Little change to 90L; new African tropical wave is worth watching

By: Dr. Jeff Masters , 8:53 PM GMT on July 30, 2010

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Invest 90L is a tropical wave in the eastern Atlantic near 10N 33W with a very limited amount of heavy thunderstorm activity but a decent amount of spin. It does not have a well-defined surface circulation, and has shown little change in organization today. CIMMS wind-shear analyses show a low amount of wind shear (5 - 10 knots) over 90L, and sea surface temperatures are a record warm 29°C. The wave currently is in a moist environment and is not being affected by the dry Saharan Air Layer (SAL) to its northwest. The disturbance has moved far enough away from the Equator to leverage the Earth's spin to help it develop. The Saharan Air Layer with its dust and dry air lurks just to the north of 90L, but the SHIPS model predicts 90L will remain far enough from the dry air over the next five days so that it will not interfere with development.


Figure 1. Afternoon visible satellite image from 2pm EDT 7/30/10 of the relatively tiny 90L, and the large new tropical wave that moved off the coast of Africa yesterday.

Forecast for 90L
One factor inhibiting development of 90L this week will be the Madden-Julian Oscillation (MJO.) The MJO currently favors downward motion over the tropical Atlantic, which will act to decrease the chances of tropical storm formation. The Madden-Julian oscillation is a pattern of enhanced rainfall that travels along the Equator from west to east. The pattern has a wet phase with large-scale rising air and enhanced thunderstorm activity, followed by a dry phase with large-scale sinking air and suppressed thunderstorm activity. Each cycle lasts approximately 30 - 60 days. When the Madden-Julian oscillation is in its wet phase over a hurricane-prone region, the chances for tropical storm activity are greatly increased.

Perhaps the main factor interfering with 90L's development will be the presence of the large tropical wave to the east of 90L that moved off the coast of Africa yesterday. This new wave is large enough and close enough to 90L that it will probably begin to dominate regional weather patterns this weekend, stealing away 90L's inflow of low-level moist air. The new wave may also act to bring sinking air over 90L that will tend to suppress 90L's thunderstorm activity. It may turn out that the new wave will also steal some of 90L's spin, and end up being a threat to develop itself later on this weekend.

The latest 8am EDT (12Z) model runs for 90L show very little in the way of development of the storm. The predominant track forecast takes 90L into or just north of the northern Lesser Antilles Islands about 6 - 8 days from now. Looking at climatology based on research done by Dr. Bob Hart at Florida State University,, 90L has a 19% chance of developing into a tropical cyclone by 2pm Sunday. NHC is putting these odds at 20%. Dr. Hart also has an experimental product showing that historically, about 30% of all tropical cyclones that develop at 90L's current position eventually hit land as a hurricane. Of course, 90L is not yet a tropical cyclone, and I think that the large tropical wave off the coast of Africa will kill 90L this weekend.

Tropical wave in the eastern Caribbean
A tropical wave in the eastern Caribbean, south of the Dominican Republic, is moving west at 15 - 20 mph with no signs of development. The wave is under a high 20 knots of wind shear, due to strong upper-level westerly winds from an upper level low centered north of Puerto Rico. This shear is expected to remain remain high through Saturday. By Sunday, when the wave will be approaching Nicaragua, the wave will be far enough away from the upper level low that shear should fall to the moderate range, 10 - 20 knots. Some development is possible on Sunday, but the wave will have only about a 1-day window to develop before its westerly motion brings it inland over Nicaragua on Monday. NHC is giving this wave a 10% chance of developing into a tropical depression by 2pm Sunday.

Extreme cold records for 2010
In my post yesterday, I reported that fourteen countries had set their all-time hottest temperature record this year. I neglected to mention that one country has also set its coldest temperature in recorded history mark in 2010. Guinea had its coldest temperature in its history on January 9, 2010, when the mercury hit 1.4°C (34.5°F) at Mali-ville in the Labe region. Of the 229 countries with extreme coldest temperature records, 14 of these records have occurred in the past ten years (6% of all countries). There have been five times as many (74) extreme hottest temperature records in the past ten years (33% of all countries.) My source for extreme weather records is Chris Burt, author of Extreme Weather.

