African Tropical Wave 98L Moving Over Cooler Waters

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

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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

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2578. LargoFl
Tropical Storm DORIAN
As of 12:00 UTC Jul 24, 2013:

Location: 14.0°N 29.0°W
Maximum Winds: 45 kt Gusts: 55 kt
Minimum Central Pressure: 1002 mb
Environmental Pressure: 1012 mb
Radius of Circulation: 150 NM
Radius of Maximum Wind: 20 NM
Eye Diameter: N/A
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Quoting 2498. boltdwright:


Yes, and the thing we are referring to comes from the NHC. The NHC has clearly labeled this Dorian.
Link
Wow. It may be named in a software tool but it doesn't make it official. The data may be accurate, but the people at the NHC are the ones that make the official announcement to the public. That is what I am referring to.
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07/24/2013 Daily Update - GOES East Infrared Hurricane Sector Animation

Features music by Jeff Lynne from his new album "Mr. Blue Sky - The Very Best of ELO"


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2575. KEEPEROFTHEGATE (Mod)
Quoting 2555. SLU:
Dorian starting to wrap its spiral bands now. 50mph might be a little conservative.

and the one over Africa is getting a cyclonic turning going as well we may be going into launch mode here


hmmmmm
Member Since: July 15, 2006 Posts: 168 Comments: 53285
2574. SLU
Quoting 2563. GTstormChaserCaleb:
Eye or dry spot? I guess we will find out in the 11am advisory.


Well I'll tread carefully and call it an eye-like feature until we get a good microwave pass.
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2573. 7544
Quoting 2569. SPLbeater:
Im thinking 40mph at 11AM.

My two cents.


looks like 50 mph at 11 am to me place your bets ;lol i said it first
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Quoting 2567. rmbjoe1954:


I well say one thing. The unspeakable truth is there is no assurance the levees will hold if a heavy soaking hurricane were to impact Lake O. I cringe when I take Rt 441 to Okeechobee City and look at the sloping levees. Triple YIKES!!!


At current levels they are now doing weekly inspections though I don't have confidence they would have time to fix issues should they find them. Unfortunately, they will have to get to a much lower level should there be a serious threat.

Satch
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Any word of doc putting up a new blog post
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Quoting 2567. rmbjoe1954:


I well say one thing. The unspeakable truth is there is no assurance the levees will hold if a heavy soaking hurricane were to impact Lake O. I cringe when I take Rt 441 to Okeechobee City and look at the sloping levees. Triple YIKES!!!


What happens if the levees break? Which might be a good possibility this year.
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Im thinking 40mph at 11AM.

My two cents.
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At day 5 won't this be in Herbert's Box?
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Quoting 2554. HoraceDebussyJones:


Not a good scenario with Lake Okeechobee already at 15.5 ft. level. They have already taken enough water out of lake to poison two main estuaries---just a threat will cause them to release a lot of water and damage ecosystem further. Unfortunately, if not this one, set up does not look good for South Florida in 2013!


I well say one thing. The unspeakable truth is there is no assurance the levees will hold if a heavy soaking hurricane were to impact Lake O. I cringe when I take Rt 441 to Okeechobee City and look at the sloping levees. Triple YIKES!!!
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Quoting 2555. SLU:
Dorian starting to wrap its spiral bands now. 50mph might be a little conservative.

Is that a eye I see poking through?..

Wunderkidcayman I want you to delete that comment..
Member Since: August 14, 2010 Posts: 10 Comments: 16327
Quoting 2543. washingtonian115:
So yout think this could be like Chantal part two?.

yeah it could but getting to my point it is still too far out and anything can happen even the most odd of things

Member Since: June 13, 2009 Posts: 2 Comments: 10852
Quoting 2557. GTstormChaserCaleb:
You want all kinds of weather? Come down to Florida where you get Sun, Rain, T-Storms, Tornadoes, Hurricanes, & Snow.


And strobe like lightening!
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Quoting 2555. SLU:
Dorian starting to wrap its spiral bands now. 50mph might be a little conservative.

