical cyclones...

Now..remember those steering currents and remember the ridge? Well, here is one more difference the ECM while it mainly goes south  of Cuba and Hispanola it does get close enough that the centers (mid and lower) decouple.. in other words the Islands disrupt the inner core and with stronger ridging from west to east it shows a more western track..

Lets look at the ECM now..

As you can see the ECM takes a track that is south of the islands and really blows this up into the GOM. This would be a MAJOR hurricane as it approached the Northern Gulf coast. Now this should not really be a surprise considering all its ensemble means save 2 were showing a similar depiction in track. That is fairly significant itself in that they both agree..

Now lets briefly look at the rest of the current conditions ..Shear is decent with only 5-10 knots ..Divergence and convergence across the system are both decent..However the shear tendency map does show an increase in shear to its west..

Present movement is due west at 18 MPH. Again when one looks at that steering currents it clearly explains why the system is heading due west..

So we issued this track earlier in the day and we are sticking to it at the present time..

We see no compelling reason to deviate from this thinking. GFS is to progressive and to quick in breaking down the ridge. In order for something like the GFS/GGEM or even NOGAPS to occur this would have to start gaining latitude and latitude quickly. And of course there would have to be a weakness in the ridge which is not expected for at least the next 72 hrs which would already start to take this to the south of the Islands...  Latest recon suggests that the center is already further south then what it was earlier today. This all lends credence to the ECM. 

We will update this once again in 24 hours .. Follow along on Facebook just do not forget to click like on the page..  https://www.facebook.com/B.W.B.T.R