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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2378. will40
Quoting 2360. SecretStormNerd:
At what location does a storm need to be for recon to be sent out?


i think they can go as far as 50W this year
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Quoting 2376. Mikla:
16 Frames, 15 min apart. Click image to see larger version..


RI much?!
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2376. Mikla
16 Frames, 15 min apart. Click image to see larger version..
Member Since: October 13, 2006 Posts: 0 Comments: 305
I need to unwind lol ... DORIAN is stressing me XD XD
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Quoting 2336. Grothar:


Mik, you think we can have a "Dexter Box"?


I "heard" he wants to be a hurricane hunter.. jes sayin' :)

Mik, you and Dexter have WU mail...
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Wow! Look at Dorian! Looking goooood!
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I would hate for this to head to Florida as a hurricane although I think that is highly unlikely..We'll never see the end of them!.
Member Since: August 14, 2010 Posts: 10 Comments: 18733
2371. Patrap
TS Dorian RGB Loop

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2370. Levi32
Quoting 2325. Grothar:
Hey, Levi.

Is this over you?





Yup, woke up to it this morning. I'm going to miss thunderstorms when I leave the south.
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Storm need two be. At 55w
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looks like we are going through a period of RI ....if this keeps up we may see a Hurricane at 5:00
Member Since: September 8, 2010 Posts: 0 Comments: 2247
Figures we finally possibly maybe might get a cane and it is time for my finals. Boo!
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counting on a florida front early august forget about that.
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Quoting 2340. SFLWeatherman:
Wow we may get a Hurricane!


Cool XD
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Quoting 2356. CybrTeddy:


I'll give it credit though for sniffing out the storm from 200+ hours out to about 48 hours out before it dropped it.


I Personally think the GFS nailed it when it was still over Africa. So I will give it credit for that.
Member Since: May 25, 2012 Posts: 0 Comments: 2043
2362. SLU
Quoting 2338. CybrTeddy:


Yes, it has significant implications for our upcoming hurricane season. Not even 2008 had two July CV storms. Matter of speaking, I can't think of any recent hurricane season that featured two CV storms in July, Hurricanes Emily and Dennis in 2005 aren't considered CV storms although they originated from a tropical wave.


1979 is the other recent example. 1989 and 1990 got their second Cape Verde storm on August 1st and 2nd.
Member Since: July 13, 2006 Posts: 13 Comments: 5368
I would like to hear Joe Bastardi's take on Dorian.
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At what location does a storm need to be for recon to be sent out?
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"HIGH" come on!!!!! Move that thing more west please!! Lol
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Quoting 2339. SecretStormNerd:


We almost named my last son Dorian. We went with Declan, though.


Lucky guess! :)
Member Since: May 25, 2012 Posts: 0 Comments: 2043
Quoting 2349. Hurricanes305:
Does anyone else notice a trend Andrea was almost a near hurricane but quickly weaken, Chantal unexpectedly got to 65mph in strong trade winds and now Dorian. I see a dangerous pattern beginning to unfold like what I said earlier the Atlantic is attempting to turn on the switch.


the switch is on a timer...and its almost time
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Quoting 2342. Tazmanian:
.


Lol. I think all mode runs where miss up even the gfs two day a go it drop the storm


I'll give it credit though for sniffing out the storm from 200+ hours out to about 48 hours out before it dropped it.
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GM! Looking at morn sat pics TD looks like an eye like feature already developing...well on its way on being stronger at 11am update
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Quoting 2323. LargoFl:
still no idea if this will hit florida or not huh?..maybe by the weekend they will know better.....


Dorian is a long way out. Time to sit back and watch it wander across the Atlantic. Should know better in a few days where it might go.
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All I needed is a track like Levi put on his website. It would be perfect. But now... I'm desperate by the look of the models (except the GFS)
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I wonder if Dexter has a wind shear forecast for Dorian's projected path.
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NHC has it labeled as Dorian on their 8am ATCF, but we are going to have to wait until 11AM EST for the official report of Tropical Storm Dorian. We'll give it an hour.
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Does anyone else notice a trend Andrea was almost a near hurricane but quickly weaken, Chantal unexpectedly got to 65mph in strong trade winds and now Dorian. I see a dangerous pattern beginning to unfold like what I said earlier the Atlantic is attempting to turn on the switch.
Member Since: May 25, 2012 Posts: 0 Comments: 2043
Quoting 2315. allancalderini:
He is stronger than what most think he would peak.


Looks like my prediction of 80mph cane into FL isn't so far fetched after all...
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Good morning, afternoon, evening everyone. A pleasant 76 degrees with a high of 98 expected. Looks like we will see Dorian at 11. But can he get past the dry air and then the upper low sheer after that.

