African Tropical Wave 98L Moving Over Cooler Waters

By: Dr. Jeff Masters , 2:23 PM GMT on July 23, 2013

Share this Blog
49
+

A strong and well-organized tropical wave that moved off the coast of Africa on Monday (98L) is located a few hundred miles south of the Cape Verde Islands and is moving west-northwest at 15 - 20 mph. Satellite images show that 98L has a decent amount of spin, but only a modest amount of heavy thunderstorms that have not changed much in intensity or areal coverage this morning. The wave is under a moderate 10 - 20 knots of wind shear, which will tend to allow slow development. A large amount of dry air lies to the north and west of 98L, and this dry air will likely interfere with development later this week. The SHIPS model predicts that wind shear will stay in the moderate range through Saturday. Ocean temperatures are barely adequate for development, about 26.5°C today, and will be below average over the region of ocean 98L will be traversing on Wednesday and Thursday, 25 - 26°C. These temperatures are very marginal for development. The Madden Julian Oscillation (MJO), a pattern of increased thunderstorm activity near the Equator that moves around the globe in 30 - 60 days, does not favor increased chances of Atlantic tropical cyclone formation this week. The reliable computer models for tropical cyclone genesis do not predict that 98L will develop this week. In their 8 am EDT Tuesday Tropical Weather Outlook, NHC gave 98L a 40% chance of developing into a tropical cyclone by Thursday. 98L should maintain a west-northwest track through the week, and may spread heavy rains and gusty winds to the northern Lesser Antilles Islands beginning on Saturday night or on Sunday.


Figure 1. Satellite image of 98L off the coast of Africa taken at 8 am EDT Tuesday July 23, 2013, with a satellite analysis of where dry air is, as well. A large amount of dry air lies to the north and west of 98L, and will likely interfere with development later this week. Image credit: University of Wisconsin CIMSS and NOAA/HRD.

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: 2178 - 2128

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 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | 56 | 57Blog Index

Quoting 2176. LargoFl:
is that an eye trying to form?...........


Lol it's just wrapping up a bit

Gotta love it though!
Member Since: Posts: Comments:

Quoting 2162. Grothar:
I see all the models are pretty consistent with this moving WNW north of the islands.

http://i.imgur.com/Oc8h81z.gif
Hey Gro, the long nights are ahead of us. Good old hurricane season.But that slight WNW track north of the islands is very interesting as there is a forecast for a big 600 DM High in the next couple of day that is capable of sending a deepening low very close to SE US (Florida up to the Carolinas). just speculating as that is far out still :)
Member Since: May 25, 2012 Posts: 0 Comments: 2043
2176. LargoFl
is that an eye trying to form?...........
Member Since: Posts: Comments:
I think this storm be belong to Florida
Member Since: Posts: Comments:
Quoting 2171. LargoFl:
next monday this blog explodes lol............


It shouldn't be able to recurve until it's too late after that high builds strong...
Member Since: Posts: Comments:
GFS has 98E landfalling in Hawaii...
Member Since: Posts: Comments:
Quoting 2167. washingtonian115:
Says the 30-40 knots of shear in front of it.


Easterly shear will not do that much damage to a storm. southwesterly on the other hand would
Member Since: Posts: Comments:
2171. LargoFl
next monday this blog explodes lol............
Member Since: Posts: Comments:
Quoting 2136. beell:


Thanks for the vote, Gator. And you may be right. That post is probably about three days too early to place treat with a whole lot of confidence. Either way, any issues with SW shear may be short-lived.


Hey beell, how are you this am, people dont realize that upper level winds wont be a big deal unless it starts moving like Chantal did. Trades are quite slower than that as are 6 days till August. Atlantic slowly becoming more favorable as August approaches.




Also sal has diminished exponentially in the last couple of days and no longer a issue that is why the NHC keeps it at TS strength.

Member Since: May 25, 2012 Posts: 0 Comments: 2043
2168. Grothar



Intensities have come up quite a bit

Member Since: July 17, 2009 Posts: 71 Comments: 27208
Quoting 2163. mcluvincane:


Seriously doubt it, this should be upgraded to a TS on next advisory and stay a TS for at least 5 to 6 days. After that, Dorian might be a formidable tropical system somebody will have to deal with IMO
Says the 30-40 knots of shear in front of it.
Member Since: August 14, 2010 Posts: 10 Comments: 17810
2166. LargoFl
Member Since: Posts: Comments:
Quoting 2160. LargoFl:
all eyes on dorian but check out bay of campeche..........
That could be Erin or Fernand,just depend on the wave in Africa.
Member Since: June 11, 2013 Posts: 20 Comments: 3383
Quoting 2143. washingtonian115:
Look how small it is..I mean small storms are fragile to their surrounding environment..It wouldn't surprise me to see this open up as a wave again or get shredded to pieces.The shear is high.


Seriously doubt it, this should be upgraded to a TS on next advisory and stay a TS for at least 5 to 6 days. After that, Dorian might be a formidable tropical system somebody will have to deal with IMO
Member Since: Posts: Comments:
2162. Grothar
I see all the models are pretty consistent with this moving WNW north of the islands.

Member Since: July 17, 2009 Posts: 71 Comments: 27208
Who will do the honours and check the navy ACFT.
Member Since: June 11, 2013 Posts: 20 Comments: 3383
2160. LargoFl
all eyes on dorian but check out bay of campeche..........
Member Since: Posts: Comments:
Quoting 2152. yonzabam:
This itsy bitsy mess o' clouds ain't gonna amount to anything. Cold water, dry air, shear - Dorian's a dead man walking. Waste of a name. Dorian's just being sent on a scouting mission to test the water for the September blitzkreig.


