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 reedzone:
The remnants of 97L are actually making a comeback

Photobucket

Banding features are "trying" to form to the north. DMAX is currently doing this storm good, it's also now entered a much better environment. I will be watching this closely throught the night.


Reedzone Invest eh?
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Quoting reedzone:
The remnants of 97L are actually making a comeback

Photobucket

Banding features are "trying" to form to the north. DMAX is currently doing this storm good, it's also now entered a much better environment. I will be watching this closely throught the night.


DMAX is a long long way away for this storm
The remnants of 97L are actually making a comeback

Photobucket

Banding features are "trying" to form to the north. DMAX is currently doing this "wave" good, it's also now entered a much better environment. I will be watching this closely throught the night.
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Quoting Drakoen:
EX-97L just has a weak mid level circulation confirmed by shortwave visible imagery and cimss 850mb vorticity.


During he last 3 to 6 hours it appears to be trying to consolidate/generate a mid level 500MB vort max. This might explain so of the TSTM re-firing that it has been experiencing during the last couple ours.
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Saint Thomas, Virgin Islands wu-page


Member Since: July 3, 2005 Posts: 426 Comments: 129093
wow, the 30-50 knots of shear really did in the Caribbean blobb!!!!
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Quoting BurnedAfterPosting:
For those who are lurking

There is NO 98L, do not get confused by people who keep referring to a new invest, there isnt one

Also 97L was deactivated, it no longer exists as an invest.


Both areas look rather meager at this point, there isnt very much to look at in the tropics, at least for tonight anyway.


I am not sure I agree.. looking at
977. GeoffreyWPB 12:19 AM GMT on July 19, 2009

I'm gonna call my sister on st. thomas that cell heading her way is bigger than the island. They are in for some weather tonight.
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EX-97L just has a weak mid level circulation confirmed by shortwave visible imagery and cimss 850mb vorticity.
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991. Mikla
ex97 with 21:00 UTC Shear Tendency Map. Dotted line is decreasing, Solid is increasing based on last 24 hours...
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latest QS pass of X-97...




Click image to see entire area.
Member Since: August 17, 2005 Posts: 26 Comments: 16874
I am already right...it is dissapating!
Member Since: May 16, 2009 Posts: 0 Comments: 684
Just look at the infrared satellite image
Quoting StormFreakyisher:

Proof?
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Quoting Patrap:
May be a FF ans w-server too Drak. Im still getting that too,but no longer being signed out every post. That was driving me to drink earlier.LOL


I never did get signed out but that was starting to drive me up the walls
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Quoting hurricane556:
97L is making a comeback

Proof?
Member Since: May 16, 2009 Posts: 0 Comments: 684
so, anyone think either one of these waves will do anything? They say they are worth mentioning,but at the same time expect nothing to happen with them. hmmmmmmmm
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May be a FF and wu-server too Drak.
Im still getting that too,but no longer being signed out every post. That was driving me to drink earlier.LOL
Member Since: July 3, 2005 Posts: 426 Comments: 129093
Quoting StormFreakyisher:

Why is it still on the weatherunderground site temperature map?


because they are always slow to update, nrti showed the offical deactivation of the invest earlier
97L is making a comeback
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Quoting Patrap:
CRS,if your running FireFox 3,there is a updated fix for that..try a restart/re-boot.
It worked for me earlier today.


It is still doing that for me even with the upgrade.
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Quoting BurnedAfterPosting:
For those who are lurking

There is NO 98L, do not get confused by people who keep referring to a new invest, there isnt one

Also 97L was deactivated, it no longer exists as an invest.


Both areas look rather meager at this point, there isnt very much to look at in the tropics, at least for tonight anyway.

Why is it still on the weatherunderground site temperature map?
Member Since: May 16, 2009 Posts: 0 Comments: 684
CRS,if your running FireFox 3,there is a updated fix for that..try a restart/re-boot.
It worked for me earlier today.
Member Since: July 3, 2005 Posts: 426 Comments: 129093
For those who are lurking

There is NO 98L, do not get confused by people who keep referring to a new invest, there isnt one

Also 97L was deactivated, it no longer exists as an invest.


Both areas look rather meager at this point, there isnt very much to look at in the tropics, at least for tonight anyway.
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ECMWF Forecast Models:
Member Since: July 3, 2005 Posts: 426 Comments: 129093
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974. Relix
Darn, getting some strong rain here in PR from 98L (just in case =P).
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Maybe the one near the Antilles that is waning out will just fade out and tomorrow will have to struggle as an disorganized showers while still in shear and become like what was Invest 97L.
Member Since: May 16, 2009 Posts: 0 Comments: 684
Quoting Tazmanian:



that navy site has not updateed for a long long time they are showing 97L be come they have not updateed it yet too re move it


you want this one it more updated on this navy site you see 97L is in fac gone


Link
Thanks Taz, I have now updated my link. Much appreciated.
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Quoting centex:
Notice they expaned to southern Caribbean now.



tc formation has decreased considerably compared to earlier this afternoon.
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Notice they expaned to southern Caribbean now.

