ATL: INVEST 94L - Discussion

[wxman57]

NHC has identified the wave near 12N/21W as Invest 94L. I think it has a tough road ahead of it, as the most favorable environment appears to be today and tomorrow. Beyond then, a combination of dry, sinking air and a wall of increasing shear across the Caribbean awaits.

My opinion is that the NHC's probabilities are reversed. I'd say maybe a 20-30% chance it could become a TD today/tomorrow, followed by little or no chance through 3-5 days. There is already evidence of an LLC with convection overhead, but that's not unusual for a strong disturbance that just moved offshore. Way beyond 5 days it may have a shot at development if it can move north of the Caribbean.


TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
800 AM EDT WED JUL 29 2015

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

A tropical wave accompanied by a weak low pressure system is
producing an area of showers and thunderstorms a couple of hundred
miles southeast of the Cape Verde Islands. Environmental
conditions are expected to be at least marginally conducive for
some slow development through the weekend while the disturbance
moves westward at about 15 mph.
* Formation chance through 48 hours...low...near 0 percent
* Formation chance through 5 days...low...20 percent

[wxman57]

Looks like the Space Shuttle's RapidSCAT instrument caught the disturbance overnight. There's definitely an LLC, though it's not well-organized. It's best shot at development is over the next 24 hours before it encounters increasingly hostile conditions farther west.

[blp]

Looks like the Space Shuttle's RapidSCAT instrument caught the disturbance overnight. There's definitely an LLC, though it's not well-organized. It's best shot at development is over the next 24 hours before it encounters increasingly hostile conditions farther west.

[]http://manati.star.nesdis.noaa.gov/rscat_images/cur25/zooms/WMBds32.png[/img]

Thanks for feedback. I agree it will have a limited window. Shear forecast looks good the next few days.

[gatorcane]

satellite loop:
http://rammb.cira.colostate.edu/ramsdis ... display=12

[Gustywind]

Any models plots my friends? Tkanks.

[SouthDadeFish]

GFS certainly suggests there will be a LOT of dry air in the path of this invest.

Here's the current mid-level relative humidity:



And here is the 120-hour forecast:



The disturbance essentially disappears as the dry air wraps around from the north. Keep in mind this is just one run, but conditions don't appear too favorable...

[tailgater]

I noticed it last might on the water loop and thought that I was surprised it was getting mentioned on this form, we don't miss anything.
Although I think it looked better last night, out flow wise.

http://www.ssd.noaa.gov/goes/east/tatl/h5-loop-wv.html

[tatertawt24]

NHC has identified the wave near 12N/21W as Invest 94L. I think it has a tough road ahead of it, as the most favorable environment appears to be today and tomorrow. Beyond then, a combination of dry, sinking air and a wall of increasing shear across the Caribbean awaits.

Also known as the Atlantic basin for the past three years!

[wxman57]

The environment around 94L just gets more hostile the farther west it tracks. That's why best development chances are not in the 3-5 day time frame - they're today. And since the NHC is giving no indication that they're about to classify the disturbance as a depression, it will likely be allowed to dissipate.

It won't look any better than it does now over the next 5 days:

[cycloneye]

57,any chance this may at least aliviate our drought or it goes north of the Antilles without bringing the rain?

[ninel conde]

Carl Parker was saying the SAL is the most robust its been for at least the last 10 years. doubtful any moisture can make it to the islands in that environment.

[gatorcane]

looked at the floater out of RAMMB, convection is blowing up over the LLC:

[floridasun78]

so going be short live tropical system if do form to be td??

[TheStormExpert]

so going be short live tropical system if do form to be td??

Most likely.

Just MAYBE it could find a quick window to become a TS and not end up being forgotten like all the other Tropical Depressions.

[cycloneye]

Umm,not bad.

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
200 PM EDT WED JUL 29 2015

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

A tropical wave accompanied by a broad low pressure system continues
to produce shower and thunderstorm activity a couple of hundred
miles south-southeast of the Cape Verde Islands. Environmental
conditions are expected to be somewhat conducive for slow
development of this disturbance through the weekend while it moves
westward at about 15 mph.
* Formation chance through 48 hours...low...10 percent
* Formation chance through 5 days...low...30 percent

$$
Forecaster Stewart

[SouthDadeFish]

I don't mean to bash the NHC but I truly do not understand the logic in these percentages for development. I'm with wxman57. Only 10% chance in the next 48 hours??? But yet 30% once it moves into the large plume of dry air? Huh?

[cycloneye]

Unless they know about a small window that may open down the road?

[floridasun78]

nhc know some thing wx dont their pro

[SouthDadeFish]

Regardless, not a bad looking disturbance at the moment:



And cycloneye, perhaps. The only way I see this thing surviving is if it is somehow able to wrap up really quickly over the next 24 hours such that it may be strong enough to battle the dry air. Huge IF.

[Yellow Evan]

Dry air will be an issue, but wind shear won't be too too bad.

SHIPS shows steady deepening throughout the period.