It's not a waiste of a name unless it meets the criteria!
Member Since: Posts: Comments:
2158. GatorWX
"And through the window in the wall
comes streaming in on sunlight wings
A million bright ambassadors of morning"



Have a great day everyone!
Member Since: Posts: Comments:

Quoting 2107. HurricaneAndre:

Getting stronger


Great catch Dre :) our TD4 is getting better defined this morning and convection is looking healthy so this may be Dorian by 11:00am if it does not speed up too fast it will miss the heavy bands of shear that is over the NE Islands past 40W and it at its current pace it wont be over cooler waters for long. It should slow down to under 15mph as it reaches the island and the jet weakens and move north. once it get to 50W gradually strengthen is likely and has a shot of hurricane status the islands, Bahamas, Florida need to watch this closely.
Member Since: May 25, 2012 Posts: 0 Comments: 2043
2156. Relix
Hmm, pretty close to the N coast of PR. Too far away too know but I believe this will be the case of a system being a little farther north than that forecast
Member Since: Posts: Comments:


Looking really good, might be a TS now....

Thunderstorms held strong over night

Lots of shear and cooler waters ahead. Good thing it's not late August with a depression out there and the ridge like it is.
Member Since: Posts: Comments:
Quoting 2151. CycloneOz:


If so, when would be the earliest update for an upgrade?
in a little bit,
Member Since: June 11, 2013 Posts: 20 Comments: 3383
This itsy bitsy mess o' clouds ain't gonna amount to anything. Cold water, dry air, shear - Dorian's a dead man walking. Waste of a name. Dorian's just being sent on a scouting mission to test the water for the September blitzkreig.
Member Since: Posts: Comments:
Quoting 2148. islander101010:
vis looks like a storm now p.e.
What does p.e. mean.
Member Since: June 11, 2013 Posts: 20 Comments: 3383
Quoting 2147. hurricanes2018:
maybe a tropical storm soon
Yep has that look to it.
Member Since: June 11, 2013 Posts: 20 Comments: 3383
vis looks like a storm now p.e. stronger than i ever anticipated
Member Since: Posts: Comments:
maybe a tropical storm soon
Member Since: March 12, 2013 Posts: 110 Comments: 105715
2146. RTLSNK
Quoting 2133. SouthernIllinois:

Morning Snake! :D


Good morning! Blog froze on me for a few minutes and
the quote button wouldn't work. We will be going into
hyper speed any time now! :)
Member Since: Posts: Comments:
Good Morning. I see we have TD4.
Member Since: Posts: Comments:
2144. GatorWX

Member Since: Posts: Comments:
Look how small it is..I mean small storms are fragile to their surrounding environment..It wouldn't surprise me to see this open up as a wave again or get shredded to pieces.The shear is high.
Member Since: August 14, 2010 Posts: 10 Comments: 17810
Weird, modified comment and it created another post instead of changing the original one. Did it again and it work fine!
Member Since: Posts: Comments:
So have things settled down this morning? I haven't taken the time to read back yet but I will a little bit here soon. I logged in last night and it was like troll city, even had to fight off a virus that tried to get on my computer while on this site.

Anyways I see we have a TD this morning. This seems like another one of those storms that may defy the odds and develop despite not so favorable conditions.
Member Since: Posts: Comments:
2140. SLU
The formation of 2 tropical storms this month east of the Caribbean is bad, bad news for anyone who was hoping for a quite Cape Verde season. Every single season since 1950 which featured such development east of 60 west all featured very hectic Cape Verde seasons and most of them had at least one extremely deadly hurricane. This year with the stronger than normal ridge you can expect that if we get a deadly Cape Verde hurricane that it could threaten land.



























Member Since: Posts: Comments:
Come on Navy,let's see an upgrade.
Member Since: June 11, 2013 Posts: 20 Comments: 3383
Member Since: June 11, 2013 Posts: 20 Comments: 3383
2137. LargoFl
Quoting 2134. HurricaneAndre:
Looks what's in the BOC.
yes i saw that..and it will be August
Member Since: Posts: Comments:
2136. beell
Quoting 2127. GatorWX:


I trust your advise as much as anyone's on upper level conditions. I just think its going to struggle quite a bit near the islands.


Thanks for the vote, Gator. And you may be right. That post is probably about three days too early to treat with a whole lot of confidence. Either way, any issues with SW shear may be short-lived.
Member Since: Posts: Comments:
2135. GatorWX
Quoting LargoFl:
yeah I wont leave with anything under a 4 either..even then it would have to be coming in directly at me..im on high ground so i dont worry about surge etc...wind is my only worry...roof comes off your in big trouble huh...


That is certainly the case largo lol. I'll say I'll take wind over water though when it comes down to it.
Member Since: Posts: Comments:
Quoting 2131. LargoFl:
Looks what's in the BOC.
Member Since: June 11, 2013 Posts: 20 Comments: 3383
Member Since: June 11, 2013 Posts: 20 Comments: 3383
2131. LargoFl
Member Since: Posts: Comments:
Member Since: June 11, 2013 Posts: 20 Comments: 3383
Member Since: June 11, 2013 Posts: 20 Comments: 3383
2128. LargoFl
looks like from monday thru thursday he stays by the islands stalled out..maybe he feels the front,looking for a path to take..
Member Since: Posts: Comments:

Viewing: 2178 - 2128

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 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | 56 | 57Blog 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.

Local Weather

Overcast
29 °F
Overcast

JeffMasters's Recent Photos

Lake Effort Snow Shower Over Windsor, Ontario
Sunset on Dunham Lake
Pictured Rocks Sunset
Sunset on Lake Huron