New study finds huge drop in the plants that form the base of the oceanic food chain
A study published this week in the journal Nature documents that microscopic marine phytoplankton, which form the basis of the marine food chain, have declined by 40% globally since 1950. Joe Romm at climateprogress.org discusses the implications, using this headline:

Scientists may have found the most devastating impact yet of human-caused global warming — a 40% decline in phytoplankton since 1950 linked to the rise in ocean sea surface temperatures. If confirmed, it may represent the single most important finding of the year in climate science.

I plan to discuss this paper next week.

Next update
I'll have an update this weekend, probably by 8pm EDT Saturday.

Jeff Masters

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well good night
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Quoting earthlydragonfly:


i always seem to come back at the right time!


awwwwwww!!! so sweet
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Quoting will45:


not unless you call GW much lol


NOOOOO!! R U serious? wow is there not a GW blog? I mean seriously not to be rude but I love this blog but all the GW stuff drives me nutts! I say all the people who want to thrive on GW find a GW blog (problem solved) lol
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i remembered!

where is STORMNO
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Quoting msgambler:
your such a suckup....LOL


dont u forget it ;)
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Quoting xcool:


Convection will be on the increase with the African wave/Soon-to-be-91L later on.
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your such a suckup....LOL
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Quoting ho77yw00d:
have I missed much?


i always seem to come back at the right time!
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781. xcool
Member Since: September 26, 2009 Posts: 2 Comments: 15684
Quoting ho77yw00d:
have I missed much?


not unless you call GW much lol
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I made a new blog eariler, you should go check it out please...While WU is quiet :D
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Have a good night all enjoy the quiet while it lasts.
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774. JLPR2
I see a very clear rotation with 90L but it is naked, it needs some convection so it can tighten up and with that other TW so close that will be hard.

Link
Member Since: September 4, 2007 Posts: 7 Comments: 8747
773. xcool
poof 97l
Member Since: September 26, 2009 Posts: 2 Comments: 15684
Quoting StSimonsIslandGAGuy:
Oh hey this is the Mike half here.

Going over Get Real's points.

If he claims slander, he can get specific and say so.

One one point, Get Real lied. Rich did link to the AMS official site which gives the information on how the seal of approval and certification changed in 2005.

Also, since Get Real is saying accurately that the "Seal of Approval" was discontinued in 2005, why is Watts still claiming to be certified on all those sites?


He has no degree, and has no credibility.

Oh, and for the record, we co-own the restaurant and pub. And Rich has 3 degrees. One double in Econ and Public policy (undergrad), one MBA, and one MLS.

And he's still waiting for apologies from everyone who accused him of lying when he said Anthony Watts has no AMS certification and no degree.

You're welcome


Did you read my response about those lists?
post #704.
Member Since: August 27, 2008 Posts: 0 Comments: 1497
770. xcool
hmm
Member Since: September 26, 2009 Posts: 2 Comments: 15684
Quoting Orcasystems:
Hmmm the dead zone...Last update and looking forward to see what the morning brings.



AOI

AOI

AOI

AOI

AOI

TS BUSTED FORECAST ALIBI

Welcome to the "WU Twilight Zone"!!
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nic turning with the wave at 10N/60W
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Tropical wave is coming into view.
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Quoting AllStar17:
Just because 90L is gone, there are still several other disturbances out in the Atlantic at this time, including the wave right behind 90L.

Things can go from quiet to "out of control" on a heartbeat!!

Has everyone forgotten Alex? Our 948MB CAT 2 that rapidly intensified (RI), with a pinhole eye. That hurricane covered the eastern 1/2 of the GOM, dropping up to 36" of rain in Monterrey, MX?? On June 30th??

