Two African waves, 92L and 93L, worth watching

By: Dr. Jeff Masters , 2:59 PM GMT on August 11, 2011

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An African wave is near 13°N 35°W, about 700 miles west-southwest of the Cape Verde Islands. This system, (Invest 92L), is moving west to west-northwest at 10 - 15 mph, and has the potential to develop into a tropical depression or tropical storm before arriving near the northern Lesser Antilles Islands early next week. Recent visible satellite loops show that 92L has less heavy thunderstorm activity near where it is trying to develop its circulation center than yesterday. Water vapor satellite loops that a large area of dry air lies just to the west of 92L, but the atmosphere in the immediate vicinity of 92L is moist. Even so, the decline of heavy thunderstorm activity since yesterday implies that dry air is probably working its way into 92L. The SHIPS model and University of Wisconsin CIMSS wind shear analysis are showing moderate wind shear of 10 - 15 knots affecting 92L. Sea surface temperatures are 26.5° - 27°C, which is very close to the 26.5°C threshold usually needed to support a tropical storm.


Figure 1. Morning satellite photo of Invest 92L and Invest 93L.

Forecast for 92L
Low to moderate wind shear of 5 - 15 knots is predicted along 92L's path over the coming three days, which should allow the storm to organize, assuming it can shut out any incursions of dry air that might intrude. The latest 00Z and 06Z model runs of the four best models for predicting tropical storm formation (GFS, ECMWF, NOGAPS, and UKMET) show weak development or no development of 92L, and NHC gave 92L a 30% chance of developing into a tropical depression by Saturday morning in their 8am outlook. A steady west to west-northwest motion for 92L is predicted by all of the models, which would put the storm in the vicinity of the northern Lesser Antilles Islands by Sunday. On Saturday and Sunday, 92L is expected to enter a region where an upper-level low pressure system will bring high wind shear of 20 knots to the storm, which should slow development. This upper-level low is also expected to turn 92L more to the northwest, so the storm is likely to pass north of the Lesser Antilles, though may pass close enough to give heavy rains to the northernmost islands. It is too early to know if 92L will recurve out to sea and potentially threaten Bermuda, or continue to the northwest towards the U.S. East Coast.

93L
An African wave that emerged off the coast of Africa is near 10°N 22°W, a few hundred miles south of the Cape Verde Islands. This system, (Invest 93L), is also moving west at 10 - 15 mph, and has the potential to develop into a tropical depression or tropical storm before arriving near the northern Lesser Antilles Islands near the middle of next week. Recent visible satellite loops show that 93L has a decent amount of heavy thunderstorms, but this activity is not well organized. There is not much spin associated with 93L yet. 93L is fairly well-protected from dry air to its north and west. The SHIPS model and University of Wisconsin CIMSS wind shear analysis are showing moderate wind shear of 10 - 20 knots affecting 93L. Sea surface temperatures are 27.5°C, which is one degree above the 26.5°C threshold usually needed to support a tropical storm.

Forecast for 93L
Moderate wind shear below 20 knots is predicted along 93L's path over the coming five days, which should allow the storm to steadily organize. 93L is about 600 miles east of 92L, which is close enough that the two systems may interfere with each others' organization. The latest 00Z and 06Z model runs of the four best models for predicting tropical storm formation (GFS, ECMWF, NOGAPS, and UKMET), have only one model, the GFS, that is indicating significant development of 93L. This model brings 93L near the northern Lesser Antilles Islands by Wednesday. NHC gave 93L a 20% chance of developing into a tropical depression by Saturday morning in their 8am outlook. Due to moister air, the potential for less wind shear, and a more southerly track, 93L is probably a greater threat to the Lesser Antilles than 92L.

Jeff Masters

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Quoting USAFwxguy:


Thank you. Are you really in ID, and on a tropics forum?


Some of us are in Canada (and not on the coast) in this forum. Storms in the Gulf tend to greatly affect our weather, only a week or so later.
Member Since: Posts: Comments:
Quoting Cotillion:


Well, say global warming is being borne out...

Given how some storms are very tenacious: Epsilon, Grace, Vince, Alberto (1988), Laura, Debbie (1961), Faith...

Storms are going to be found in weirder places and further north. Both in terms of intensity, but also cyclogenesis. That's not just including advances in satellite coverage.

The theoretical question of: 'What would happen if a tropical storm\hurricane hit Europe?' would only become closer and closer to a real question.

(Unless the THC got shutdown).
I do know in warmer periods England / Eire have been impacted by hurricane style storms. And there are tracks of storms from the 1890s [IIRC] which fetch up near Iceland.... so such activity is not completely unprecedented. And didn't we have Muifa up near Korea?
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Quoting TropicalAnalystwx13:


I would love that kind of weather. Except...It doesn't snow much there, does it?
no, trust me you wouldn't. It gets old fast

No snow either. Although there are 6-10,000 ft mountains throughout Southern California which do get a good amount of snow during the Winter.