Eye or dry spot? I guess we will find out in the 11am advisory.
Member Since: June 30, 2013 Posts: 11 Comments: 7367
Dorian, like the fruit? that's an interesting name
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2561. Relix
Getting near the 15N line. I expect 150+ miles North of PR with minimal impact for us here. I see it pretty hard for it to hit us especially since it seems to be getting stronger. Not worried at the moment but definitely keeping an eye. This "negativism" has bit me in the place with no sun before... Irene and Earl getting very close are one example.
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Quoting 2551. SFLWeatherman:
At that time the NWS was saying a Cat 5 for S FL!


I remember well! Thought we were getting slammed by a cat 4. Was actually scared that time.
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This made me laugh while looking up other hurricane images
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Quoting 2533. Skyepony:
Fresh ASCAT showing some struggle..Lastnight this was slightly tigher with hardly no convection..



That maybe very misleading. It has only tighten up significantly since last night and satellite imagery showing some spiral banding on the south and east sides. The more detailed ASCAT pass earlier suggest tighter strengthening circulation. Regardless its now 50 mph.
Member Since: May 25, 2012 Posts: 0 Comments: 2043
You want all kinds of weather? Come down to Florida where you get Sun, Rain, T-Storms, Tornadoes, Hurricanes, & Snow.
Member Since: June 30, 2013 Posts: 11 Comments: 7367
12z NAM really wraps up our GA disturbance south of Nantucket, MA perhaps hybrid in nature, not fully tropical or non tropical.
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2555. SLU
Dorian starting to wrap its spiral bands now. 50mph might be a little conservative.

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Quoting 2542. boltdwright:


I would love for it to cross Florida and go into the Gulf. I need surf desperately!


Not a good scenario with Lake Okeechobee already at 15.5 ft. level. They have already taken enough water out of lake to poison two main estuaries---just a threat will cause them to release a lot of water and damage ecosystem further. Unfortunately, if not this one, set up does not look good for South Florida in 2013!
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Quoting 2531. GeorgiaStormz:
A straight NE jog and forming an eye.....and u.o.e.n.o it





ok maybe I'm just joking...

Yeah well it's going nowhere to the north fast with that high.
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2552. LargoFl
I guess its time we in florida wake up and take notice huh..in some way this storm will affect us huh..and if it Does cross florida whew..with our rain soaked soils and full lakes and stream..we do NOT need this right now
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At that time the NWS was saying a Cat 5 for S FL!
Quoting 2530. opal92nwf:
Remember how alarming Ike was for South Florida at one time?

Now the question is, will Dorian end up more North or South of it's forecasted track?
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Dorian is official via NHC's Twitter feed.
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Quoting 2531. GeorgiaStormz:
A straight NE jog and forming an eye.....and u.o.e.n.o it





ok maybe I'm just joking...

looking at the atlantic loop zoomed up on the storm that is actually I guess if you want to call it this "mid level eye" it is partially attached to the LLCOC but anyway on the loop it is collapsing and shift Westward instead of WNW like before
Member Since: June 13, 2009 Posts: 2 Comments: 10852
2548. hydrus
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Quoting 2519. washingtonian115:
Talk about false advertising.lol


This one is better suited..

That top pictures is unreal. Coconut palms cannot survive in any location on the border between Florida and Alabama. They really are not able survive outside zone 10B, and the farthest north I've personally seen them is in the Melbourne/Cocoa Beach area near the coast.
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Quoting 2519. washingtonian115:
Talk about false advertising.lol


This one is better suited..
Forgot this one :D

Member Since: June 30, 2013 Posts: 11 Comments: 7367
Quoting 2517. FOREX:


Some bloggers are talking about a strenghthening Bermuda high while others are showing recurve cones of Earl. Confusing to me.


Its the blog yoyo -- expect it to
swing a few thousand times before it lands!
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Quoting 2527. wunderkidcayman:

yeah anyway huh Wash do you understand the point I'm making
So yout think this could be like Chantal part two?.
Member Since: August 14, 2010 Posts: 10 Comments: 16327
Quoting 2532. CaneHunter031472:
This is the scenario I've been putting on the table since about two weeks already. The Bermuda High is very strong this year and well into texas. Cape verdes will not find a way to turn north before getting dangerously close to the US. I see one of two scenarios happening here. Either it makes landfall on the East Coast or it crosses Florida and makes it into the Gulf. Whichever the case unfortunately for what I see I am concern about landfall, but as with everything in Nature there can be surprises, and it is still too far east for us to make any educated guesses. Nevertheless it is something worth watching.


