ATL: INVEST 90L - Discussion

[curtadams]

It's collapsing because once offshore, it no longer has the tremendous surface heat of the Sahel to drive updrafts. The ocean off the West African coast is relatively mild because of currents from the north. This happens to almost every wave that moves off the coast there - huge convection ashore which sputters and weakens after it moves offshore.

[Sanibel]

This has a large circulation. It should develop if it refires.

[cycloneye]

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
200 PM EDT THU SEP 4 2014

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

A tropical wave, accompanied by a broad low pressure system, is
located a couple of hundred miles east-southeast of the Cape Verde
Islands. Development, if any, of this disturbance is expected
to be slow to occur over the next several days while it moves
westward at about 15 mph.
* Formation chance through 48 hours...low...10 percent.
* Formation chance through 5 days...medium...30 percent.

$$
Forecaster Pasch

[Alyono]

not believing the 12Z guidance I take it

[tolakram]

Down to 30.

Latest

[gatorcane]

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
200 PM EDT THU SEP 4 2014

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

A tropical wave, accompanied by a broad low pressure system, is
located a couple of hundred miles east-southeast of the Cape Verde
Islands. Development, if any, of this disturbance is expected
to be slow to occur over the next several days while it moves
westward at about 15 mph.
* Formation chance through 48 hours...low...10 percent.
* Formation chance through 5 days...medium...30 percent.

$$
Forecaster Pasch

[gatorcane]

Down to 30.

Latest

http://imageshack.com/a/img661/6702/2c97O4.jpg

That's interesting especially since the 12Z guidance trended a little more bullish...

[CrazyC83]

I don't see anything developing before reaching the Caribbean at least. The deep tropics are just incredibly hostile right now. This might just ultimately be more EPAC juice.

[Alyono]

convection refired

Not sure what Pasch seen to lower than probabilities

[gatorcane]

convection refired

Not sure what Pasch seen to lower than probabilities

You just beat me to this as I was going to post the same thing

Here is a saved looped so members can see this convection firing - this is a very good sign:

[somethingfunny]

convection refired

Not sure what Pasch seen to lower than probabilities

Would you say 90L is more likely to develop within 5 days, or develop in 6 or more?

[Alyono]

I'm thinking maybe an even money shot during the next week, but it shouldn't become that intense. Maybe a TD/weak TS if it develops

[cycloneye]

18z Best Track.

AL, 90, 2014090418, , BEST, 0, 132N, 201W, 20, 1009, LO

[TheStormExpert]

convection refired

Not sure what Pasch seen to lower than probabilities

Probably basing it off of the trends of every TW so far this season struggling to develop until it approaches the Lesser Antilies/Caribbean Islands.

[AEWspotter]

For what it's worth, SHIPS is forecasting shear below 20 kts (and speed-adjusted shear < 10 kts) for the forecaseeable future. I like the chances for development. But, the system might struggle with some dry air, which is why none of the statistical models develop 90L into a hurricane. The question is whether or not this system will be able to sustain itself as it crosses the Atlantic.

SHIPS output: http://www.ral.ucar.edu/hurricanes/real ... _ships.txt

The GFS is bullish on this system deepening near 50W. Systems always seem to get their act together in this "go zone".

[SFLcane]

I'm thinking maybe an even money shot during the next week, but it shouldn't become that intense. Maybe a TD/weak TS if it develops

What you make of overall steering? gfs ensembles all show some type of westward bend towards Bahamas.

[SeGaBob]

I personally would of went 20/50% on this one but that's just me.

[abajan]

It's collapsing because once offshore, it no longer has the tremendous surface heat of the Sahel to drive updrafts. The ocean off the West African coast is relatively mild because of currents from the north. This happens to almost every wave that moves off the coast there - huge convection ashore which sputters and weakens after it moves offshore.

That's true. I've seen it happen numerous times.

[NDG]

For what it's worth, SHIPS is forecasting shear below 20 kts (and speed-adjusted shear < 10 kts) for the forecaseeable future. I like the chances for development. But, the system might struggle with some dry air, which is why none of the statistical models develop 90L into a hurricane. The question is whether or not this system will be able to sustain itself as it crosses the Atlantic.

SHIPS output: http://www.ral.ucar.edu/hurricanes/real ... _ships.txt

The GFS is bullish on this system deepening near 50W. Systems always seem to get their act together in this "go zone".

My question is how much can we by with the SHIPS shear and 700-500 mb RH forecast when the BAMM model track, which its intensity forecast is currently run on, shows it gaining much more latitude than what the global models are showing.

[gatorcane]

Here is the most updated SAT image I could find as the NHC floaters are a couple of hours behind. The convection continues to expand near the center of the broad low: