Two African waves worth mentioning

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

Share this Blog
2
+

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

Reader Comments

Comments will take a few seconds to appear.

Post Your Comments

Please sign in to post comments.

or Join

Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 900 - 850

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46Blog Index

well looks like a c
Member Since: Posts: Comments:
Earlier today, here

Member Since: Posts: Comments:
when do the new wind shear analysis maps come out again ??
Member Since: Posts: Comments:
Drak is going to go with C
Member Since: October 28, 2006 Posts: 57 Comments: 30562
Quoting nrtiwlnvragn:


No, just based on ex97L, so no development there and the previous TWO basically said no development by the islands, at least in the next 48 hours.
Wouldn't be the first time they had to change it. I remember several times one update said no development in the next 48 hrs and the next one said development possible in the next 48 hrs.
Member Since: Posts: Comments:
Nothing under the convection,.. its easy to see in the Vis,now fading to Night IR..run it full, speed and its easy to see.

Floater - Visible Loop
Member Since: July 3, 2005 Posts: 426 Comments: 128636
wunder twins de-activate
Member Since: Posts: Comments:
Quoting Patrap:
Floater 1 - Visible Loop

Running the Loop FAST shows the energy west of the Leewards pulling WEST.

The Convection over the Islands is waning and isnt the Player.


Picture would be a lot clearer if QuickScat would get it this evening. I've looked at loops, models, etc and can not find anything going on there Pat...But I also can't see through the large blob of convection to tell if anything is going on in the lower levels...
Member Since: August 17, 2005 Posts: 26 Comments: 16854
i vote both yellows remain
Member Since: Posts: Comments:
Okay...I already stated it earlier...B
Member Since: Posts: Comments:
A
Member Since: Posts: Comments:
Quoting WxLogic:


Ohh ohh... I think nrt... knows something we don't know. I was going to pick A too, but didn't wanted to be too aggressive. Hehe...


No, just based on ex97L, so no development there and the previous TWO basically said no development by the islands, at least in the next 48 hours.
Member Since: Posts: Comments:
Quoting BurnedAfterPosting:


pick only one answer lol

one yellow and one orange
Member Since: Posts: Comments:
I go with C
Member Since: Posts: Comments:
886. JRRP
16n
64w
Link
Member Since: Posts: Comments:
Floater 1 - Visible Loop

Running the Loop FAST shows the energy west of the Leewards pulling WEST.

The Convection over the Islands is waning and isnt the Player.
Member Since: July 3, 2005 Posts: 426 Comments: 128636
Quoting nrtiwlnvragn:
845. BurnedAfterPosting

A


Ohh ohh... I think nrt... knows something we don't know. I was going to pick A too, but didn't wanted to be too aggressive. Hehe...
Member Since: Posts: Comments:
This isnt any system anywhere in the Basin.

Just a Few T-waves and a possible Surface/Mid level circ in the Eastern Caribbean
Member Since: July 3, 2005 Posts: 426 Comments: 128636
Quoting hunkerdown:
B is one yellow disappears...


Yeah, fixed that lol, thanks though :)
Member Since: July 1, 2008 Posts: 13 Comments: 7396
Quoting BurnedAfterPosting:
ok time for a game

which is the most likely scenerio for the 8pm TWO

A) Both yellow circles go away
B) One yellow circle goes away, one remains
C) Both yellow circles remain
D) One of the yellow circles becomes and orange circle.

Vote now!!


Didn't last year someone come up with the STUPID CIRCLE that would encompass the entire area?? I'll go with E. Stupid Circle! which would be yellow and include both current circles.
Member Since: Posts: Comments:
Severe weather alert just issued for Weston, Davie, Plantation areas... severe storm, lightning, winds to 70mph and damaging hail

Quoting plywoodstatenative:
Heavy rain and lightning here in Broward County
Member Since: Posts: Comments:
Quoting BurnedAfterPosting:
I am keeping a vote tally lol

right now B and C both have 2 votes apiece
I vote C
Member Since: Posts: Comments:
878. amd
Quoting BurnedAfterPosting:
ok time for a game

which is the most likely scenerio for the 8pm TWO

A) Both yellow circles go away
B) One yellow circle goes away, one remains
C) Both yellow circles remain
D) One of the yellow circles becomes and orange circle.

Vote now!!


B
Member Since: Posts: Comments:
Quoting Patrap:
As a staunch independent I never vote on Saturday's.
Sorry
What about Sundays ?
Member Since: Posts: Comments:
vote C..
Member Since: August 30, 2007 Posts: 0 Comments: 1857
Ok we've had A, B, and C picked. D anyone??
Member Since: Posts: Comments:
Quoting HurricaneSwirl:


Sweet. Actually now that i look back 456 posted a shear map that was for the 24th. im pretty sure the system will be up near the carolinas by that time. the time where it actually passes through the bahamas there will be high shear.


Right.
Member Since: October 28, 2006 Posts: 57 Comments: 30562
Quoting reedzone:
B. Both yellow circles stay 80% confident!
B is one yellow disappears...
Member Since: Posts: Comments:
Quoting Drakoen:


In regards to the shear.


Sweet. Actually now that i look back 456 posted a shear map that was for the 24th. im pretty sure the system will be up near the carolinas by that time. the time where it actually passes through the bahamas there will be high shear.
Member Since: Posts: Comments:
845. BurnedAfterPosting

A
Member Since: Posts: Comments:
Quoting HurricaneSwirl:


C


I think B.
Member Since: Posts: Comments:
C. Both yellow circles stay 80% confident!
Member Since: July 1, 2008 Posts: 13 Comments: 7396
Quoting Weather456:
It could be B or C, but my final answer is C, lol
see post 829
Member Since: Posts: Comments:
Quoting victoria780:
both yellow

both yellow
Member Since: May 16, 2009 Posts: 1 Comments: 1231
As a staunch independent I never vote on Saturday's.
Sorry
Member Since: July 3, 2005 Posts: 426 Comments: 128636
Quoting wunderkidcayman:
one of yellows circle becomes orange maybe if not two yellows


pick only one answer lol
Member Since: Posts: Comments:
Quoting WxLogic:


Hehe... since there's still some potential until DMAX tomorrow AM... I'll go with:

B
both yellow
Member Since: Posts: Comments:
Quoting HurricaneSwirl:


analysis? are you calling me a manwoman too...
or is it the shear one XD


In regards to the shear.
Member Since: October 28, 2006 Posts: 57 Comments: 30562
Quoting Weather456:
It could be B or C, but my final answer is C, lol


lol
Member Since: Posts: Comments:
Quoting BurnedAfterPosting:
ok time for a game

which is the most likely scenerio for the 8pm TWO

A) Both yellow circles go away
B) One yellow circle goes away, one remains
C) Both yellow circles remain
D) One of the yellow circles becomes and orange circle.

Vote now!!
one of yellows circle becomes orange maybe if not two yellows
Member Since: Posts: Comments:
It could be B or C, but my final answer is C, lol
Member Since: Posts: Comments:
Quoting Drakoen:
Hurricaneswirl you were correct in your analysis.


analysis? are you calling me a manwoman too...
or is it the shear one XD
Member Since: Posts: Comments:
858. HadesGodWyvern (Mod)
Hong Kong Observatory

Tropical Cyclone Warning

The typhoon Molave (0906) has weakened into a Severe
Tropical Storm with central pressure 980 hectopascals. At
182100 UTC, it was centred within 30 nautical miles of two
two point seven degrees north (22.7 N) one one three point
five degrees east (113.5 E) and is forecast to move west at
about 14 knots for the next 24 hours.

Maximum winds near the centre are estimated to be 55 knots.
Member Since: Posts: Comments:
Quoting BurnedAfterPosting:
ok time for a game

which is the most likely scenerio for the 8pm TWO

A) Both yellow circles go away
B) One yellow circle goes away, one remains
C) Both yellow circles remain
D) One of the yellow circles becomes and orange circle.

Vote now!!


Hehe... since there's still some potential until DMAX tomorrow AM... I'll go with:

B
Member Since: Posts: Comments:
I am keeping a vote tally lol

right now B and C both have 2 votes apiece
Member Since: Posts: Comments:
Heavy rain and lightning here in Broward County
Member Since: Posts: Comments:
853. HadesGodWyvern (Mod)
Tropical Cyclone Bulletin

Here is the latest Tropical Cyclone Bulletin issued by the
Hong Kong Observatory.

The Strong Wind Signal, No. 3 was issued at 6:40 a.m.

This means that winds with mean speeds of 41 to 62
kilometres per hour are expected.

The strong winds associated with Molave will continue to
affect Hong Kong for a short while. There will be
occasional heavy rain and squalls. The strong wind Signal,
No. 3 will remain in force for some time.
In the past hour, the maximum sustained winds recorded at
Cheung Chau and Chek Lap Kok were 62 and 51 kilometres per
hour respectively.
Member Since: Posts: Comments:
Hurricaneswirl you were correct in your analysis.
Member Since: October 28, 2006 Posts: 57 Comments: 30562
Quoting hunkerdown:
B
Both yellow
Member Since: Posts: Comments:
Quoting BurnedAfterPosting:
ok time for a game

which is the most likely scenerio for the 8pm TWO

A) Both yellow circles go away
B) One yellow circle goes away, one remains
C) Both yellow circles remain
D) One of the yellow circles becomes and orange circle.

Vote now!!


C
Member Since: Posts: Comments:

Viewing: 900 - 850

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46Blog Index

Top of Page

About

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