Breakfast's on the sideboard: whole wheat pancakes with fruit sauce, egg burritos with cheese and chorizo, cheesy grits and shrimp, cinnamon streusel coffee cake, bagels with low fat cream cheese and jelly, yogurt, fresh fruit and orange, apple or cranberry juice. Enjoy!
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Quoting 2337. LargoFl:
notice one model has it coming right into south florida......


That is the XTRP model. It would have to literally go in a straight line for that to happen. It will be a few days before we really have a good idea where it will go
Member Since: August 18, 2011 Posts: 0 Comments: 635
Quoting 2327. Tornado6042008X:
I see we have Tropical Storm Dorian now. Not looking that bad at all this morning.

The second Cape Verde storm in July. This could mean something big down the road of the 2013 hurricane season. I wonder if we will end up breaking the blog again?


Yes. It will break. Recommend wearing hard hat and goggles when it starts to rev up.
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Quoting 2321. CybrTeddy:
Also kudos to the ECMWF for missing yet another tropical cyclone.
.


Lol. I think all mode runs where miss up even the gfs two day a go it drop the storm
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2341. Ed22
Yes we have tropical depression four could be named later in the 2pm advisory. The blob off the coast north and south Carolina could development is possible later down the week into the weekend, let see what with that blob.
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Wow we may get a Hurricane!
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Quoting 2298. StormWx:
Dorian is born. What an odd name for a storm. I've never met any named that before. If i had a choice for the D storm it would be Devondre, Da-Shawn or most likely De-wanda. But thats just me.


We almost named my last son Dorian. We went with Declan, though.
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Quoting 2327. Tornado6042008X:
I see we have Tropical Storm Dorian now. Not looking that bad at all this morning.

The second Cape Verde storm in July. This could mean something big down the road of the 2013 hurricane season. I wonder if we will end up breaking the blog again?


Yes, it has significant implications for our upcoming hurricane season. Not even 2008 had two July CV storms. Matter of speaking, I can't think of any recent hurricane season that featured two CV storms in July, Hurricanes Emily and Dennis in 2005 aren't considered CV storms although they originated from a tropical wave.
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2337. LargoFl
notice one model has it coming right into south florida......
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2336. Grothar
Quoting 2303. mikatnight:
Good Morning!
7:04 am (11:04 GMT)

The sun rises over Lantana as a helicopter flies overhead.

Oh, Dexter? I believe you said something to the effect that there was no way 98L would become Dorian? Dexter...?

Hmmmm. I maybe should have mentioned that one should consider the possibility that Dexter's forecasts could be based on the probability that he actually wants to eat crow.


Mik, you think we can have a "Dexter Box"?
Member Since: July 17, 2009 Posts: 71 Comments: 27397
2335. JRRP
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Quoting 2319. CybrTeddy:
Morning all! I see we have Tropical Storm Dorian. We're now up to speed with 2011 and 2012. Already up to 50mph too!



Wow look at the outflow beginning to occur I can't wait to see what the NHC discussion is shear is almost nonexistent based on the satellite and an anticyclonic flow is starting to take over thank goodness it still has to content with cool waters but the way its looking now it will just slow development till it warms up again and allow this to deepen before reaching the Islands It would seems the GFS was right on it previous runs all along. Northern need to be watching it closely. As they might be dealing with a strengthening TS.
Member Since: May 25, 2012 Posts: 0 Comments: 2043
Quoting 2330. boltdwright:


What site do you get these from?

From Here
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No on that it is 50MPH!
Quoting 2301. weatherlover94:



according to this it's 40

Link
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I think Dorian heads for the Bahamas and heads into Florida for final destination, misses the front that heads off the East Coast north of Dorian's path
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Quoting 2287. Neapolitan:
Updated:

AL, 04, 2013072412, , BEST, 0, 140N, 290W, 45, 1002, TS, 34, NEQ, 40, 30, 0, 30, 1012, 150, 20, 0, 0, L, 0, , 0, 0, DORIAN, D,

Yowza...


What site do you get these from?
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2329. JRRP
Quoting CybrTeddy:
Also congratulations to the ECMWF for missing yet another tropical cyclone.

LOL
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Quoting 2321. CybrTeddy:
Also congratulations to the ECMWF for missing yet another tropical cyclone.
Lol.Well it did pick this up and at the strongest had it as a 40mph storm then sent it right into the strong high which is practically impossible..
Quoting 2322. allancalderini:
Washi we might get a hurricane after all XD.
Shhh don't say that...
Member Since: August 14, 2010 Posts: 10 Comments: 18733

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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.

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