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: 950 - 900

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

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: Posts: Comments:
Quoting Patrap:
NexSat GOM Loop,Visible


Pat, IMO we need to watch this area in case a low were to form. Your thoughts?
Member Since: Posts: Comments:
Big storm entering my area, clouds look dark, but awesome.. Here's the radar.. currently I'm only under a Special Weather Statement. Though that can quickly turn into a warning at any time.

http://radar.weather.gov/radar.php?rid=jax&product=N0R&overlay=11101111&loop=no
Member Since: July 1, 2008 Posts: 13 Comments: 7390
Quoting Seflhurricane:
one more game for ex97L

A) Dissipates tonight
B) explodes/better organized overnight
C) gets better organized and remains the same
D) none of the above


I'll go with C
Quoting Seflhurricane:
well looks like we have another contendor to watch impressive wave coming off africa


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

Member Since: Posts: Comments:
NexSat Africa and Eastern Atlantic
Member Since: Posts: Comments:
NexSat GOM Loop,Visible
Member Since: Posts: Comments:
Quoting Patrap:
GOES-12 Channel 3 (WV)
well looks like we have another contendor to watch impressive wave coming off africa
Member Since: Posts: Comments:
Quoting Seflhurricane:
one more game for ex97L

A) Dissipates tonight
B) explodes/better organized overnight
C) gets better organized and remains the same
D) none of the above
C
Member Since: Posts: Comments:
Yeah them Banana Leaves were really getting Pounded under Partly cloudy skies..LOL
Member Since: Posts: Comments:
940. JRRP
Quoting Seflhurricane:
one more game for ex97L

A) Dissipates tonight
B) explodes/better organized overnight
C) gets better organized and remains the same
D) none of the above

A
Member Since: August 16, 2007 Posts: 0 Comments: 5816
Quoting Seflhurricane:
one more game for ex97L

A) Dissipates tonight
B) explodes/better organized overnight
C) gets better organized and remains the same
D) none of the above


C
Member Since: Posts: Comments:
Link
Look at wind gust!!
Member Since: May 16, 2009 Posts: 0 Comments: 684
Quoting Patrap:
Taps for 97L..


WOW.. that always gives me goosebumps..

And I was wrong. It's actually the STOOPID Circle..
Member Since: Posts: Comments:
Quoting Patrap:
GOES-12 Channel 3 (WV)
Member Since: Posts: Comments:
935. JRRP
Quoting Weather456:
Earlier today, here


Amazing video
Member Since: August 16, 2007 Posts: 0 Comments: 5816
personally i believe C is the best answer its going to get better organized when the shear relaxes in a couple of days and it crosses the islands
Member Since: Posts: Comments:
So is it still 97L? or is it ex 97L...lol. Im confused.
Member Since: Posts: Comments:
932. Miami
I vote for C.....
Member Since: Posts: Comments:
BOCA RATON AIRPORT AUTHORITY:
WIND:30
GUST:45
Member Since: May 16, 2009 Posts: 0 Comments: 684
GOES-12 Channel 3 (WV)
Member Since: Posts: Comments:
Well looks like C won, good job everyone and thanks for playing :P
Taps for 97L..
Member Since: Posts: Comments:
Quoting Seflhurricane:
one more game for ex97L

A) Dissipates tonight
B) explodes/better organized overnight
C) gets better organized and remains the same
D) none of the above


I'm gonna say C. gets better organized but remains the same invest it is. None of these "invests" will form until it reaches low shear which according to most models won't be until 96-100 hours after it crosses into the Bahamas.
Member Since: July 1, 2008 Posts: 13 Comments: 7390
Quoting Seflhurricane:
one more game for ex97L

A) Dissipates tonight
B) explodes/better organized overnight
C) gets better organized and remains the same
D) none of the above

hopefully BBBBBBBBBBBBBBBBBBB.
Member Since: Posts: Comments:
I think I'll go with Z. LOL
Member Since: Posts: Comments:
hey wheres it gonna hit
Member Since: Posts: Comments:
Quoting Seflhurricane:
one more game for ex97L

A) Dissipates tonight
B) explodes/better organized overnight
C) gets better organized and remains the same
D) none of the above


im gonna have to go with C yet again :)
but not much better organized
Member Since: Posts: Comments:
Quoting FTLGUY:
We are getting pounded here in Broward

we can use some rain here in south MIami- Dade county
Member Since: Posts: Comments:
ex-97 will refire and will be back on the maps sat and models when dmax starts ummm when will the dmax come and refire ex-97
Member Since: Posts: Comments:
Wah,..wahhhhh

No 97L..only a memory..

Tropical Floater Imagery
Member Since: Posts: Comments:
We are getting pounded here in Broward

Quoting StormFreakyisher:
Anyone else getting these severe storms in Palm Beach county?
Member Since: Posts: Comments:
PBIA: Wind Speed: W 36 G 54 MPH

Wow...who needs a tropical storm....
Member Since: Posts: Comments:
Quoting stormwatcherCI:
Did you have much rain ?


