Keeping an eye on the tropics & Invest 97L

Even though we currently have tropical storm Harvey heading into Central America. The main concern for the Caribbean and U.S. is Invest 97L.

Invest 97l is just a designation the Navy and hurricane center use to track disturbed areas of weather that could potentially develop into a storm or hurricane. This designation is important because the tropical models start running on these areas. This particular area has been showing up in the global model long before it got a designation.

Here are the latest “spaghetti” plots on Invest 97.


The intensity forecast shows a slow but steady intensification process over the next 5 days.


Yet there are many hurdles for this system to overcome before becoming a major threat. The first of which is the dry Sahara air layer(SAL) that can sap moisture out of these storms.


The second is some shear to the north and west of the system. Though this along with the SAL will be less of a hindrance once it gets into the Caribbean. Then of course if it tracks right over the larger islands of the Caribbean, Hispaniola and Cuba those too could keep it from intensifying rapidly. You can see the main steering currents below which is the huge subtropical ridge over the central Atlantic.

                    Wind Shear                                                Steering Flow


It is interesting to see our RPM model and the high resolution look at surface winds. Based on our model the storm track looks to stay south of those islands. The one big caveat in all of this is there is next to zero upper air or surface data going into these models from the central Atlantic. We will know a whole bunch more when the recon plane gets out in this system Saturday.