The latest about wave at east atlantic

[cycloneye]

This is from the 8:05 AM discussion about this impressive wave:
.
TROPICAL WAVE ALONG 19W/20W S OF 20N MOVING W 10 KT. EXTREMELY
WELL DEFINED BROAD AREA OF LOW TO MIDDLE LEVEL ROTATION NOTED IN
MORNING VISIBLE IMAGERY AS WELL AS SURFACE OBSERVATIONS FROM THE
W AFRICAN COAST...THE CAPE VERDE ISLANDS...AND THE FEW SHIPS
REPORTING IN THE REGION. CONVERGENT LOW LEVEL NLY FLOW...W OF
THE WAVE AXIS...IS BUMPING UP AGAINST THE ITCZ HELPING TO
ENHANCE SCATTERED MODERATE CONVECTION FROM 19W TO 27W WITHIN THE
ITCZ. ADDITIONALLY...LOCALIZED CLUSTERS OF MODERATE CONVECTION
ARE STRUGGLING TO DEVELOP NEAR THE MEAN CLOUD SYSTEM CENTER FROM
9N TO 12N BETWEEN 17W AND 23W.

It is moving slower than many of the waves that haved emerged Africa in past weeks.But it will pick speed as it moves more west and gets caught with the east flow.Also to have invest 96L for this system first convection has to develop near the low as Derecho said in another thread.And this morning it looks not too healthy as before as convection is now confined to the ITCZ south of 10n.

[Renata]

This wave is a real embryo ... lots of development to go through before it can start to develop.

[cycloneye]

Yes agree it will take a while for it to develop if it does at all.

[Rainband]

Looks like it's being sheared . It has time but it won't happen anytime soon

[Guest]

More potential for landfalls. I thought for sure this wave would develp yesterday.

[obxhurricane]

I don't see any shear????

I see a healthy, well organized, classic, Cape Verde system in it's early formative stages. Look for Frances to be passing north of the Islands in a week.

[Renata]

I don't see any shear????

Strong shear over the wave now (see: http://cimss.ssec.wisc.edu/tropic/real- ... m7shr.html). shear is a little lighter upahead around 30W.

Forecast is for the shear to decrease. So at least that aspect of the environment will become friendlier in the next 24 hours or so and the baby embryo might start growing!

[Anonymous]

This wave is a real embryo ... lots of development to go through before it can start to develop.

Is abortion an option for possibly future Frances?

According to this map, shear is very light in the East Atlantic...

[Renata]

According to this map, shear is very light in the East Atlantic...

Hiya Jekyhe,

This isn't a map of the eastern Atlantic. It is the western Atlantic and does not show the area of the wave under question.

Post the correct map if you want to talk.

Renata

[DoctorHurricane2003]

Renata, you are incorrect......the wave is located near 8.5 N 25 W.....well within the lower right hand block

[Thunder44]

This is from the 5:30pm TWO:

Cloudiness and thunderstorms associated with a tropical wave a few
hundred miles south of the Cape Verde Islands have become a little
better organized this afternoon. This system has some potential
for development over the next couple of days as it moves westward.

[Brent]

This is from the 5:30pm TWO:

Cloudiness and thunderstorms associated with a tropical wave a few
hundred miles south of the Cape Verde Islands have become a little
better organized this afternoon. This system has some potential
for development over the next couple of days as it moves westward.

Maybe something will develop! August 28th is when Fabian formed last year. Will we beat that?

[Renata]

Renata, you are incorrect......the wave is located near 8.5 N 25 W.....well within the lower right hand block

Hi Doc,

At the time (1:39 pm) that Jekyhe32210 posted the map the axis of the wave was located along 21W (as per the TWD 2:05 pm)

TROPICAL WAVE IS ALONG 21W S OF 20N MOVING W 10 KT. WELL DEFINED
BROAD AREA OF LOW TO MIDDLE LEVEL ROTATION IS NOTED IN VISIBLE
IMAGERY. SCATTERED MODERATE CONVECTION IS FROM 11N-13N BETWEEN
19W-21W...AND FROM 8N-11N BETWEEN 24W-26W. WIDELY SCATTERED
MODERATE CONVECTION IS 4N-8N BETWEEN 18W-28W.

That is on the right hand edge of the map (which is the western Atlantic map and not the eastern Atlantic map - that was my contention) and therefore it is more appropriate to refer to the Wind Shear map below which shows a 30KT shear from around 30W back to the coast of Africa.

Also pertinent to the discussion is the thread found at: http://www.storm2k.org/phpbb2/viewtopic ... 051#617793

Renata

http://cimss.ssec.wisc.edu/tropic/real-time/europe/winds/wm7shr.html:

[x-y-no]

That is on the right hand edge of the map (which is the western Atlantic map and not the eastern Atlantic map - that was my contention) and therefore it is more appropriate to refer to the Wind Shear map below which shows a 30KT shear from around 30W back to the coast of Africa.

OK, now I'm really confused. How can the two maps show such radically different shear for the same time period and location?

Looking at the area between 20W and 30W and between 5N and 10N, the West atlantic map show less than 5 knots shear, while the East Atlantic/Africa map shows something between 20 and 30 knots shear.

Are we to think that these maps are totally inaccurate at their boundaries? Why should that be?

Both maps are labelled "18:00 UTC 22AUG04". The only difference I can see is that one is labelled "24 hour wind shear tendency" while the other one is "wind shear". Is that the difference, and even so how is one then to understand these numbers?


EDIT: Hang on ... I think I may be answering my own question ... sorta

There's a link for "shear tendency" on the East Atlantic/Africa page, and clicking that gives a map whose numbers match those of the West Atlantic map.

So the question is which of these numbers: "wind shear" or "wind shear tendency" is the meaningful one in terms of how a system is affected?

[obxhurricane]

You guys can look at all the charst you want, but with my TRAINED eye I'm telling you it looks to me like there is little to no shear over the ERN Atlantic.

In any case...conditions are favorable for development during the next few days as this system continues generally westward...thus look for slow yet steady strengthening into a TC during the next 24-48 hours.

[Brent]

Compared to this morning, this system looks like Frances. It was basically devoid of convection earlier. I defintely think it will be named in the next few days, shear or not.

[x-y-no]

You guys can look at all the charst you want, but with my TRAINED eye I'm telling you it looks to me like there is little to no shear over the ERN Atlantic.

OK ... I'm the first to admit I don't have a particularly "trained eye". Right now, I was just trying to understand the numbers I was looking at on these charts. Can you help me out?

[cycloneye]

If the trend of convection increasing continues we can expect 96L invest to be up by tommorow morning.

[x-y-no]

Still tring to answer my own question ...

I see that "wind shear tendency" on that site is defined as "24 hour change in shear magnitude." So it seems that that's not the meaningful number for judging the current environment, but in combination with the absolute shear map could indicate the future environment of a system.

So my next question is, does the fact that the direction of the shear on the "wind shear" chart is more or less the same as the movement of the system mean that it's impact will be less?