Strong tropical wave off western Africa

[philnyc]

At what level does the African Easterly jet travel at, and what is considered a favorable value. For that matter, does it show up on the Dakar sounding? Anyone have a URL for that, BTW?



While we're at it, why would winds from the West in the stratosphere increase the probabilities of a major hurricane? (I've seen that mentioned for years, in places like Dr. Gray's seasonal outlooks, and wondered how it helped)

The Middle Level African Easterly Jet travels at 650mb typically. Since that's not a mandatory level, we usually use 600mb, although the NHC uses 700mb. It will definitely show up in the Dakar sounding; just pull a sounding and look at the 650mb wind readings.


As for your second question, you'd need to ask Dr. Gray. With all due respect, I don't understand very much of what he says.

[philnyc]

It is a true waste of time to track waves as they exit Africa... 95% of them don't turn into anything, and usually the best looking ones are destroyed by the SAL.

So we should never pay attention to them? Wouldn't we learn something from the ones that DO develop?

P.S. Your percentages are off.

[philnyc]

The current wave departing the African coastline has a better shot for development. I still see a vigorous mid-level spin - there is some evidence for a sfc low near 12N and 19W. SAL isn't a primary inhibitive factor, and shear is low - look at the latest imagery. You should play the loop. Convection is increasing over water - if the structural organization persists, it could become our next INVEST. Look at the fair upper-air support, too. What do you think?

Here is a recent EUMETSAT image.

Personally that scares me. There seems to be no end to these waves, and each succesive one looks better structurally than the previous one.

[MiamiensisWx]

Good points, Phil. You should consider the low-level convergence - obviously you and I monitor these trends! The latest IR imagery confirms my thoughts - a possible LLC may set up near the main mass of convection (greatest divergence and mid-level turning). The centrifugal force will play a key role. Let's see if the wave can detatch from the ITCZ - it's still within the deep monsoonal trough. I think it is possible to expect a new low near the primary area of concern (south of 13N). Look here. Loop the images - you will observe my point. I'll create a demonstration.

Latest image:



I'm sharpening my skills...

[MiamiensisWx]

More thoughts would be greatly appreciated. Some in-depth prognosis would provide benefits. Let's discuss the specific details. I think an INVEST by day four is a good estimate.

[philnyc]

I'm sharpening my skills

Good for you dude. But it's not the centrifugal force alone. It's the balance of the friction, coriolis, centrifugal and pressure-gradient forces of the incoming air parcels that determine whether the air will spin into the center or not. But we shouldn't get overwhelmed with that. Your original point is well-taken, and we can just watch it and visually assess whether these forces are balancing out - I believe that that's what the NHC guys are still doing at this "relatively" early point in our history of understanding these systems. There are no equations extant yet that will tell us whether the spin will hold or not. The best meteorologists can do right now for Cape Verde systems is measure the MLAEJ, the strength of the southwest monsoon winds, the amount of moisture and shear present (look at the skew-ts), and other local variables, and then determine through our "primitive" equations if all of the basic ingredients are looking positive or not. What that boils down to is that some of you guys are really good at saying a storm will develop when all of the experts get it wrong. Keep waching and teaching everybody else. There must be something you're seeing that the equations are not.
I really admire how much the severe storms experts for U.S. severe weather rely on storm-chasers and spotters. They realize the value of those guys. You "hurricane" guys who spend a huge amount of time watching satellite, radar and other data are "watchful eyes" that eventually tell the experts so much about what's really going on in these systems.

Having said that, I need a break. I'm burning out. But i do agree with you that we need to cover the details so we do the proper science. And you are really good at demanding to see the right science. I'm just falling out...

[MiamiensisWx]

Overnight convection has maintained itself - the system is located many miles from the African coast. Additionally, convection continues to pulse during the morning hours. Look here. The wave is generating convection in the afternoon (per time zones). That trend is an extremely positive sign. SAL is minimal - recent imagery indicates the demise of the stable air mass. The SAL is lessening its grip - look here. Mid-level rotation is vigorous, and there is a great moisture source. We have persistence, folks - I think this wave warrants attention. It looks VERY good. Its chrysallis of moisture has expanded to the west - that would support additional organization. The other factors remain favorable. I think our next INVEST will arrive within the next four days.



I think this wave has a better short-term chance than any other current system. It should receive attention. It is not "poofing" at all...

[MiamiensisWx]

This system could receive a TWO mention within a few days.

[Weatherfreak14]

The system does look pretty impressive and has enough juice all around it. I think this "bears" watching. LOL

[MiamiensisWx]

The system does look pretty impressive and has enough juice all around it. I think this "bears" watching. LOL

I think it is appropriate for the season. This system has a shot.

[HurricaneMaster_PR]

NHC 2:05pm Discussion

TROPICAL WAVE IS NEAR THE CAPE VERDE ISLANDS ALONG 23W S OF 22N
MOVING W 10 KT. A 1011 MB LOW IS EMBEDDED ON THE WAVE AXIS NEAR
14N23W. SCATTERED MODERATE CONVECTION IS FROM 15N-17N BETWEEN
20W-22W. WIDELY SCATTERED MODERATE CONVECTION IS FURTHER S
ALONG THE ITCZ FROM 7N-11N BETWEEN 18W-27W.

[RevDodd]

Tempus Fugit

[canegrl04]

So many weeks being bored with the tropics,and then just in time fr the beginning of peak season,we seem to be getting them all at once.Its possible we could have 3 named systems within the next 7 days

[cycloneye]

TROPICAL WAVES...
TROPICAL WAVE IS ALONG 23W S OF 20N WITH A 1010 MB LOW ALONG THE
WAVE NEAR 13N MOVING W 5-10 KT. BROAD MID LEVEL ROTATION COVERS
THE AREA FROM 10N-20N BETWEEN 20W-27W. SCATTERED SHOWERS AND
POSSIBLE ISOLATED THUNDERSTORMS ARE FROM 7N-15N BETWEEN
22W-27W.



8 PM Discussion by TPC.

[Normandy]

Looks like the wave really isn't as well organized anymore....slow development seems very likely. The wave I thought would develop has fizzled too (the one behind 99L) and looks like development wont happen there soon either.

Still give the wave that just left the African coast a small chance of development.

[Meso]