I would love for it to cross Florida and go into the Gulf. I need surf desperately!
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2541. KEEPEROFTHEGATE (Mod)
04L/TS/D/CX
Member Since: July 15, 2006 Posts: 168 Comments: 53285
2540. 7544
Quoting 2373. congaline:
Wow! Look at Dorian! Looking goooood!


looks like its getting the S shape to it we all know what that means still a long way away tho
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ATCF classification of Dorian as a "straight shooter".

DORIAN, AL, L, , , , , 04, 2013, TS, S,

4.1 DESCRIPTIVE DATA

Note: Track type is a subjective classification of the storm as a straight mover, recurver, or odd mover. A straight storm path is one which maintained a somewhat constant heading between 250o - 360o. A storm is considered a recurver if it turned from an initial path toward the west or northwest to a path toward the northeast. An odd moving storm, therefore, is one which did not fit in the other two categories or contained loops in the track.
Member Since: September 23, 2005 Posts: 14 Comments: 10839
Well got to head out now, but I guess when I get back we will have TS Dorian....
You all play nice and I'll be back in a little while

Have a Great Day
Taco :o)
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2537. dabirds
Quoting 2485. SouthernIllinois:

Bet you really miss OLTL now since it's been off the air for two years. We're you a AMC fan too?
They were, would leave on after AMC, saw it while making lunch, had no class on Fri. one semester.

Had asked Fri., think you'd already signed off though, which lake is the Cove on? No luck googling.
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Quoting 2529. mikatnight:


No kidding! We walked Dex up that way upon occasion. Boynton is nice too. Yep, just down the street from the Keylime. I'd like to talk the owner into putting a PWS there.

BTW, there's no rule against having a PWS located at a business, is there?


I love the old Key Lime! I love Kona Bay more though =)
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.
Member Since: June 30, 2013 Posts: 11 Comments: 7367
Quoting 2526. Bluestorm5:
Dorian is amazing... haven't shown any hint of weakening even though it should be over cooler waters today and tomorrow. After that... I honestly believe Dorian could have a shot to become significant storm.



26C is right around the threshold for TS I think It has a great chance of holding itself together. Conditions has changed from when we were on the blog last nite.
Member Since: May 25, 2012 Posts: 0 Comments: 2043
2533. Skyepony (Mod)
Fresh ASCAT showing some struggle..Lastnight this was slightly tigher with hardly no convection..

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This is the scenario I've been putting on the table since about two weeks already. The Bermuda High is very strong this year and well into texas. Cape verdes will not find a way to turn north before getting dangerously close to the US. I see one of two scenarios happening here. Either it makes landfall on the East Coast or it crosses Florida and makes it into the Gulf. Whichever the case unfortunately for what I see I am concern about landfall, but as with everything in Nature there can be surprises, and it is still too far east for us to make any educated guesses. Nevertheless it is something worth watching.
Member Since: Posts: Comments:
A straight NE jog and forming an eye.....and u.o.e.n.o it





ok maybe I'm just joking...
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Remember how alarming Ike was for South Florida at one time?

Now the question is, will Dorian end up more North or South of it's forecasted track?
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Quoting 2501. PalmBeachWeather:
Mik...Judging by the photo I would say you are around the corner from the Old Key Lime House (bridge construction) I lived up the road from you until 2 months ago on South Palmway, lake Worth... I now live in West Boynton


No kidding! We walked Dex up that way upon occasion. Boynton is nice too. Yep, just down the street from the Keylime. I'd like to talk the owner into putting a PWS there.

BTW, there's no rule against having a PWS located at a business, is there?
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Quoting 2509. opal92nwf:
Kinda looks like an eye


It has lost weight since it emerge off Africa. Allowing it to deepen even with sst not supporting it. It still has a piece of energy to its east and south that will continually feed our system through those cool waters. After that it should really bulk up some and wrap that energy around it.
Member Since: May 25, 2012 Posts: 0 Comments: 2043

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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.