Further north, around central and northern California, the Sierra Nevadas get loads of snow. Last year (from Jul-Jun) the Mammoth mountain ski resort received 670 inches (55 ft) of Snow.
Member Since: August 24, 2010 Posts: 19 Comments: 4357
Quoting PcolaDan:


Water rights battles (literally) have a loooong history here. Can't imagine how bad it would get trying to do something like that. And back door deals?!?!?! And politicing? And... you get the idea.


Enter the Babel-fish!
Its amazing how clear it all instantly becomes when we suddenly speak/read the same language.
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No one can pinpoint precisely when or if these waves will make US landfall. The best way we can do is hope for the best and prepare for the worst. Because like it or not, someday, our luck WILL run out.
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Quoting alex14:


Where are you getting this information?





1st hes nothing more then a troll and downcasting he downcast a lot of thing 2nd plzs try not too Quote him some of us or many have him on Ingore

Member Since: May 21, 2006 Posts: 5091 Comments: 115081
I am not liking the 18Z GFS run at all (still compiling I think, VERY new to actually watching these runs)

Link
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Quoting USAFwxguy:


Oh it very well still may. This is but one solution from the GFS, a full 13 days into the future.

Conan and Andy might make a more accurate forecast of what to expect that far into the future.


Weather and humor.....(I like this guy!)
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Quoting PlazaRed:
585. KEEPEROFTHEGATE
Not wanting to appear crazy or out on a limb with this as I don't really understand the exact geographical layout of the lower US states but if the US can build a pipeline to bring oil from Alaska and across deserts and oil is a nasty thing to transport, surly their engineers can build a pipeline to transport water from a river like the Mississippi to the drought stricken areas even if it takes some time, it will be there for the future.
Oh Evening everybody!


Water rights battles (literally) have a loooong history here. Can't imagine how bad it would get trying to do something like that. And back door deals?!?!?! And politicing? And... you get the idea.
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Member Since: June 9, 2007 Posts: 4 Comments: 15889
645. JLPR2
Quoting TropicalAnalystwx13:

Your right, its the remnants of Emily.


No, Emily's remnants kept moving NE and is somewhere in this general area, that area was left behind by Emily, it is somewhat related to our notorious storm.
Member Since: September 4, 2007 Posts: 7 Comments: 8690
Quoting TomTaylor:
cool vid

I don't live in Texas, but I wish we got that kind of weather here in Southern California. All we get is dreary, gloomy, marine layer. Which is basically a low level blanket of clouds that provides no rain and keeps us cool and cloudy. Blankets us every night, burns off slightly during the afternoon, but still hangs along the coast.

Lame weather for sure


I would love that kind of weather. Except...It doesn't snow much there, does it?
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Quoting BahaHurican:
Yeah.... hard 2 believe a Hurricane can hit that far north.... but some stuff I was looking at earlier this year was implying that SSTs are well above average up there as well, meaning water warm enough to keep a warm core system going a wee bit longer....


Well, say global warming is being borne out...

Given how some storms are very tenacious: Epsilon, Grace, Vince, Alberto (1988), Laura, Debbie (1961), Faith...

Storms are going to be found in weirder places and further north. Both in terms of intensity, but also cyclogenesis. That's not just including advances in satellite coverage.

The theoretical question of: 'What would happen if a tropical storm\hurricane hit Europe?' would only become closer and closer to a real question.

(Unless the THC got shutdown).
Member Since: Posts: Comments:
Quoting Neapolitan:
I shot this earlier today just so I could remind our central Texas WUers of something they may not have seen for a really long time:


Rain (rayn) - 1. (noun) Water falling in drops condensed from vapor in the atmosphere.
cool vid

I don't live in Texas, but I wish we got that kind of weather here in Southern California. All we get is dreary, gloomy, marine layer. Which is basically a low level blanket of clouds that provides no rain and keeps us cool and cloudy. Blankets us every night, burns off slightly during the afternoon, but still hangs along the coast.

Lame weather for sure
Member Since: August 24, 2010 Posts: 19 Comments: 4357
Quoting USAFwxguy:


Oh it very well still may. This is but one solution from the GFS, a full 13 days into the future.

Conan and Andy might make a more accurate forecast of what to expect that far into the future.


Oh definitely. It wouldn't be wise to put any stock into this with it being nearly two weeks away.
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Quoting TomTaylor:


ruh-roh

just one model run though. Nearly two weeks out too


Kinda glad we're in the crosshairs now, not too worried. We'll see if even develops first.
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Quoting USAFwxguy:
Shades of Hugo... landfall wise.



