Soon To Be Isaac -Update # 4

First off we are going to start off by showing what the National Hurricane Center is thinking  as far as development is concerned.. And this is something that we agree completely with. You can see on the water vapor image above that convection is firing and we are starting to see some banding occurring.  
At the time of this writing the shear images thru CIMSS were not updating for whatever reason so we will not be looking at the shear. 
So we are going to look at current conditions around soon to be Isaac . 

First thing that we want to look at is the vorticity and as you can see from 24 hours prior that the vorticity has tightened up and is not stretched out and elongated as it was . This is a good thing to see with a developing cyclone.

 Despite the vorticity getting better organized we can see that there is still alot of dry air to the north of this system, and even around the system ..as well as off to the west of the system. This is one thing that will help to cause this development to be slower over all. 

 Now the next area to look at is the convergence (above) and the divergence below and at the present time the convergence across the system is decent but the area of best divergence is off to the southwest of the system (image below) .. 

Now with all that mentioned , (shear images not available) we feel that the the environment is better tonight then it was just 24 hours ago ..besides the dry air. So we feel that this will probably be an Tropical Cyclone by the NHC 5 AM update..

Now what about the tracking of this system.. Well to determine this we have to look at the steering currents at which this system would be subjected to follow.
We mentioned in the previous update that because of the currents that this would take a more west to south west track and that continues to be the case and this would be because of the flow around the mid tropical and subtropical ridging to its north.

Now this should continue to move at a rapid pace towards the west with a hint of south based on those steering currents. So the question really becomes what is going to happen with soon to be isaac? 
There is a lot of talk and speculation about the system coming up the east coast and this is all being based on the Global Forecasting System or GFS model. However..this is based off the GFS creating a weakness in the mid level ridging. However..this can be a bias of the model and that is why we are not talking the track on the operational model as is.
At the present time we are not forecasting this to come up the eastern seaboard. We think it makes more synoptic sense with the strong ridging forecasted to stay north of the system to keep this on a west track with a touch south of the due west.. Lets look at the guidance that is being shown tonight ..

 First image above is the 00z GFS ensemble members and while some of them do show this taking a track towards the eastern coast of Florida..majority of them are taking this towards the GOM. 

 The next image above is the ECM which shows the system taking a westwards track and moving into the eastern GOM ..near Florida. 

 The image above is the 00z UKMET , one can see that this too would be appearing to take a track that would end up on the western side of FL.. Matter of fact you can see this by looking at the hour 144 on the UKMET and it is going south of Florida..

Still yet one more piece of guidance to look at is the GGEM and this is very similar to the GFS model. It takes it on the eastern side of the state of Florida. 

 This last image is the 00z Dynamical model guidance and as you can see the majority of the models take this either towards florida or to the west of Florida into the Eastern Gulf..

So basically we have the GGEM/GFS camp showing what could be an east coast threat and the ECM/UKMET along with majority of the above models , in addition to the majority of the GFS ensembles taking this more west.
Now the question becomes land interaction such as Hispanolia and Cuba. The weaker the system is going across the islands the less damage it will do. However with a further south relocation around 15 N.. this could mean that this will slide under those islands. 

In summary we are not calling at this present time for a Hurricane to move up the east coast . As stated the only reason the GFS does that is because it breaks down the ridge to quickly! With the ridging in place we expect a approach towards FL or passing just south of Florida before it turns more into the Eastern GOM..