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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2628. tkeith
2617. MonsterTrough 9:47 AM CDT on July 24, 2013

Not positive but I think 55W is the threshhold
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Quoting 2603. Grothar:


10 to 1 says you could get in trouble for betting on here.


oh I bet
Member Since: June 17, 2011 Posts: 11 Comments: 6539
NHC issuing advisories on TS DORIAN
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11AM Ensemble shows recurves.

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new satellite floater images should be coming in 30 mins time
Member Since: June 13, 2009 Posts: 2 Comments: 12164
this went to 35 mph to 50 mph in five hours!! wow!! now its a tropical storm with winds 50 mph that fast
Member Since: March 12, 2013 Posts: 27 Comments: 53939

Quoting 2604. CarolinaHurricanes87:
For how much dry air is close by, the outflow on Dorian is looking pretty impressive.



I say its trying to wrap the piece of energy on the southern side.



That image is unsettling as the MJO comes back and limited SAL the next storm after Dorian may blow up.
Member Since: May 25, 2012 Posts: 0 Comments: 2043
3 tropical storms have formed south of 23.5 N before august, a rare occurrence indeed... speaks volumes for the atmospheric conditions compared to normal, interesting year ahead!
Member Since: June 17, 2011 Posts: 11 Comments: 6539
Quoting 2608. wunderkidcayman:

which one is that now

The one where you said i was a big fool...
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Current conditions Down Town Miami
Link
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2618. tkeith
Quoting Grothar:


10 to 1 says you could get in trouble for betting on here.
I'll take those odds :)
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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?
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2616. Dakster
Quoting 2603. Grothar:


10 to 1 says you could get in trouble for betting on here.


I'll take that bet.
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2615. VR46L
Gosh Was it 2010 had Julia and Igor at the same time

looky looky

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2614. LargoFl
GFS really wants dorian going into the gulf..thats bad news
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I told S.Florida they needed to watch out for a T.C rather that be Dorian or some other one.But they have been very wet later and wet patterns can lead to bigger problems down the road.
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2611. hydrus
Quoting 2575. KEEPEROFTHEGATE:
and the one over Africa is getting a cyclonic turning going as well we may be going into launch mode here


hmmmmm
HWRF had that as a potent system Yesterday..Not so much today..I believe that will change tho..



Member Since: September 27, 2007 Posts: 1 Comments: 21432
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!!!


I lived in Okeechobee for many years. One of my homes sat right across the rim canal from the dike. It always was in my thoughts as storms approached us. However I don't ever recall the lake being full in the years I lived there. We shall have to wait to see where this storm goes. It's way to early to get concerned, just be aware of it. Of course I'm in Colorado right now so it's not an issue here!
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Da latest model runs:





Member Since: June 30, 2013 Posts: 12 Comments: 8456
Quoting 2566. washingtonian115:
Is that a eye I see poking through?..

Wunderkidcayman I want you to delete that comment..

which one is that now

Member Since: June 13, 2009 Posts: 2 Comments: 12164
2607. KEEPEROFTHEGATE (Mod)
forward speed 18KT needs to slow to about 13 14 KT
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Quoting 2585. Bluestorm5:
Likely, but it could go north of it. I'm not a big believer in Herbert's Box as storms had hit Florida even though it missed the box or storms not hitting Florida even though it went through the box.


Yes, that is true. It's ok, I bought a bunch of crayons to light when the power goes out lol and a new tent for the kids.
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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!


another thing is we don't need a hurricane in the GOM with all the rain we have had lately all our trees will be up rooted. About like When George came thru I lost my Apple trees and other fruit trees because the soil is so wet, they just fall over.

sheri
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For how much dry air is close by, the outflow on Dorian is looking pretty impressive.
Member Since: August 4, 2011 Posts: 0 Comments: 631
2603. Grothar
Quoting 2573. 7544:


looks like 50 mph at 11 am to me place your bets ;lol i said it first


10 to 1 says you could get in trouble for betting on here.
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Quoting 2589. whitewabit:


Aren't they releasing large amounts of water into both rivers out of "O"


