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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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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Quoting Bipartisanship:


it's getting renumbered to 91l, no worries.
90.5L
Member Since: November 1, 2004 Posts: 25 Comments: 8923
Quoting KoritheMan:


I would like to add that, out of the three models (EWP, CFS, and GFS) forecasting MJO, I agree most strongly with the CFS, based on current convective trends across the basin:



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


I doubt that, it's been sustaining convection (and growing) since it emerged off Africa nor is it dependent on the ITCZ. This also has model support from the ECMWF, GFS, CMC, and NOGAPS. I could be wrong of course, but when you add a potent MLC/LLC (90L) to a vigorous wave its a recipe for a storm. Florence in 2006 formed similar to this.



I think he was more stating the unfavorableness of the synoptic pattern than the future 91L.
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Anyone want to go to my blog and talk tropics?
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Quoting ElConando:


There is a possibility of no development until the second week of August when significant MJO is forecasted to return to the basin. No telling of what will happen when that occurs. However, I would like to give what may soon be a couple of days before I would write it off.


I would like to add that, out of the three models (EWP, CFS, and GFS) forecasting MJO, I agree most strongly with the CFS, based on current convective trends across the basin:

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mode runs has drop 90L all togeter
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Quoting JLPR2:


How about Alex absorbing the TW to its west?


Oh, right. Forgot about that.
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Quoting StSimonsIslandGAGuy:
He never had AMS certification because that requires that he have a meteorological degree.

Here is the page on the differing requirements for the "seal of approval" and "certification"



The "Seal of Approval" no longer even exists anymore, correct? They no longer give it out? Only the "Certification" I believe.
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Quoting Twinkster:
did they not run 00z models for 90L?


hey Twinkster it happens all the time late for model runs and/or late for curent plot it happen all the time so don't be surprised
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Quoting hunkerdown:
maybe you should have stayed in a holiday inn express instead...

maybe, but my employers were paying for it!
the shower was at least hot this morning.
how are you doing hunkerdown? what do you think about this 90L? does it have a chance with that gigantic wave behind it?
the strange thing about this one is it's been entwined with the ICTZ since day one. it just can't seem to get free of it.
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Quoting ElConando:


There is a possibility of no development until the second week of August when significant MJO is forecasted to return to the basin. No telling of what will happen when that occurs. However, I would like to give what may soon be a couple of days before I would write it off.


This is also possible.
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Quoting Snowlover123:
It's really funny. If sea ice wasn't doing as well as it is now, with ice leveling off, the alarmists would be all over it, yet they're completely silent. Haven't mentioned a thing about it. Instead, they're trying to pull apart the credibility of Anthony Watts, which is failing quite substantially.


Okay, I'll mention it: sea ice in the Antarctic is increasing. There are warm spots, such as where the Larso B and Ross ice shelves broke off. But the rest of the continent hasn't shown any clear warming or cooling, and sea ice has increased over the last decade otr so. But note this: that is completely in line with model expectations. True. Models early on predicted that CO2-dominated forcing would have a disproportionately larger effect in the northern hemisphere: there's more land in the north, the ocean's thermal inertia and ability to mix delay temp signals from the absorption of heat, and the circupolar current prevents tropical water--which has been warming consitently for decades--from heating the continent.

(And, of course, Arctic sea ice is shrinking.)
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673. JLPR2
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.


How about Alex absorbing the TW to its west?
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Quoting HaboobsRsweet:
People are saying 90L is RIP because 90L is RIP...it will get taken over. It is too far south as well in my opinion. Synpotic pattern not favroable at the moment either. Soon to be 91L could fizzle out like all the others have. It is just setting up for a big push later in August.


I doubt that, it's been sustaining convection (and growing) since it emerged off Africa nor is it dependent on the ITCZ. This also has model support from the ECMWF, GFS, CMC, and NOGAPS. I could be wrong of course, but when you add a potent MLC/LLC (90L) to a vigorous wave its a recipe for a storm. Florence in 2006 formed similar to this.

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i wounder if they will move 90L a little too the E too the new wave
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Quoting HaboobsRsweet:
People are saying 90L is RIP because 90L is RIP...it will get taken over. It is too far south as well in my opinion. Synpotic pattern not favroable at the moment either. Soon to be 91L could fizzle out like all the others have. It is just setting up for a big push later in August.


There is a possibility of no development until the second week of August when significant MJO is forecasted to return to the basin. No telling of what will happen when that occurs. However, I would like to give what may soon be a couple of days before I would write it off.
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668. JLPR2
Quoting TropicalAnalystwx13:


The wave is taking over 90L :\


That wave has a nicer spin
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Quoting wunderkidcayman:
now now guys before ripping 90L, let us wait for D-MAX to kick in and that is in about 4-7 more hours and no the wave is not taking over 90L, 90L is the main system and the wave is the clothing store and 90L is buying some clothes


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.
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Quoting wunderkidcayman:
now now guys before ripping 90L, let us wait for D-MAX to kick in and that is in about 4-7 more hours and no the wave is not taking over 90L, 90L is the main system and the wave is the clothing store and 90L is buying some clothes


The wave is taking over 90L :\
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Quoting wunderkidcayman:
now now guys before ripping 90L, let us wait for D-MAX to kick in and that is in about 4-7 more hours and no the wave is not taking over 90L, 90L is the main system and the wave is the clothing store and 90L is buying some clothes


Even if that is not true, the way you worded it makes me want to believe lol
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Quoting StSimonsIslandGAGuy:
Arctic sea ice extent still far below normal.



