Strong Tropical Wave Emerging off Africa (INVEST 99L is up)

[RL3AO]

Also interesting to note that the GFS keeps it mostly a Cat.1 2 through the 1st 10 days. Signs that conditions are not exactly favorable. Typically we would see the GFS bombing out.

That was expected from the old GFS which loved to bombout every other wave that left Africa it seemed. This new GFS may very well be conservative as we may have seen.

Actually if anything the new GFS tends to be more bullish with TC's.

How did you come to this conclusion? (at least for the Atlantic)

[wxmann_91]

Umm, that ridge seems rather strong for a TS to penetrate through that and on top of that there seems to be no trough dipping down far enough to cause a weakness...

Yeah it sure does, but as I said on the previous page the GFS (at the least the old one) is notorious for breaking down ridges or sending storms straight into them. I guess we will see if this is the case again here in coming days.

The reason why the GFS shows recurvature is it parks an ULL to the east of Florida and that precludes the ridge from building back west. Note that models have little skill in predicting ULL evolution.

[wxmann_91]

That was expected from the old GFS which loved to bombout every other wave that left Africa it seemed. This new GFS may very well be conservative as we may have seen.

Actually if anything the new GFS tends to be more bullish with TC's.

How did you come to this conclusion? (at least for the Atlantic)

In two weeks it's shown a fantasy Jova, a Typhoon Tip strength Noru, and a two-categories overblown Hilary. Hasn't been stellar with Irwin or Greg in the EPAC either. I don't know if these problems will translate into the Atlantic basin but there's pretty strong evidence it goes crazy with tropical cyclones.

[Siker]

~13/20 GEFS members have a TC from this by the Lesser Antilles with a pretty huge spread of tracks.

[cycloneye]

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 PM EDT Wed Aug 2 2017

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

Showers and thunderstorms near the coast of west Africa are
associated with a tropical wave. Environmental conditions are
forecast to be conducive for some development during the next
several days as the system moves to the west or west-northwest at 10
to 15 mph over the tropical Atlantic Ocean.
* Formation chance through 48 hours...low...10 percent.
* Formation chance through 5 days...low...30 percent.

$$
Forecaster Blake

[Nimbus]

30% and it hasn't even left Africa yet!
Guess this is the one to watch.

[gatorcane]

Looks vigorous:

[Hurricaneman]

I'm thinking invest later tonight or tomorrow morning

[AutoPenalti]

30% and it hasn't even left Africa yet!
Guess this is the one to watch.

Well that's the five day track.

[Emmett_Brown]

Just eye balling the satellite photo, it seems to have a fairly large envelope, so not sure this will be a compact storm like the others so far. I guess it depends on how much dry air it has to contend with (tends to shrink storms)

[floridasun78]

i see wave front of it having dry air issue so need moisture stay front of it pull sal that not big as before alway

[cycloneye]

@webberweather
Convection induced by the Guinea highlands & a CCKW likely to blame for recent increase in NWP support for TCG of an AEW over West Africa

 https://twitter.com/webberweather/status/892906564725727232

[MetroMike]

We are on "Poof Watch" for this one.

[tarheelprogrammer]

@webberweather
Convection induced by the Guinea highlands & a CCKW likely to blame for recent increase in NWP support for TCG of an AEW over West Africa

 https://twitter.com/webberweather/status/892906564725727232

What does he mean? That it is a false alarm?

[abajan]

We are on "Poof Watch" for this one.

Not this time. This one will develop.

[cycloneye]

@webberweather
Convection induced by the Guinea highlands & a CCKW likely to blame for recent increase in NWP support for TCG of an AEW over West Africa

 https://twitter.com/webberweather/status/892906564725727232

What does he mean? That it is a false alarm?

Is the contrary.

[RL3AO]

What does he mean? That it is a false alarm?

Probably not. This is a case of a AEW being amplified by convection over western Africa (Guinea Highlands) vs eastern Africa (Ethiopian Mtns) leading to the models picking up on it later.

[Hurricaneman]

The 18zGFS has this hitting Long Island and , Rhode Island, and eastern Massachusetts at 324 which means usually they're safe but who knows

[cycloneye]

Looking very good as it emerges the coast.

[TropicalAnalystwx13]

@webberweather
Convection induced by the Guinea highlands & a CCKW likely to blame for recent increase in NWP support for TCG of an AEW over West Africa

 https://twitter.com/webberweather/status/892906564725727232

What does he mean? That it is a false alarm?

De-abbreviating it may make more sense.

CCKW = Convectively-coupled kelvin wave. Associated with rising air that travels west to east. Like the MJO but on a shorter scale.
NWP = Numerical Weather Prediction (models)
TCG = Tropical cyclogenesis (TC formation)
AEW = African easterly wave (tropical wave)
Guinea highlands factor in because the mountains help waves consolidate vorticity.