Have been for weeks----estuaries already have had way too much fresh water pumped in. Quite a bad situation.
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2601. SLU
FORECAST VALID 25/0000Z 15.0N 32.6W
MAX WIND 50 KT...GUSTS 60 KT.
50 KT... 20NE 0SE 0SW 20NW.
34 KT... 50NE 40SE 30SW 40NW.
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Quoting 2575. KEEPEROFTHEGATE:
and the one over Africa is getting a cyclonic turning going as well we may be going into launch mode here


hmmmmm
Been saying for a while MJO coming back to the Atlantic by August will support a vigorous TW that comes off Africa. Atlantic is about to turn on the switch.
Member Since: May 25, 2012 Posts: 0 Comments: 2043
Quoting KEEPEROFTHEGATE:
and the one over Africa is getting a cyclonic turning going as well we may be going into launch mode here


hmmmmm


Yeah, that could very well become Erin... We are go for launch for the 2013 Hurricane season. Strap yourselves in and hold on tight, it's going to be a bumpy ride. I have everyone over there in my prayers. Good luck and I'll see everyone intact on the other size, Just keep your head down and be prepared.
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2598. SLU
TROPICAL STORM CENTER LOCATED NEAR 14.3N 29.9W AT 24/1500Z
POSITION ACCURATE WITHIN 20 NM

PRESENT MOVEMENT TOWARD THE WEST-NORTHWEST OR 285 DEGREES AT 18 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 1002 MB
MAX SUSTAINED WINDS 45 KT WITH GUSTS TO 55 KT.
34 KT....... 40NE 30SE 0SW 30NW.
12 FT SEAS.. 45NE 30SE 0SW 30NW.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.
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2597. FOREX
Quoting 2588. SLU:


The Cape Verde season is open for business.


Taz makes that call.
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Quoting 2557. GTstormChaserCaleb:
You want all kinds of weather? Come down to Florida where you get Sun, Rain, T-Storms, Tornadoes, Hurricanes, & Snow.


this is what we really get;



and the new storm will just make things worse.
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Quoting 2555. SLU:
Dorian starting to wrap its spiral bands now. 50mph might be a little conservative.

I see the bands to the south haven't wrapped around yet... some of us thought it would do it overnight.
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2594. Grothar
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I imagine Dr M is waiting for full advisory from NHC.
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Quoting 2584. fireflymom:
Do we know the forward speed of  Dorian yet?


WNW at 18 knots...moving pretty good to me.
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2591. KEEPEROFTHEGATE (Mod)
Quoting 2571. JTDailyUpdate:
Any word of doc putting up a new post
soon waiting on the NHC
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2590. FOREX
Quoting 2573. 7544:


looks like 50 mph at 11 am to me place your bets ;lol


50
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2589. whitewabit (Mod)
Quoting 2572. HoraceDebussyJones:


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


Aren't they releasing large amounts of water into both rivers out of "O"
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2588. SLU
Quoting 2575. KEEPEROFTHEGATE:
and the one over Africa is getting a cyclonic turning going as well we may be going into launch mode here


hmmmmm


The Cape Verde season is open for business.
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Dorian is amazing storm lets hope is not going to hit the hot water next to the east coast
Member Since: March 12, 2013 Posts: 27 Comments: 53939
NHC site just confirmed TS Dorian. BUT they have not updated the info yet. Should come with the in 15 minutes.
Member Since: May 25, 2012 Posts: 0 Comments: 2043
Quoting 2568. SecretStormNerd:
At day 5 won't this be in Herbert's Box?
Likely, but it could go north of it. I'm not a big believer in Herbert's Box as storms had hit Florida even though it missed the box or storms not hitting Florida even though it went through the box.
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Do we know the forward speed of  Dorian yet?
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Quoting 2570. SecretStormNerd:


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


Look back to 1928!
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I was VERY conservative I see..

000
WTNT24 KNHC 241425
TCMAT4

TROPICAL STORM DORIAN FORECAST/ADVISORY NUMBER 2
NWS NATIONAL HURRICANE CENTER MIAMI FL AL042013
1500 UTC WED JUL 24 2013

THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.

TROPICAL STORM CENTER LOCATED NEAR 14.3N 29.9W AT 24/1500Z
POSITION ACCURATE WITHIN 20 NM

PRESENT MOVEMENT TOWARD THE WEST-NORTHWEST OR 285 DEGREES AT 18 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 1002 MB
MAX SUSTAINED WINDS 45 KT WITH GUSTS TO 55 KT.
34 KT....... 40NE 30SE 0SW 30NW.
12 FT SEAS.. 45NE 30SE 0SW 30NW.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.

REPEAT...CENTER LOCATED NEAR 14.3N 29.9W AT 24/1500Z
AT 24/1200Z CENTER WAS LOCATED NEAR 14.0N 29.0W
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Quoting 2519. washingtonian115:
Talk about false advertising.lol


This one is better suited..
91.5 million visitors last year.
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Official... NHC Twitter. "Tropical Storm Dorian advisory 2 issued. Fourth named storm of the 2013 season forms.
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2579. SLU
Quoting 2566. washingtonian115:
Is that a eye I see poking through?..

Wunderkidcayman I want you to delete that comment..


If it is still there by 18z then it's probably an eye....
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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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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.