How about the Antarctic ice? If it's Global Warming, Global Sea Ice should be below normal for both poles. If there was a real problem with the ice, you'd see both decreasing, not one. All due to the natural oscillations.
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Quoting wunderkidcayman:
now now guys before ripping 90L, let us wait for D-MAX to kick in and that is in about 4-7 more hours and no the wave is not taking over 90L, 90L is the main system and the wave is the clothing store and 90L is buying some clothes


Love the analogy. LOL.
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Well I learned something new tonight: There is a big difference between having the Seal of Approval from the AMA, and being AMA Certified!


StormW just curious which of the two are you, or possibly both??? Also is there really that big of a difference???
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now now guys before ripping 90L, let us wait for D-MAX to kick in and that is in about 4-7 more hours and no the wave is not taking over 90L, 90L is the main system and the wave is the clothing store and 90L is buying some clothes
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Quoting Chicklit:
Taz, 90L may get absorbed by the wave behind it.



yup am this starting too think that
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*shrugs*
I was just looking for answers wasn't looking to be sarcastic in anyway. In fact, I found out the answer for myself long before I was answered but thanks.
On another point ... if he's never said he was a Purdue grad, what's there to hate on him about? 99% of us have no credentials ... But that doesnt mean we cant make logical arguments.
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Quoting Chicklit:
The distinction between skepticism and ignorance is that a skeptic asks questions and looks for reasons.
The ignorant reject reason and insist on skepticism.

So true...
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Taz, 90L may get absorbed by the wave behind it.
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Quoting TropicalAnalystwx13:
Poll time!

Q: In your opinion, what is the strongest Invest 90L will become in its lifetime.

A. It wont develop

B. Tropical Depression

C. Tropical Storm

D. Hurricane and/or Major Hurricane

No other letters, numbers, or symbols!!!
No other letters, numbers, or symbols
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Quoting StSimonsIslandGAGuy:


He holds a "seal of approval" but is not AMS certified.

Here is the list of certified broadcast meteorologists. His name is not there.


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/
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Quoting TropicalAnalystwx13:
Poll time!

Q: In your opinion, what is the strongest Invest 90L will become in its lifetime.

A. It wont develop

B. Tropical Depression

C. Tropical Storm

D. Hurricane and/or Major Hurricane

No other letters, numbers, or symbols!!!


C
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Quoting TropicalAnalystwx13:
Poll time!

Q: In your opinion, what is the strongest Invest 90L will become in its lifetime.

A. It wont develop

B. Tropical Depression

C. Tropical Storm

D. Hurricane and/or Major Hurricane

No other letters, numbers, or symbols!!!



A
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The distinction between skepticism and ignorance is that a skeptic asks questions and looks for reasons.
The ignorant reject reason and insist on skepticism.
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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 ;)


My pleasure. You got me curious and it was certainly easy to find so I don't understand where all the accusations came from to start with. Very easily verified.
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People are saying 90L is RIP because 90L is RIP...it will get taken over. It is too far south as well in my opinion. Synpotic pattern not favroable at the moment either. Soon to be 91L could fizzle out like all the others have. It is just setting up for a big push later in August.
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Quoting NoNamePub:


90L still on the NAVY site...


It's only a matter of time before it's gone...
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Quoting Chicklit:
Anyway, I'm not a meterologist, and I am not from the NHC, but I did stay at a Comfort Inn last night and I declare 90L moot at this point.
maybe you should have stayed in a holiday inn express instead...
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Quoting hcubed:


I'm still waiting for the link to Watts' past.

If the data isn't produced, then I guess it's not true.


Pardon the interruption, but--assuming you're talking about Anthony Watts--I can give you a little background on him:

1) He apparently holds no university- or college-level degrees, meaning he's not been trained at a high level in either meteorology or climatology.

2) He is not AMS Certified, as some lists state, as that designation is only for AMS Certified Broadcast Meteorologists and Certified Consulting Meteorologists; Watts holds neither of those certifications.

3) He did hold the AMS 'Seal of Approval', a discontinued credential that the AMS gave to those not nolding a higher degree in atmospheric science or meteorology from an accredited college or university.

4) He initiated the "Surface Stations" project in an attempt to show that many of the weather stations the NOAA was using were situated in such a way that they would always return higher readings than actually existed. The project was a failure.

In short: Watts may have the best of intentions, and he may have a talent for broadcast weather...but a climatologist he is not.
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Poll time!

Q: In your opinion, what is the strongest Invest 90L will become in its lifetime.

A. It wont develop

B. Tropical Depression

C. Tropical Storm

D. Hurricane and/or Major Hurricane

No other letters, numbers, or symbols!!!
Member Since: Posts: Comments:

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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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