Two African waves worth mentioning

By: Dr. Jeff Masters , 3:51 PM GMT on July 18, 2009

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There are two African tropical waves worth mentioning today, though neither looks particularly threatening. A tropical wave near 12N 45W, about 1200 miles east of the Lesser Antilles Islands (97 L), is moving west at 15 - 20 mph. This wave is now surrounded by an area of very dry air from the Sahara Desert. The dry air has disrupted most of the wave's heavy thunderstorm activity, and will continue to make it difficult for this system to develop over the next 2 - 3 days. Wind shear is a modest 10 knots over the disturbance, and should remain in the moderate 10 - 15 knot range over the next 2 - 3 days. Thereafter, shear is expected to rise to 20 - 30 knots. This morning's QuikSCAT pass showed no evidence of a surface circulation, and only a modest wind shift associated with 97L. The National Hurricane Center is giving this system a low (less than 30% chance) of developing into a tropical depression in the next 48 hours.

A second tropical wave now approaching the northern Lesser Antilles Islands is under 30 knots of wind shear, and has little prospect of development due to the high shear. However, the wave will bring heavy rain to the islands over the next two days.

None of the computer models are forecasting tropical storm development over the next seven days, and I don't expect either of the two African waves mentioned today to develop over at least the next three days.


Figure 1. Current satellite image of African wave 97L, 1200 miles east of the Lesser Antilles Islands.

I'll have an update Sunday afternoon.
Jeff Masters

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Quoting popartpete:
To me, it seems that 97l has really blossomed in the last few hours.

It's in a nice moist environment
Member Since: May 16, 2009 Posts: 1 Comments: 1231
Quoting weatherwatcher12:

Hello


Hey
Member Since: July 24, 2005 Posts: 407 Comments: 19076
1598. HadesGodWyvern (Mod)
Central Pacific Hurricane Center: Honolulu, Hawaii

Tropical Cyclone Outlook (4:00 PM HST 18JUL)
==============================================
An area of thunderstorm (91C) is located 600 miles south of Hilo, Hawaii moving west-northwest at 25 mph. Over the past 6 hours this area has shown signs of increased organization. Additional development may be possible over the next two days.
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Quoting Weather456:
Talk about combacks


Lol..Good morning 456.
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It is making a good comeback
Member Since: May 16, 2009 Posts: 1 Comments: 1231
To me, it seems that 97l has really blossomed in the last few hours.
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Quoting Weather456:
Talk about combacks

Hello
Member Since: May 16, 2009 Posts: 1 Comments: 1231
Talk about combacks
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Still no CIMSS update
Member Since: May 16, 2009 Posts: 1 Comments: 1231
Quoting popartpete:


I thought under 12 knots was considered favorable also. Remember the wording "significant development at this time", which does not equate to it being ripped apart by shear, and it also states the convection has increased. I'm not writing off 97L just yet.

I was being sarcastic lol :)
Member Since: May 16, 2009 Posts: 1 Comments: 1231
Quoting popartpete:


I thought under 12 knots was considered favorable also. Remember the wording "significant development at this time", which does not equate to it being ripped apart by shear, and it also states the convection has increased. I'm not writing off 97L just yet.


Sarcasm lol.
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Quoting weatherwatcher12:

A hard 10 knots of shear?


I thought under 12 knots was considered favorable also. Remember the wording "significant development at this time", which does not equate to it being ripped apart by shear, and it also states the convection has increased. I'm not writing off 97L just yet.
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1588. voca21
Proponents of the THEORY of human induced Global Warming will selectively publish data that supports their argument. They will not publish data that refutes it. Here we have another case in point. This blog has ignored the fact that currently Peru has issued a state of emergency due to abnormally cold winter temperatures as well as the fact that Manhattan has experienced its coldest June since 1958, Phoenix has had its coldest June since 1913, the Yucca Valley June average was 8 degrees below average and Boston had its lowest June maximum temperatures since 1872.
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thanks
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Quoting stormsurge39:
does decrease mean good for it?

No an increase is good for it
Member Since: May 16, 2009 Posts: 1 Comments: 1231
Quoting stormsurge39:
does decrease mean good for it?