Even last year, we had Bill, Fred, Ida that really could have done very serious damage if their paths were different.
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Quoting GetReal:
I believe that I may be able to put this Anthony Watts AMA controversy to rest, and help some see through the misinformation, and the character assassination regarding Mr. Watts.

I just literally came upon this information by accident.

It appears that Mr Watts did indeed possess the AMA Seal of Approval, up until he retired from broadcasting in 2004. As SSI has stated Mr Watts never possessed the AMA Certification.

What SSI failed to tell everyone, while possibly slandering Mr Watts reputation, is that the AMA revamped the Seal of Approval program in January 2005. American Meteorological Society

Maybe, just maybe, since Mr Watts was retired and no longer involved in television weather, there was no need to obtain the AMA Certification for broadcast purposes.





The thing is, for years, Watts has stood idly by while his name has been placed on list after list of contrarian "experts" as an AMS-certified meteorologist; he's apparently done nothing to set the record straight. Now, while some can try to claim there's no real difference between an AMS--approved broadcaster and an AMS Certified Meteorologist, I contend that Watts' purporting to be the latter while he's only the former is akin to an EMT pretending to be a board-certified cardiologist.
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Just because 90L is gone, there are still several other disturbances out in the Atlantic at this time, including the wave right behind 90L.
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Quoting xcool:
Bordonaro .91l come.

You may be correct xcool as the Wave that appears to be ready to eat 90L for lunch, may enhance Low Level Vorticity, creating 91L, or worse!!

Truthfully, my concern is the TCHP is very, very high. As the upward MJO progresses by 8-8-2010, we may have a Tropical Cyclone explosion. We really do NOT need another "convention of CAT 3, 4 and 5 storms like in 2008!!!
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761. xcool
Bordonaro .91l come.
Member Since: September 26, 2009 Posts: 2 Comments: 15684
Quoting xcool:
bye 90L LOL

Well, it is not the end of the world. Conditions will gradually become more favorable for TC development as August comes along.

I know it appears disappointing, however there is plenty of TCHP untapped.

All is takes is one nasty hurricane, to make a name for itself. And we really do not want things to go crazy in the Tropical Atlantic.
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756. xcool
bye 90L LOL
Member Since: September 26, 2009 Posts: 2 Comments: 15684
Quoting CybrTeddy:


They add to the heat build up, meaning more moisture. Upward MJO style convection in a downward MJO. So yes they are a threat for monsoonal like development.
thanks! the blog seems to have died. i just got kicked off the site for a moment. wonder if i was the only one?:)
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Hmmm the dead zone...Last update and looking forward to see what the morning brings.



AOI

AOI

AOI

AOI

AOI

TS BUSTED FORECAST ALIBI
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Quoting CybrTeddy:
Hello?
are you still there?:)
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Quoting sarahjola:
hi! can you answer this-are those area's in the Caribbean of any concern? they have 2 one at about 65w. and one at about 83w. any thought on those blobs? thanks in advance:)


They add to the heat build up, meaning more moisture. Upward MJO style convection in a downward MJO. So yes they are a threat for monsoonal like development.
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Quoting CybrTeddy:
Hello?
hi! can you answer this-are those area's in the Caribbean of any concern? they have 2 one at about 65w. and one at about 83w. any thought on those blobs? thanks in advance:)
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748. JLPR2
Quoting CybrTeddy:
Hello?


echo... echo...
XD
Member Since: September 4, 2007 Posts: 7 Comments: 8747
Hello?
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745. xcool
Member Since: September 26, 2009 Posts: 2 Comments: 15684
Quoting ElConando:
699. What would you say would be the first opportunity for it to become a depression?


If it does develop, it'll probably at least four days, possibly even longer.
Member Since: March 7, 2007 Posts: 599 Comments: 21165
Quoting MissNadia:
Wind is East at 21 with gusts to 31 here on the NC Coast!!!!


what part are you at Miss?
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i've won the "last post of the blog" a few times before, lol... and me not knowing

that water vapor looks awesome ... energy's out there
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Wind is East at 21 with gusts to 31 here on the NC Coast!!!!
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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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