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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Wind is East at 21 with gusts to 31 here on the NC Coast!!!!
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2010 Hurricane season "The Year of the Blobs"
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Quoting JLPR2:
Well this is interesting, 90L and the TW separated so what the CMC develops at 40W is the TW that was related to 90L

I saw that too
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Quoting CyclonicVoyage:
However, and of note, it rained here on the SECNTRL coast of Fla for the first time in A LONG TIME. Seen the clouds coming from the SW this morning and said to myself, hey, it might rain today. Have to see if this persists, so far this year it hasn't.
in sw fl thats all we have been gettin is rain
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737. KYDan
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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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However, and of note, it rained here on the SECNTRL coast of Fla for the first time in A LONG TIME. Seen the clouds coming from the SW this morning and said to myself, hey, it might rain today. Have to see if this persists, so far this year it hasn't.
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Quoting StSimonsIslandGAGuy:
Time to go tend bar, y'all have fun! I'll look in (much) later to see what 90L is up to.
ya mean all that time all that talk about degrees and your a bartender lmao
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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.



:)
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Quoting Tazmanian:
dos any have a Hewlett Packard Pavilion dv5-1254us



if so PM me
have a dv-5 but not sure about th other numbers taz
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Evening All.

of the two models I looked at (GFS & CMC) both still develop 90L's circulation. GFS has a rather formidable storm in striking distance 7 days from now heading WNW with highs stacked above. Looking at the pressure pattern thus far I tend to favor the GFS over the CMC showing troughiness on the east coast.

GFS168hrs (7Days)



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729. JLPR2
Well this is interesting, 90L and the TW separated so what the CMC develops at 40W is the TW that was related to 90L
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728. KYDan
Quoting CybrTeddy:


The African wave does not require the ITCZ's assistance to sustain itself and 90L does. You'll have to ask someone else as my weak point in the tropics is the ITCZ.


OK. Thanks again for the reply.

Dan
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hey snow im with ya brother we have become a country of tow the line and when ya think about it a weatherman if hes right 60 % of the time thats good but heaven forbid he predicts something outher than the higher ups. thats why this blog is soo soo soo popular
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Quoting KYDan:


I am certainly not going to disagree, but it appears to be following 90L like a hound dog on a trail. How can one be tracking with the ITCZ and the other one not?

What am I missing in watching the satellite loops? Thanks for the help.

Dan


The African wave does not require the ITCZ's assistance to sustain itself and 90L does. You'll have to ask someone else as my weak point in the tropics is the ITCZ.
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Quoting earthlydragonfly:
Evening folks.... I tell you what... I have been watching the CMC and if that is close we may see a little bit of a Fujiwhara Effect when 90l and the disturbance off the coast of Africa before they combine... Go to the CMC run and it starts at about 48 hours to when they start to combine at 102 hours.
This could be a year we learn a lot from so many different kinds of situations. Like earlier when Bonnie interacted with the ULL.. very interesting stuff.
just to clarify, the "systems" must be tropical cyclones for there to be a real fujiwhara...that being said, my thinking is that the wave to the east will "take over" 90L and for a new POTENTIAL invest, possibly becoming 91L. Ultimately, will there be any formation, at this point I have my doubts. One thing that this year has shown so far is that areas of waves/low pressure that show potential are having a tough time progressing, or for a better term, getting their groove on. As August progresses things may improve formation-wise but for now I just don;t see it there. Due to these hampering problems, models are even less useless than normal at predicting cyclogenesis let alone a track of something. Until the waves can prove they have the ability for formation, the models can be thrown out the door.
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724. KYDan
Quoting CybrTeddy:


SHIPS analyzed 5 knot shear or so for most of 90L's run so I suspect conditions would be similar to this for the wave behind it. What's going to kill 90L is because of its attachment to the ITCZ and the influence of a larger tropical wave that isn't attached to the ITCZ.


I am certainly not going to disagree, but it appears to be following 90L like a hound dog on a trail. How can one be tracking with the ITCZ and the other one not?

