Tropical Wave off African Coast (Is Invest 95L)

[gatorcane]

I am little surprised the NHC has not lemoned this invest yet as there is some partial model support for something to form within 5 days. The GFS, FIM, and NAVY models are showing development.

Looks like the models might be struggling a little with the interaction of this pouch and pouch 17L off to the SW of the Cape Verde islands. It's still quite possible both pouches will merge and something will form out of this. I certainly wouldn't say the development chances are 0, probably around 20% within 5 days.

Also, it looks like there is a weakness to the north due to a mid-latitude trough weakening the Azores High which is why these pouches are forecasted to move very slowly west for the next several days, but eventually the High builds back in and shunts whatever forms out of this pretty quickly to the west it looks like.

Saved image showing Pouch 17L to the left and Pouch 18L to the right:


The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products

[cycloneye]

Here is todays analysis by the pouch folks of Pouch 018L. Interesting first paragraph.

P18L
13N, 10W
700 hPa

In yesterday’s attempt to track the feature that emerges from Africa in several days, I assigned very uncertain positions to a weak feature starting far to the east near 10E. In today’s models, the story is different, with a slightly better trackable feature starting around 10W that then comes slowly off of Africa and interacts with P17L, as well as another distinct pouch that starts even farther to the east around 20E (not tracked). The result is an apparent “jump” to the west of P18L, with the main culprit being (1) weak depiction of early P18L in yesterday’s models, (2) poor analysis by me, or (3) a combination of both.

ECMWF: Starts just to the east of the African coast. As it crosses the coast on the first day, P18L comes close to the northeastern side of the larger P17L and is absorbed by P17L.

GFS: OW max develops into a pouch near the African coast and becomes stronger than P17L to the west.

UKMET: Absorbs P17L and becomes a large pouch tracking to the west with low but enough vorticity to hint at a long-lasting pouch.

NAVGEM: Small weak pouch emerges from Africa and temporarily becomes stronger than P17L. P17L and P18L remain distinct from each other as they stall over the eastern Atlantic. By 120 hours, P18L weakens while P17L to the west exhibits reintensification.

http://www.met.nps.edu/~mtmontgo/storms2014/P18L.html

[cycloneye]

This pouch has been introduced as a Tropical Wave on the 12z surface analysis.

[Alyono]

THIS is the TW, not that convection to the east

[gatorcane]

It looks to me like the broad circulation center is just off the coast and moving slowly WNW. Convection looks pretty healthy near the "center" of this broad circulation...question is, will it continue to build convection once it moves further offshore in the next day or so?

[Alyono]

development highly unlikely through at least the next 5 days

No moisture, no instability

[Hurricane Andrew]

^It already seems to be developing banding...

(SAT loop from the first page)

[Alyono]

and the 12Z GFS has dropped the idea of this becoming a CV hurricane. The 6Z GFS was likely out to lunch

[gatorcane]

You don't think the GFS might be struggling to predict genesis accurately because of how it is handling the interaction of pouch 17 and 18L? It seems it is flip-flopping each run with one run showing development, the next run, no development. I haven't seen a lot of consistency to say either way whether it will or won't develop.

[alienstorm]

This disturbance is really starting to have some spin, agreed that the interaction between these 2 pouches may be giving models fit. It will be interesting to see which one dominates.

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

[Hurricaneman]

This disturbance is really starting to have some spin, agreed that the interaction between these 2 pouches may be giving models fit. It will be interesting to see which one dominates.

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

the thing is I believe that if this one develops its going to be a fish but if pouch 017L develops its going to be a threat for US landfall or as some models are suggesting a merger between the 2 pouches and not much development due to that

The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products

[cycloneye]

Late to post this but here is the 2 PM TWD:

A TROPICAL WAVE CAME OFF THE WEST AFRICAN COAST EARLIER THIS
MORNING. CURRENTLY...ITS AXIS EXTENDS FROM 17N17W TO 9N16W WITH
AN EXPECTED MOTION OF 15 KT IN THE NEXT 24 HOURS. THE WAVE IS
EMBEDDED IN THE MONSOON TROUGH WHERE DEEP LAYER MOISTURE AND
UPPER-LEVEL DIFFLUENCE SUPPORT SCATTERED MODERATE CONVECTION
FROM 6N-16N E OF 20W.

[cycloneye]

Is possible that pouch 017L sacrifices in favor of pouch 018L? Time will tell but as the time of this post it looks good. Maybe we have later on an ASCAT pass to see what is there.

[TheStormExpert]

Do both of these pouches have a LLC or is it just Pouch 017L?

[cycloneye]

Do both of these pouches have a LLC or is it just Pouch 017L?

That is why an ASCAT pass over 018L would be very good to see how is the structure.

[cycloneye]

The most agressive model so far is NAVGEM that develops 018L.

[Alyono]

if this does develop, it may not even reach 50W before recurving

[SFLcane]

Sadly it looks like it would recurve rather quickly if it developes. Ridging looks fairly decent over NE Atl, but if there is trough in central Atlantic its goodbye.

[TheStormExpert]

:cry: Sadly it looks like it would recurve rather quickly if it developes. Ridging looks fairly decent over NE Atl, but if there is trough in central Atlantic its goodbye.

So how is that a sad thing? We don't want these systems (weak or strong) to affect land masses even Bermuda.

[cycloneye]

Still no bite by NHC.

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
800 PM EDT THU AUG 14 2014

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

Tropical cyclone formation is not expected during the next 5 days.

$$
Forecaster Brennan