Nope, less than an inch. More of a windy day.
Member Since: Posts: Comments:
one more game for ex97L

A) Dissipates tonight
B) explodes/better organized overnight
C) gets better organized and remains the same
D) none of the above
Member Since: Posts: Comments:
B
Member Since: May 16, 2009 Posts: 0 Comments: 684
C! :)
Member Since: October 28, 2006 Posts: 57 Comments: 30491
Yep, the NHC would of announced they dropped 97L. Also they shifted the floater to the carib blob, likely they did that for no reason. The reason for C
Member Since: Posts: Comments:
Quoting Weather456:
Earlier today, here

Did you have much rain ?
Member Since: Posts: Comments:
LOL!!! So C wins... look at that.
Member Since: Posts: Comments:
910. HadesGodWyvern (Mod)
Philippines Atmospherical Geophysical Astronomical Services and Administration

Tropical Weather Outlook
=======================
At 2:00 AM PhST, a Low Pressure Area was estimated based on satellite and surface data at 330 km West of Central Luzon (14.9°N, 116.9°E).



Another Low Pressure Area (95W) was estimated at 550 km East of Visayas (12.8°N, 131.1°E).
Member Since: May 24, 2006 Posts: 51 Comments: 45307
Quoting StormFreakyisher:
Anyone else getting these severe storms in Palm Beach county?


Yes. I live near Lake Worth/Palm Springs.
Member Since: Posts: Comments:
looks like the nhc wants to eliminate ex97L but is going to wait to see if it refires with dmax tonight
Member Since: Posts: Comments:
DING DING DING C is the winnerrrrr

so, ahem, what is the prize?
Member Since: Posts: Comments:
906. afj3
Looks like those who voted "C" won!
Member Since: Posts: Comments:
Quoting Weather456:
Earlier today, here



Brings back memories when I used to live down in PR... hehe. Definitely you had a nice breeze. :)
Member Since: Posts: Comments:
the verdict all who said two yellows wins
Member Since: Posts: Comments:
Anyone else getting these severe storms in Palm Beach county?
Member Since: May 16, 2009 Posts: 0 Comments: 684
000
ABNT20 KNHC 182329
TWOAT
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
800 PM EDT SAT JUL 18 2009

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

A TROPICAL WAVE OVER THE EASTERN CARIBBEAN SEA IS PRODUCING
SHOWERS AND THUNDERSTORMS AS IT INTERACTS WITH AN UPPER-LEVEL
TROUGH. WHILE RAINFALL ASSOCIATED WITH THE WAVE MAY BE
LOCALLY HEAVY AT TIMES...UPPER-LEVEL WINDS ARE NOT CURRENTLY
CONDUCIVE FOR SIGNIFICANT DEVELOPMENT OF THE SYSTEM AS IT MOVES
WEST-NORTHWESTWARD AT AROUND 15 MPH. THERE IS A LOW CHANCE...LESS
THAN 30 PERCENT...OF THIS SYSTEM BECOMING A TROPICAL CYCLONE DURING
THE NEXT 48 HOURS.

SHOWER ACTIVITY ASSOCIATED WITH A TROPICAL WAVE LOCATED ABOUT
950 MILES EAST OF THE WINDWARD ISLANDS HAS DIMINISHED. THERE IS A
LOW CHANCE...LESS THAN 30 PERCENT...OF THIS SYSTEM BECOMING A
TROPICAL CYCLONE DURING THE NEXT 48 HOURS.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.

$$
FORECASTER BEVEN
Member Since: Posts: Comments:
A TROPICAL WAVE OVER THE EASTERN CARIBBEAN SEA IS PRODUCING
SHOWERS AND THUNDERSTORMS AS IT INTERACTS WITH AN UPPER-LEVEL
TROUGH. WHILE RAINFALL ASSOCIATED WITH THE WAVE MAY BE
LOCALLY HEAVY AT TIMES...UPPER-LEVEL WINDS ARE NOT CURRENTLY
CONDUCIVE FOR SIGNIFICANT DEVELOPMENT OF THE SYSTEM AS IT MOVES
WEST-NORTHWESTWARD AT AROUND 15 MPH. THERE IS A LOW CHANCE...LESS
THAN 30 PERCENT...OF THIS SYSTEM BECOMING A TROPICAL CYCLONE DURING
THE NEXT 48 HOURS.

SHOWER ACTIVITY ASSOCIATED WITH A TROPICAL WAVE LOCATED ABOUT
950 MILES EAST OF THE WINDWARD ISLANDS HAS DIMINISHED. THERE IS A
LOW CHANCE...LESS THAN 30 PERCENT...OF THIS SYSTEM BECOMING A
TROPICAL CYCLONE DURING THE NEXT 48 HOURS.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.

$$
FORECASTER BEVEN


Member Since: May 16, 2009 Posts: 1 Comments: 1231
well looks like a c
Member Since: Posts: Comments:

Viewing: 950 - 900

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.