What am I missing in watching the satellite loops? Thanks for the help.

Dan
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723. JLPR2
Quoting CybrTeddy:


It will be vice versa, the wave's circulation is much more broad and 90L's very small. Naturally, the larger one will win.


well yeah, you got a big point there. XD
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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.



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Quoting JLPR2:


It seems that convection of the other wave is now almost on top of 90L's 850mb vort, maybe 90L could steal some of it?


It will be vice versa, the wave's circulation is much more broad and 90L's very small. Naturally, the larger one will win.
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Quoting floridaT:
you mean back in the day when you could give your opinion? when weather men were weathermen?


Without being threatened with your life by alarmists! Yea! The good days! :)
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719. JLPR2
Quoting CybrTeddy:


SHIPS analyzed 5 knot shear or so for most of 90L's run so I suspect conditions would be similar to this for the wave behind it. What's going to kill 90L is because of its attachment to the ITCZ and the influence of a larger tropical wave that isn't attached to the ITCZ.


It seems that convection of the other wave is now almost on top of 90L's 850mb vort, maybe 90L could steal some of it?
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dos any have a Hewlett Packard Pavilion dv5-1254us



if so PM me
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Quoting KYDan:
If 90L is looking sick and does not appear to be able to develop, and I do realize that the wave that is behind 90L may have something to do with the lack of development, what conditions are going to change in the next 48 hours that will allow for the wave that swallows 90L to do any better at survival?


SHIPS analyzed 5 knot shear or so for most of 90L's run so I suspect conditions would be similar to this for the wave behind it. What's going to kill 90L is because of its attachment to the ITCZ and the influence of a larger tropical wave that isn't attached to the ITCZ.
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716. JLPR2
Quoting whs2012:


Interesting...



yeah, Either way another system eats 90L XD

The TW is shown moving WNW, then it weakens and adds a little to the mix.
But the CMC has an awesome imagination and can get very creative. XD
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715. KYDan
If 90L is looking sick and does not appear to be able to develop, and I do realize that the wave that is behind 90L may have something to do with the lack of development, what conditions are going to change in the next 48 hours that will allow for the wave that swallows 90L to do any better at survival?
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Quoting thelmores:


I didn't say the Negative MJO was going to "kill" 90L....... was trying more to point out that it is not a "positive" factor. At this point, 90L has few positive factors going for it! The biggest detriment however, is the wave to the East........


I do not believe 90L on its own will develop. But 90L has a vigorous MLC, your adding a vigorous MLC to a very vigorous tropical wave which on its own could develop without 90L's help anyways.
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Quoting Snowlover123:


Maybe he's retired?

I’m a former television meteorologist who spent 25 years on the air and who also operates a weather technology and content business, as well as continues daily forecasting on radio, just for fun.

http://wattsupwiththat.com/about2/
you mean back in the day when you could give your opinion? when weather men were weathermen?
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Quoting earthlydragonfly:
Evening folks.... I tell you what... I have been watching the CMC and if that is close we may see a little bit of a Fujiwhara Effect when 90l and the disturbance off the coast of Africa before they combine... Go to the CMC run and it starts at about 48 hours to when they start to combine at 102 hours.
This could be a year we learn a lot from so many different kinds of situations. Like earlier when Bonnie interacted with the ULL.. very interesting stuff.


from that, it looks like 90L eats the wave! LOL
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Quoting KoritheMan:


True. But as we saw with Florence, large systems tend to take awhile to consolidate.



Yup.


Yup, but strong amounts of dry air, lower SSTs, and shear where impacting the initial development phase in a typical El Nino fashion, although I do believe this will gradually develop rather than quickly become a storm.
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709. JLPR2
Quoting earthlydragonfly:
Evening folks.... I tell you what... I have been watching the CMC and if that is close we may see a little bit of a Fujiwhara Effect when 90l and the disturbance off the coast of Africa before they combine... Go to the CMC run and it starts at about 48 hours to when they start to combine at 102 hours.
This could be a year we learn a lot from so many different kinds of situations. Like earlier when Bonnie interacted with the ULL.. very interesting stuff.


