SOUTH MISSISSIPPI (WLOX) - Monday evening, Tropical Storm Erika formed in the Atlantic, well east of the Lesser Antilles. The 4 p.m. update from the National Hurricane Center said the storm is moving west at 20 mph. The storm has a sustained wind speed of 40 mph and a pressure of 1004 mb, which means it has weakened slightly.
The storm is expected to intensify slowly over the next five days and approach the east coast of Florida as a category one hurricane. While this may sound menacing, the storm will be approaching an area of strong shear that will be moving through the Gulf of Mexico at that time and across Florida.
Strong shear is what made Danny collapse so quickly. If Tropical Storm Erika does make it to the east side of Florida, it will more than likely encounter that strong shear.
So, what is shear? Shear is a differential in wind speeds. We look at this differential in wind speed vertically for tropical forecasting.
Tropical systems need to be stacked vertically so they can spin, much like how a top needs to be standing up straight to spin. When these systems encounter areas of strong shear, it causes them to tear apart. If you think about it like a top, lay it over, and you can't spin a top on it's side. That basically means storms fall apart quickly in areas of strong shear.
It is still five days out before Erika approaches Florida with it's projected path, but things can change in five days and more weather models than not have this storm turning to the north.
Stay with the WLOX 24/7 Weather Team as we keep you updated on Erika.