That just makes me sick. I lost power for weeks and I live well inland in NC.
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Quoting HOTWHEELS99:
they are predicting alot of dry air and shear the next 4 weeks causing alot of storms to be like emily and pittle out or stay out to sea hope we get that lucky all season


Where are you getting this information?
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Quoting JLPR2:


That's not Emily.

Your right, its the remnants of Emily.
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634. JLPR2
Quoting TropicalAnalystwx13:
Hey Ex-Emily, whatcha doing?



That's not Emily.
Member Since: September 4, 2007 Posts: 7 Comments: 8690
Quoting USAFwxguy:
Shades of Hugo... landfall wise.



ruh-roh

just one model run though. Nearly two weeks out too
Member Since: August 24, 2010 Posts: 19 Comments: 4357
Quoting USAFwxguy:
Shades of Hugo... landfall wise.



GFS did a bit of that with Danielle last year early on before deciding it'll recurve.
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Quoting USAFwxguy:
Shades of Hugo... landfall wise.



Wow, that looks like a strong system. So much for it going out to sea (Sad face).
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Quoting bluenosedave:


I would say as far north as Newfoundland. They took a bad hit last year from Ivan, worse than Nova Scotia got from Earl.
Yeah.... hard 2 believe a Hurricane can hit that far north.... but some stuff I was looking at earlier this year was implying that SSTs are well above average up there as well, meaning water warm enough to keep a warm core system going a wee bit longer....
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Q: Do you think Invest 92L will develop? If so, when?

A. Tomorrow
B. Saturday
C. Sunday
D. Monday
E. No, it won't develop

Q: Do you think Invest 93L will develop? If so, when?

A. Tomorrow
B. Saturday
C. Sunday
D. Monday
E. No, it won't develop
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Quoting Neapolitan:
I shot this earlier today just so I could remind our central Texas WUers of something they may not have seen for a really long time:


Rain (rayn) - 1. (noun) Water falling in drops condensed from vapor in the atmosphere.


Internet Hoax.

lol we only have a 20% chance.
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Quoting PlazaRed:
585. KEEPEROFTHEGATE
Not wanting to appear crazy or out on a limb with this as I don't really understand the exact geographical layout of the lower US states but if the US can build a pipeline to bring oil from Alaska and across deserts and oil is a nasty thing to transport, surly their engineers can build a pipeline to transport water from a river like the Mississippi to the drought stricken areas even if it takes some time, it will be there for the future.
Oh Evening everybody!
i agree
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Quoting TropicalAnalystwx13:
Hey Emily, whatya doing?



NOOOOOOOOOOOOOOO!
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92l and 93l seem to be pretty close to eachother. if one develops will it eat or destroy the other because they are do close? tia!
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Quoting CybrTeddy:


Really? My local news in Florida said 93L and 92L both have a chance to develop but shook it off as 'not a threat to land'.. strange enough they posted the spaghetti models for 92L and not for 93L.

Must be watching WFTV in Orlando.
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Quoting beell:
Get your bets down soon. Only 40 or 50 model runs remaining!


LOL beell...good one.
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Hey Ex-Emily, whatcha doing?

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Quoting tropicfreak:
What's so bad about saying?


Repeating a post that has been removed, however baffling to you, may get you banned. Ask privately.
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Our NC weatherman (WRAL) mentioned both 92L and 93L but didn't even point to any models. Just said "We'll watch it" and "It's the time of year to watch waves coming off of Africa".

Way too early to know. Just fun to watch for now.
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I shot this earlier today just so I could remind our central Texas WUers of something they may not have seen for a really long time:


Rain (rayn) - 1. (noun) Water falling in drops condensed from vapor in the atmosphere.
Member Since: Posts: Comments:
585. KEEPEROFTHEGATE
Not wanting to appear crazy or out on a limb with this as I don't really understand the exact geographical layout of the lower US states but if the US can build a pipeline to bring oil from Alaska and across deserts and oil is a nasty thing to transport, surly their engineers can build a pipeline to transport water from a river like the Mississippi to the drought stricken areas even if it takes some time, it will be there for the future.
Oh Evening everybody!
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Quoting HOTWHEELS99:
my money is on our local weather people here in florida and they just said again at 6pm 92 and 93 will go out to sea if not fizzle out


Really? My local news in Florida said 93L and 92L both have a chance to develop but shook it off as 'not a threat to land'.. strange enough they posted the spaghetti models for 92L and not for 93L.
Member Since: July 8, 2005 Posts: 259 Comments: 24017
610. MTWX
Spit like substance falling from sky in Texas!!

Link
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Invest 93L is better organized than Invest 92L right now, but it will be interesting to see if it is vice-versa after 92L separates from the ITCZ and begins to sustain itself.

It will be a very close call to see which one becomes a tropical depression, if one or both of them even become a TD.

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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.