Decrease is bad. Especially for a weak 'system'.
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Another wave rolled off the coast of Africa:
Member Since: May 16, 2009 Posts: 1 Comments: 1231
does decrease mean good for it?
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Quoting stormsurge39:
what does that mean stormchaser 850?


The lower level circulation strength. Although you are right in saying that the convection is the strongest its had.
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Quoting stormsurge39:
what does that mean stormchaser 850?

It gives us an indication of how strong it is at the surface if I am not mistaken.
Member Since: May 16, 2009 Posts: 1 Comments: 1231
what does that mean stormchaser 850?
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Quoting stormsurge39:
Ex97 is stronger than ever.



Not internally...the 850mb vort has decreased. We'll see what it looks like with the new update.
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D-Max is approaching:
Member Since: May 16, 2009 Posts: 1 Comments: 1231
Ex97 is stronger than ever.
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Current SST's look favorable:
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Quoting Stormchaser2007:


I know everything...

Although the URL that was embedded in the post helped a bit. lol

lol
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Quoting weatherwatcher12:

Lol how did you know


I know everything...

Although the URL that was embedded in the post helped a bit. lol
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Quoting Stormchaser2007:


Alright lets give that image a rest lol.

Heres what you were trying to post...



Lol how did you know
Member Since: May 16, 2009 Posts: 1 Comments: 1231
Quoting weatherwatcher12:


Alright lets give that image a rest lol.

Heres what you were trying to post...pretty old image doesnt do much good.


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Member Since: May 16, 2009 Posts: 1 Comments: 1231
Quoting btwntx08:

alright stormchaser oops i actually didn't want to put it in the last post i did but let me see i guess i'll modify if i can lol
Itchy trigger finger ?? I have heard of the blog eating posts, but not duplicating them.
Member Since: August 15, 2008 Posts: 0 Comments: 2515
Quoting weatherwatcher12:


Looks to be going due west

Member Since: May 16, 2009 Posts: 1 Comments: 1231

Looks to be going due west
Member Since: May 16, 2009 Posts: 1 Comments: 1231
Shear maps and everything else should update before 3am.
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Right now there is not enough shear on ex97 to be causing an uplift. my 5 year can look at the sat picture an see that. The shear in front of it will dye down enough to give it a chance,and right now it is looking pretty good,without wind shear causing a "blowup"!
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Quoting TampaSpin:
Ok i give up....going to bed! Have a great remainder of an early morning. Sorry if i came across Rude! Remember there isn't even an Invest at this point. Wonder Why?
Pleasant dreams of the 2008 World Series :)
Member Since: August 15, 2008 Posts: 0 Comments: 2515
Ok i give up....going to bed! Have a great remainder of an early morning. Sorry if i came across Rude! Remember there isn't even an Invest at this point. Wonder Why?
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Quoting btwntx08:

10 kts of shear and yes there is higher shear ahead but thats forecast to move north imo


Why do you put 'imo' next to every one of your posts if what you're saying is actually happening? You know what it means right lol? Not bashing you but im just saying feel confident in your posts...
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Quoting btwntx08:

10 kts of shear i don't think so besides the real ahead of it will be decreasing imo
i was being sarcastic...
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Quoting TampaSpin:


The blow is caused by an increase in shear causing an uplift!

The modest 10 knots?
Member Since: May 16, 2009 Posts: 1 Comments: 1231
Quoting btwntx08:

10 kts of shear i don't think so besides the real ahead of it will be decreasing imo


Sarcasm lol
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Quoting TampaSpin:


I'm sorry if im coming across Rude! But, i'm sorry you can't see the strong Shear starting to hit 97L....That's not being rude! Just trying to make my point what you see vs. what i see.......Point of fact! Your saying you disagree with NHC also. OK!
And we all know the NHC is perfect in their wording and decisions (people say it on here all the time that they are not classifying/naming when they should)...so tell me, if they are so right all the time, why do they currently have a yellow circle in the area of 63W ?
Member Since: August 15, 2008 Posts: 0 Comments: 2515
Quoting btwntx08:
ex 97 is blowing up quite nicely


The blow is caused by an increase in shear causing an uplift!
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Member Since: May 16, 2009 Posts: 1 Comments: 1231

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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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