Thats not the TW, thats 90L, the CMC is nuts LOL!
It develops a 850mb vort near 10n and 40w and has it interacting with 90L which is at 30somethingW.
Well the vort at 40W actually exists.
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699. What would you say would be the first opportunity for it to become a depression?
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Quoting CybrTeddy:


Negative MJO doesn't kill off systems, just suppresses thunderstorms making it less likely that a disturbance will pop up.


I didn't say the Negative MJO was going to "kill" 90L....... was trying more to point out that it is not a "positive" factor. At this point, 90L has few positive factors going for it! The biggest detriment however, is the wave to the East........
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hey i was post 700 what do i win
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Quoting StSimonsIslandGAGuy:
Anthony Watts also claims to be AMS certified on this site.

And this site

And so on.

those lists have no one listed as AMS Seal of approval .. they all say "AMS certified" is it not possible that there was simply an error in distinction made by those assembling the lists as opposed to Anthony Watts himself? Seems like an easy mistake.
Member Since: August 27, 2008 Posts: 0 Comments: 1497
Evening folks.... I tell you what... I have been watching the CMC and if that is close we may see a little bit of a Fujiwhara Effect when 90l and the disturbance off the coast of Africa before they combine... Go to the CMC run and it starts at about 48 hours to when they start to combine at 102 hours.
This could be a year we learn a lot from so many different kinds of situations. Like earlier when Bonnie interacted with the ULL.. very interesting stuff.
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Quoting BreadandCircuses:
................Don't Feed The.................






re ported
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Quoting CybrTeddy:


Florence in 2006 is a good example. A slow moving tropical wave interacted with a vigorous tropical wave moving off the coast and formed a large system that eventually became a Hurricane. Conditions however are far more favorable than they where for Florence.


True. But as we saw with Florence, large systems tend to take awhile to consolidate.

Quoting ElConando:


Insteresting that it shows a neutral Mjo in the Atlantic at the end of the run.


Yup.
Member Since: March 7, 2007 Posts: 602 Comments: 21231
692. Its incredible how much you remember about the formation of some systems.
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Quoting hcubed:


Not having one is one thing.

You stated "...And he used to claim AMS certification until he was busted for not having it..."

Proof?

I feel like thats more important .... if he didnt claim something that wasnt true, wheres the problem?
Member Since: August 27, 2008 Posts: 0 Comments: 1497
Quoting thelmores:
Looks to me between the Negative MJO and the encroaching wave from the east, 90L has little chance at this point. Seems pretty obvious to me, 90L is about to become Lunch for the wave to the East!


Negative MJO doesn't kill off systems, just suppresses thunderstorms making it less likely that a disturbance will pop up.
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Quoting StSimonsIslandGAGuy:
CapeObserver, thank you!



I'll be heading out in a bit, but it will be interesting to see if there are any apologies from those who accused me of lying about Anthony Watts not having an AMS certification.

To the disappointment of some, I won't be holding my breath waiting though ;)


Not having one is one thing.

You stated "...And he used to claim AMS certification until he was busted for not having it..."

Proof?
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Quoting KoritheMan:


90L is not the main system. The associated vorticity is almost entirely absent. Divergence and convergence is steadily decreasing with it, as well. The wave to the east is the one to watch, not 90L.

These situations happen from time to time in the tropics. The most recent example I can think of is 2004's Lisa absorbing a convectively active tropical wave near the Cape Verde Islands.


Florence in 2006 is a good example. A slow moving tropical wave interacted with a vigorous tropical wave moving off the coast and formed a large system that eventually became a Hurricane. Conditions however are far more favorable than they where for Florence.
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Looks to me between the Negative MJO and the encroaching wave from the east, 90L has little chance at this point. Seems pretty obvious to me, 90L is about to become Lunch for the wave to the East!
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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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