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Knowing the strange numbering lately, im betting our AOI will be 96L, that would make me confused but heck.
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Quoting Tazmanian:



that navy site has not updateed for a long long time they are showing 97L be come they have not updateed it yet too re move it


you want this one it more updated on this navy site you see 97L is in fac gone


Link


The NHC made a good call in leaving the circle up for it. Convection (band like) is developing northeast of the 2 bubbles of convection. It's trying to get going now, tonights going to be interesting.
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Quoting KEHCharleston:
Navy shows 97L no 98L yet

RE:960. StormFreakyisher

Yikes!



that navy site has not updateed for a long long time they are showing 97L be come they have not updateed it yet too re move it


you want this one it more updated on this navy site you see 97L is in fac gone


Link
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Quoting KEHCharleston:
Navy shows 97L no 98L yet

RE:960. StormFreakyisher

Yikes!


it generally can take some time especially on weekends for the navy site to update properly
Navy shows 97L no 98L yet

RE:960. StormFreakyisher

Yikes!
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Quoting StormFreakyisher:
Here is right before the severe storm I had over my house in Boca Raton.Scary.
Nasty looking weather.
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Quoting Tazmanian:
we lot see any thing in lat AUG or SEP if not at all


how about we dont get carried away there, it is July 18th, long way to go in the season

we lot see any thing in lat AUG or SEP if not at all
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Here is right before the severe storm I had over my house in Boca Raton.Scary.
Member Since: May 16, 2009 Posts: 0 Comments: 684
A TROPICAL WAVE IS ALONG 45W/46W S OF 18N MOVING W NEAR 20 KT.
LOW TO MID-LEVEL CYCLONIC TURNING IS NOTED IN VISIBLE SATELLITE
IMAGERY.THIS WAVE ALSO COINCIDES WITH A LOW AMPLITUDE DEEP LAYER
MOISTURE MAXIMUM OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY.
SCATTERED MODERATE CONVECTION IS FROM 11N-13N BETWEEN 46W-49W.

A TROPICAL WAVE EXTENDS FROM 21N61W TO 11N63W MOVING W NEAR 18
KT. THIS WAVE COINCIDES WITH A DEEP LAYER MOISTURE MAXIMUM
OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. RADAR IMAGERY FROM
PUERTO RICO INDICATES NE FLOW W OF THE WAVE AXIS AS IT
APPROACHES THE ISLAND FROM THE E. SCATTERED MODERATE CONVECTION
IS E OF THE WAVE AXIS FROM 12N-18N BETWEEN 56W-62W. THIS
CONVECTION IS BEING ENHANCED BY UPPER LEVEL DIFFLUENCE.

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Quoting Patrap:
Maybe you should try that preview button,.. it might save ya some embarrassment one day


why because I quoted the wrong post?

LOL talk about an overreaction there, not everyone can be as perfect as you
Quoting Seflhurricane:
well looks like we have another contendor to watch impressive wave coming off africa


950. FloridaTigers 11:50 PM GMT on July 18, 2009
Quoting HurricaneSwirl:

it'll choke on some of that dry air just to the north

Looks like ex-97L moistened the environment in the central Atlantic though.




yea but that large area of SAL coming off Africa will dry it back up again

looks like the CATL and EATL are shut down again, no development there

situational development closer to home is your only shot at Ana for the month of July it looks like

Sorry to be the bearer of bad news lol
Quoting Patrap:
Er,the Poster was referring to the "GOM", Burned dude..LOL


I quoted the wrong person lmao
Pat,

Maybe the models have been right all along with that GOM disturbance. Im watching.
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Er,the Poster AllStar17 was referring to the "GOM", Burned dude..

LOL,sorry to be the bearer of bad news fer yas
Member Since: July 3, 2005 Posts: 426 Comments: 129093
oops lol
Always be wary of the Tail end of a Front in Mid to Late July,..the GOM is Primed and one can get a Low to Form and well,off to the races then.

Earlier NAM show GOM Cyclogenesis and Up and away!!!!

Member Since: July 3, 2005 Posts: 426 Comments: 129093
Quoting HurricaneSwirl:


it'll choke on some of that dry air just to the north



Looks like ex-97L moistened the environment in the central Atlantic though.
Member Since: May 17, 2009 Posts: 0 Comments: 559

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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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