UPDATED!! Tropical Depression 7 Forms Near Africa. Invest 99L Looking Stronger. More Convection. Invest 90L 100% Chances to be Gaston Yet Gaston Isn't Threatening Islands and SE Coast. Models Show a Possible Threat. Hurricane History Lessons Help us Understand 99L and a Possible Ridge Forming.

5 PM 

Tropical Depression #7 Forms

Cone:

So far TD 7 is forecast to be a Fish swimming out to sea.

Check back in a few days to make sure there's no change of plans.

Closer to home we have Invest 99L

Going to focus on 99L as it's forecast to be a problem.

Easy to say TD7 will be Gaston.

Invest 99L will have to work really hard...

...at rapidly intensifying to get that name.

Time will tell.

Map above from www.hurricanecity.com

Right now the models show a possible SE Coast Landfall for 99L 

That's more important than a distantly named Tropical Depression.

You look at Invest 99L and you think to yourself this must be much to do about nothing. I mean Invest 90L is on it's heels looking like a hurricane and 99L is a messy blob. But that's not right and the models are forecasting a slow, building Tropical Storm that would reach Hurricane intensity in the next week. Why you ask?

1. It gets closer to warmer water with ever mile. Warm water to a developing storm is fuel to keep growing.

2. It is forecast to soon be under the influence of a High aloft. You know as in "go for lift off" as that feature would enhance convection and favor intensification.

3. Oceanic Heat out ahead of it waiting to help fuel this storm and possibly allow it to explode and ventilate it into a contender vs a weak, westbound tropical wave known as Invest 99L. I said "possibly" as we are talking possibilities should a Tropical Storm form from 99L.

4. Climatology is in line with a wave moving in this direction to intensify. Late August going into early September was the time that mariners worried on when traveling in the tropics.

5. So say we have a weak Tropical Storm wandering around the huge high slowing down as it reaches that point where the High exerts less influence.

That's the current last frame on the 7 day NWS loop.

Shows a ridge. 

If that dotted line becomes a storm there's a problem.

6. A ridge is forecast to build to the North of where this system would be at a point where water temperatures are extremely high. It's common for storms to ramp up in the Bahamas East of South Florida and this could happen.

Then it's all a matter of timing and events that have not yet played out but are forecast to create a "push" towards land for what may be Hermine. That does not mean it makes landfall but skirts to the North if a door opens in the ridge. Remember Hurricane David that was forecast to slam into Miami and suddenly lunged North?

7.  The very size of the wave that created Invest 99L makes it a threat as a Hurricane down the road. Why? Because a storm usually keeps it's form from day 1. This had the classic Cape Verde Hurricane look. If it fills up that pocket it had around the dot of convection if had yesterday morning we could have a serious problem.

Invest 99L is not just producing convection it is pumping... has early rudimentary banding on the SW side and ventilating on the NE side and has that look...

8. Too little attention too late could create a bad scenario for people in South Florida and the Bahamas though to be honest my concern is South Florida today. If it finds a way North like many do then it's Carolina's problem.

Note it traced the High.

Intensified in the Bahamas just ESE of Miami.

Made the turn and headed towards the Carolinas.

I'm not saying Hermine could be another Floyd. I'm saying that Hermine should she form from Invest 99L would be Hermine. Each storm has it's own unique problems and qualities. But there are similarities of a strong High or a ridge building in. Note I put this image up to show you that Floyd, big memorable hurricane, formed at 50 West. Had Floyd formed out near the Cape Verde Islands he'd probably have been a Fish storm.

9. Invest 99L has more lives than a cat it seems. Speaking of cats in the days when we were watching Katrina form not far off shore from Miami I kept calling it Kat playfully. At that time we had no idea Kat had bigger plans ahead than just Miami... way before it made landfall and broke the dikes in Nola we were worrying on Katrina. Why? There was a ridge building in and there was an intensifying tropical system suddenly with a name.

Track is obvious example of a ridge problem.

Good news is as I stated above in 9 different reasons.

Invest 99L is likely to form further out.

Where the ridge will be I can't say yet.

But we are getting closer to knowing.

The Bottom Line is every storm is different. So many factors in play that each storm reacts just a drop differently. Example compare and contrast Betsy and Katrina. If you say they both hit South Florida and Louisiana you'd be right. But the details are different, tracks different. Yes, a ridge built in and that is why we fear the ridge when we have tropical systems on the maps.

Okay not sooo different but you get the idea.

Formation at a different spot.

Betsy went thru the Islands.

Andrew formed further out, up over the Islands

You see how much easier it is for a Hurricane to miss Hispaniola?

Sorry that was not reassuring.

Truth is we are still watching an Invest intensify.

Invest 99L pushing into the dark, dry air.

Start of a loop:

End of the loop:

Putting on a show isn't it?

Remember the dot image from yesterday morning?

Current NRL image of Invest 99L

Impressive.

Convection increasing. 

That was the first step in this process.

There may be some shear down the road.

It has a long way to go.

Right now rather than obsess on models that change hourly.

I wanted to give a good look at Invest 99L

Explain why it most likely will be TS Hermine.

Could he Hurricane Hermine.

Note the tracks.

Note the water temperatures.

Note the steering current.

Good to maintain a sense of humor when the tropics heat up.

And we thought all we had to worry on in Miami was Zika..

2 weeks from now we will know what happened to 99L

The models are changing so often it's hard to trust them.

They are beginning to come together...ish.

I'm ignoring the stronger Invest 90L forecast to be a fish.

Boy hope they are right with that one.

Some models make it a monster hurricane.

Yes I said monster vs major as I mean size wise.

How would that affect a Tropical Storm Hermine?

A lot of questions.

How do the remnants of Fiona play in here?

Stay tuned.

I'll be back later when there is something definitive to say.

Besos BobbiStorm

@bobbistorm on Twitter

Ps. As a Hurricane Historian I close my eyes...

...and I see hurricanes forming.

So many different tracks looking back.

So many different endings to the story.