Tropical Storm Fiona Weakening; Watching Invest 99L

It has been a few days now since Tropical Storm Fiona formed well out in the Atlantic Ocean. However, Fiona is now weakening. It is weakening mainly due to the fact that it is heading into an area of very dry air.

Water Vapor Loop

Tropical Atlantic Water Vapor Loop

There is also a decent amount of wind shear ahead of Fiona as well:

Wind Shear map as of Friday afternoon

Below is the latest from the National Hurricane Center in regards to the track and intensity of Tropical Storm Fiona. The NHC also expects Fiona to weaken to a Tropical Depression by Sunday:

NHC cone track for Tropical Storm Fiona as of 11:00 AM advisory on Friday, August 19th

—————————————————–INVEST 99L—————————————————-

That’s right, folks! Right behind Tropical Storm Fiona is another tropical wave that we are watching, which is now Invest 99L. The latest from the National Hurricane Center is that it has a 50% chance of developing in the next five days (as of Friday). The orange area below is the area to watch for development:

INVEST 99L HAS A 50% CHANCE OF DEVELOPING IN THE NEXT 5 DAYS

This is something to watch for POTENTIAL impact. However, there are a few things that may impact the development of Invest 99L. For example, wind shear. Although there is some decreasing wind shear around the current area of Invest 99L, there is also an area of INCREASING wind shear ahead of it:

You could see the decreasing wind shear (blue dots) to the Southeast of Tropical Storm Fiona. This is the current area where Invest 99L is located. Ahead of it, you see increasing wind shear (white circles). This may have a say on whether or not Invest 99L develops into a tropical system.

In regards to dry air, there is some dry air out ahead of it, but not a whole lot, so it may be able to overcome any dry air, if it makes it.

Lastly, here is a look at the latest spaghetti plot models and intensity guidance for Invest 99L (PLEASE NOTE THAT EVERYTHING BELOW IS NOT A FORECAST! ALSO REMEMBER THAT THIS IS GUIDANCE, NOT GOSPEL. THINGS WILL CHANGE OVER THE COMING DAYS!)

GLOBAL & HURRICANE MODEL GUIDANCE

GFS ENSEMBLES (GEFS) MODEL GUIDANCE

CMC MODEL GUIDANCE

INVEST 99L INTENSITY GUIDANCE

Stay tuned for the latest information and updates on the tropical Atlantic.

Have any questions? You can always tweet me @jonathonrocco and I will answer you as soon as I can!

Have a great weekend!

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