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: 2678 - 2628

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 2673. NYtampagirl:


How about New Jersey being called "the Garden State"? The pollution there will kill your lungs in about three seconds! the only thing that grows in NJ is toxic waste! And rude people.


You need to get off the Turnpike honey to see the real Jersey
Member Since: Posts: Comments:
2677. Grothar
Why are they late with the advisories?
Member Since: Posts: Comments:
Quoting 2614. LargoFl:
GFS really wants dorian going into the gulf..thats bad news

If it goes any farther south it could be another Hispaniola dilemma....
Member Since: Posts: Comments:
2675. hydrus
Quoting 2568. SecretStormNerd:
At day 5 won't this be in Herbert's Box?
Too far out to say with certainty.
Member Since: September 27, 2007 Posts: 1 Comments: 21184
2674. Dakster
Quoting 2666. Grothar:


Yes.


That explains why the high is building back in.
Member Since: Posts: Comments:
Quoting 2519. washingtonian115:
Talk about false advertising.lol


This one is better suited..


How about New Jersey being called "the Garden State"? The pollution there will kill your lungs in about three seconds! the only thing that grows in NJ is toxic waste! And rude people.
Member Since: Posts: Comments:
2672. LargoFl
Dorian is coming into view now
Member Since: Posts: Comments:
NWS have it going back down to 45 MPH?
Member Since: Posts: Comments:
2670. Mclem1
:::Knows better than to post anything witty or important on a blog that is sure to be updated in mere moments...:::
Member Since: Posts: Comments:
Quoting 2647. Grothar:
The high is expected to build back in making Dorian move in a more westerly direction after it reaches near the Northern Antilles. There is still the possibilty of the high retreating slightly in a few day.s


The high will be a big problem this year because of it's intensity. I don't see many fish storms (if any) happening. I wonder if there is any similarity between this year's High and 2005.
Member Since: Posts: Comments:
Quoting 2659. wunderkidcayman:


waiting for new satellite data to confirm
Confirm what?
Member Since: June 30, 2013 Posts: 12 Comments: 8225
Quoting 2653. Bluestorm5:
Sanford, right? You shouldn't worry about any storm unless we got Category 4 or 5 into Myrtle Beach.


I didnt say I was worried about it, because I caint change what happens. Irene was a cat 1(a large one) and we had gusty winds...and if we get another inch or few inches of rain, along with gusty winds, these oak trees will come down like dominoes. Prices also go up, so dont say inland areas aint affected.
Member Since: Posts: Comments:
2666. Grothar
Quoting 2651. Dakster:


Is there a lot of THC in the area?


Yes.
Member Since: Posts: Comments:
Quoting 2630. washingtonian115:
Karen is being reincarnated into all these waves and is waiting for the right one to come and pay a visit to the NHC...


Fixed it for ya.
Member Since: Posts: Comments:
jump up to 50 mph
Member Since: Posts: Comments:
Quoting 2654. washingtonian115:
Shows him getting to 60mph.NHC didn't expect this burst of intensification and neither did I.

Now it seems the doubt whether it will survive the cooler SSts and stable air is gone by the NHC in these 48 hours.
Member Since: Posts: Comments:
98L when I went to bed, 50mph Dorian when I wake up. This season sure is something.
Member Since: Posts: Comments:
50 mph now!
Member Since: Posts: Comments:
Quoting 2639. GTstormChaserCaleb:
4/0/0
Tropical Storm Dorian
...FOURTH NAMED STORM OF THE 2013 SEASON FORMS...
11:00 AM EDT Wed Jul 24
Location: 14.3°N 29.9°W
Moving: WNW at 21 mph
Min pressure: 1002 mb
Max sustained: 50 mph


waiting for new satellite data to confirm
Member Since: June 13, 2009 Posts: 2 Comments: 11977
Portlight Honored with 1 WTC Flag

Chairman Paul Timmons and New Jersey Portlight Volunteers received a Letter of Appreciation and a Flag that flew over the New WTC 1 in New York Monday morning as a token of their State's appreciation of the work done Post Sandy by Portlight and it's volunteers.
Member Since: Posts: Comments:
Member Since: June 30, 2013 Posts: 12 Comments: 8225
Quoting 2648. Bluestorm5:
Kevin Durant like to have weather patterns on his shoes. Pretty neat.

Quoting 2648. Bluestorm5:
Kevin Durant like to have weather patterns on his shoes. Pretty neat.



These were his original ones, but all the one's I see are almost $1000 now




anyway back on topic.
Member Since: Posts: Comments:
Quoting 2634. GeorgiaStormz:
BUY ME THESE SHOES!!!!!!



lol, really?
Member Since: Posts: Comments:
Shows him getting to 60mph.NHC didn't expect this burst of intensification and neither did I.
Member Since: Posts: Comments:
Quoting 2643. SPLbeater:


Bout 115 miles. Yup.
Sanford, right? You shouldn't worry about any storm unless we got Category 4 or 5 into Myrtle Beach.
Member Since: August 1, 2011 Posts: 28 Comments: 8007
As I mentioned earlier in this blog, it is high time a team of mets, storm chasers, video producers and mariners take to the sea and start tracking these storms while they are still well out at sea...and LIVE BROADCAST as they follow the storm.

