While Isaac continues to Weaken -Attention Turns East!

Seems like there is never a dull moment when it comes to forecasting the weather and in particular forecasting the tropics. While LA and portions of the south central region continue to be battered by Tropical Storm Isaac there is another Tropical wave east of the Lesser Antilles and this is up to a 90 % chance of Development...

Now what we want to do here is show some initialization of the European Computer Model and its features that are important players at this point and time at least in the upper levels of the atmosphere.

The map is pretty self explanatory. It is the 500 mb level and you can see where 98 L is located as well as the ridging that is in place as well as a small weakness in that ridge. Majority of your guidance tonight is showing it finding that weakness...

If these tracks become realized then this would NOT pose a threat to the USA. This would stay harmlessly out at sea. However.. as Tropical Forecasting has showed models generally do not have a grasp on the scenario until a center of circulation is involved and at this point and time we still do NOT have that..
We bring the ridging up initialized above because we believe it plays an important role in the short to medium term. Lets look at the steering currents as of 6 Z..

This shows you the ridging that we were talking about off the ECM and this also shows you the weakness that we referenced. Essentially what this says is that in the near term this should continue mainly on a western track..

We have some things working against fast development and that would be the dry air that is in place around the invest. 

Still yet another thing we see is that the vorticity of this system is rather stretched out and elongated.
One other thing that we have also noticed has to do with the shear and that is that it is on the increase to the west of the system..

Things in favor of development..
1. Convergence and divergence while in reality it does look off to the west a bit ..the wave is still in a decent area of each..

2. Present wind shear and the presence of an anti cyclone over top of the system..

So as you can see there are some things that would favor development and some things that we seeing that would hinder development

Now what makes this interesting is there are only 3 models that go out to 240 hrs and that would be the GGEM,GFS and ECM.. GFS and GGEM both keep future Leslie out to sea. However the European suggests that 98 L could come towards the Cape Cod region.

While this model is all alone right now in what it is showing we would be in the wrong to quickly dismiss the model just because it is alone at the present time. 

This system should continue to move mainly west with the steering currents  in place. Next update will be in 24 hrs from now ..And we think this should get named a depression within the next 12 hrs,,, Stay tuned for more coverage and out looks via our facebook page!