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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Quoting KEEPEROFTHEGATE:
no thats because some people minuses everyones posts
I know Keeper, I was venting....LOL
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Quoting Tazmanian:



ok


ok
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Quoting msgambler:
I am hidden cause everyone thinks I am a troll I guess and they are ignoring me.
no thats because some people minuses everyones posts
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Quoting 954FtLCane:
Drag queens have taken a hold of this blog!!!!
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Quoting TropicalAnalystwx13:


WHOA!

Hold on Taz

I'm not like that...



ok
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Quoting floridaT:
xcool tropical hollywood msgambler will dewey why are ya all hidden?


check you filter at top and see what it shows
Member Since: July 18, 2009 Posts: 1 Comments: 994
Quoting floridaT:
xcool tropical hollywood msgambler will dewey why are ya all hidden?
I am hidden cause everyone thinks I am a troll I guess and they are ignoring me.
Member Since: February 27, 2010 Posts: 0 Comments: 1125
90L fat day
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Quoting Tazmanian:



LOL



you guys are funny


i love you


WHOA!

Hold on Taz

I'm not like that...
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831. xcool
90l doom days lol
Member Since: September 26, 2009 Posts: 2 Comments: 15620
xcool tropical hollywood msgambler will dewey why are ya all hidden?
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Quoting hunkerdown:
not you, a certain somebody who repeatedly posts GW crap who needs to find himself a dedicated GW blog, or visit al gore...


agreed!!
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Quoting hunkerdown:
not you, a certain somebody who repeatedly posts GW crap who needs to find himself a dedicated GW blog, or visit al gore...


lmao
Member Since: July 1, 2005 Posts: 10 Comments: 1683
i think 90L is playing with us
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why are all your coments hidden?
Member Since: September 2, 2007 Posts: 0 Comments: 1043
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Im not gonna touch thatone Taz lol
Member Since: July 18, 2009 Posts: 1 Comments: 994
Quoting Tazmanian:



LOL



you guys are funny


i love you
and you thought i was bad, i was only gonna dish out 24....
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Quoting TropicalAnalystwx13:


A 48 hour ban :P



LOL



you guys are funny


i love you
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Quoting ho77yw00d:


ME? what did I do now? lol
not you, a certain somebody who repeatedly posts GW crap who needs to find himself a dedicated GW blog, or visit al gore...
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Quoting will45:


just da heat in russia lol



hmmmmmmmmmmm... well ok then lol
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814. ho77yw00d

No i dont think he was talking about you
Member Since: July 18, 2009 Posts: 1 Comments: 994
2 more weeks for most earthly. I can't wait....LOL
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Quoting Tazmanian:
holy we cow i was post 700 and 800



what do i win


A 48 hour ban :P
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Quoting xcool:
When using Dr. Masters' blog, please refrain from posting material not relevant to the discussion of tropical weather, or the topic of the blog When using Dr. Masters' blog, please refrain from posting material not relevant to the discussion of tropical weather, or the topic of the blog


ME? what did I do now? lol
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813. xcool
hunkerdown .lmao
Member Since: September 26, 2009 Posts: 2 Comments: 15620
well all my loves good night
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Quoting xcool:
When using Dr. Masters' blog, please refrain from posting material not relevant to the discussion of tropical weather, or the topic of the blog When using Dr. Masters' blog, please refrain from posting material not relevant to the discussion of tropical weather, or the topic of the blog
this is a recording....
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Quoting hunkerdown:
lets see, it starts with 24...



ouch lol
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Quoting Tazmanian:
holy we cow i was post 700 and 800



what do i win
lets see, it starts with 24...
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Quoting ho77yw00d:
did he specifically say GM in his blog? or just heat in russia?


just da heat in russia lol
Member Since: July 18, 2009 Posts: 1 Comments: 994
806. xcool
When using Dr. Masters' blog, please refrain from posting material not relevant to the discussion of tropical weather, or the topic of the blog When using Dr. Masters' blog, please refrain from posting material not relevant to the discussion of tropical weather, or the topic of the blog
Member Since: September 26, 2009 Posts: 2 Comments: 15620
Quoting Tazmanian:



not yet
Member Since: February 27, 2010 Posts: 0 Comments: 1125
holy we cow i was post 700 and 800



what do i win
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Quoting Tazmanian:
i think 90L is starting too come back too life


any one say this ia dead well eat raw fish
sushi good :)
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did he specifically say Gw in his blog? or just heat in russia?
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90L lives on
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Quoting msgambler:
You find the answer to your computer problem Taz?



not yet
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i think 90L is starting too come back too life


any one say this ia dead well eat raw fish
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Quoting serialteg:


is GW short for Girlsgone Wild?


at least that would be interesting HA
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Quoting Tazmanian:
well good night
You find the answer to your computer problem Taz?
Member Since: February 27, 2010 Posts: 0 Comments: 1125
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

well the good DR Masters mentioned something about the heat in russia and they jumped all over it lol
Member Since: July 18, 2009 Posts: 1 Comments: 994
Quoting ho77yw00d:


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


Masters will have a GW this coming week. And when he posts it, I'm posting a tropics on my blog, and we can all go there :)
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792. xcool
:))))))
Member Since: September 26, 2009 Posts: 2 Comments: 15620
well good night
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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.