It would have been AWESOME to see Dorian ramp up this morning from a wave to a tropical storm.
Member Since: Posts: Comments:
2651. Dakster
Quoting 2647. Grothar:
The high is expected to build back in making Dorian move in a more westerly direction after it reaches near the Northern Antilles. There is still the possibilty of the high retreating slightly in a few day.s


Is there a lot of THC in the area?
Member Since: Posts: Comments:
No hurricane yet... on the 5 day end

Member Since: Posts: Comments:
Quoting 2620. washingtonian115:
The one where you said i was a big fool...

ok but before I do let me clear this up I did not say I made you a fool I said by what you said is making you sound like a fool now I know your not really a fool but by the thing you say it makes you sound like one for example what you said that I had mad that response to
anyway ok I'll kill that comment now
Member Since: June 13, 2009 Posts: 2 Comments: 11977
Quoting 2634. GeorgiaStormz:
BUY ME THESE SHOES!!!!!!

Kevin Durant like to have weather patterns on his shoes. Pretty neat.

Member Since: August 1, 2011 Posts: 28 Comments: 8007
2647. Grothar
The high is expected to build back in making Dorian move in a more westerly direction after it reaches near the Northern Antilles. There is still the possibilty of the high retreating slightly in a few day.s
Member Since: Posts: Comments:
2646. StormWx
A break in the ridge would be great, and allow Dorian to recurve out to sea. Some of the ensemble runs are showing this.
Member Since: Posts: Comments:
Quoting 2639. GTstormChaserCaleb:
4/0/0
Tropical Storm Dorian
...FOURTH NAMED STORM OF THE 2013 SEASON FORMS...
11:00 AM EDT Wed Jul 24
Location: 14.3°N 29.9°W
Moving: WNW at 21 mph
Min pressure: 1002 mb
Max sustained: 50 mph


beat me to it.
Member Since: Posts: Comments:
2644. Dakster
Remember that NHC intensity forecasts are off by as much as 2 categories either way.
Member Since: Posts: Comments:
Quoting 2637. Bluestorm5:
You're inland, right...


Bout 115 miles. Yup.
Member Since: Posts: Comments:
...FOURTH NAMED STORM OF THE 2013 SEASON FORMS...

11:00 AM EDT Wed Jul 24
Location: 14.3°N 29.9°W
Moving: WNW at 21 mph
Min pressure: 1002 mb
Max sustained: 50 mph
Member Since: Posts: Comments:
2641. KEEPEROFTHEGATE (Mod)



remember wind speeds are shown in KM PER HOUR
Member Since: Posts: Comments:
2640. tkeith
Quoting Hurricanes305:


Yea I know! a lot of changed in 5 hours. Itching to see the new cone.
and a new blog by the doc...
Member Since: Posts: Comments:
4/0/0
Tropical Storm Dorian
...FOURTH NAMED STORM OF THE 2013 SEASON FORMS...
11:00 AM EDT Wed Jul 24
Location: 14.3°N 29.9°W
Moving: WNW at 21 mph
Min pressure: 1002 mb
Max sustained: 50 mph
Member Since: June 30, 2013 Posts: 12 Comments: 8225
Quoting 2623. hurricanes2018:
this went to 35 mph to 50 mph in five hours!! wow!! now its a tropical storm with winds 50 mph that fast


Yea I know! a lot of changed in 5 hours. Itching to see the new cone.
Member Since: Posts: Comments:
Quoting 2632. SPLbeater:


The ensemble coming close to the NC coast is too close for comfort! Another couple hundred miles would be quite alright..
You're inland...
Member Since: August 1, 2011 Posts: 28 Comments: 8007
2636. LargoFl
Member Since: Posts: Comments:
2635. hydrus
Quoting 2603. Grothar:


10 to 1 says you could get in trouble for betting on here.
I joked about it a while ago..I had to..It was funny with all the bantering going on about Chantal...Good morning Gro.
Member Since: September 27, 2007 Posts: 1 Comments: 21184
BUY ME THESE SHOES!!!!!!

Member Since: Posts: Comments:
Quoting 2617. MonsterTrough:
During Chantal NOAA Hurricane Hunters were sent to the islands as a 'forward base'. I understand Dorian is only an hour old, any idea when or if they may be deployed again? Pat, any thoughts?
I think storm got to be past 55 W, I believe.
Member Since: August 1, 2011 Posts: 28 Comments: 8007
Quoting 2625. unknowncomic:
11AM Ensemble shows recurves.



The ensemble coming close to the NC coast is too close for comfort! Another couple hundred miles would be quite alright..
Member Since: Posts: Comments:
2631. Mclem1
Quoting 2614. LargoFl:
GFS really wants dorian going into the gulf..thats bad news

If there's one thing I know about the GFS is that it tends to be a pathological liar.

...See what I did there?
Member Since: Posts: Comments:
92L is being reincarnated into all these waves and is waiting for the right one to come and pay a visit to the NHC...
Member Since: Posts: Comments:
Quoting 2570. SecretStormNerd:


What happens if the levees break? Which might be a good possibility this year.


evacuation plans for those south of Okeechobee Lake are being discussed.. but, unfortunately, not by those who have the power to order it.

a quote from one of my friends;

The wet season is not very significant anymore as the dry season now has been very wet too.

The greatest significance is when will areas around Lake Okeechobee be evacuated -- that is not specified in any of the emergency plans or anywhere that I have seen.

From the engineering analysis done years ago (after the Bromwell review) evacuation would be required at 17.5 feet, for sure.

My gut feeling is by 16.5 feet, an emergency would be declared. /quote
Member Since: Posts: Comments:
2628. tkeith
2617. MonsterTrough 9:47 AM CDT on July 24, 2013

Not positive but I think 55W is the threshhold
Member Since: Posts: Comments:

Viewing: 2678 - 2628

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.