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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have to say ive been watching that one off the east coast also sometimes you just never know , and sitting up here in souther new england know we are well over due up here
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Quoting Chicklit:
Everyone in Alaska is paid off by the oil companies. So global warming due to carbon emissions is not a popular idea up there.
I don't believe it's popular with Palin, either.
Nor was it popular with Bush, from another oily state, Texas.


HMMMMMM or with Clinton... this information was available to him as well... You neglected to mention him... HMMMmm.. Wake up folks.. it is ALL OF THEM! Like it or not!! They are all on the take in DC period.. They love to divide and conquer.... So many brainy people in here but still think it is one party against another... So silly....

It is us against them period. United we stand!
Member Since: July 1, 2005 Posts: 10 Comments: 1683
Quoting Chicklit:

No, dead sea plankton due to heat and dead trees and plants due to frost mean net minus zero.


Then don't apply the laws of equal and opposite reaction to it. It was a flawed statement.
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Quoting Bordonaro:

Ninety-nine degrees in Dallas-Ft Worth, TX is actually "pleasant", as dew points drop from 72F in the AM to 60-62F by 5PM, usually with a hot, dry SW breeze at 10MPH. Tolerable..

Ninety-nine in FL is "torture", with heat indices making a run on 115-120F!!


We've had more record low temperatures in Florida here this year than I can ever remember.
It's almost a daily thing now.
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MIMIC shows rotation starting to form off the east coast and the tropical wave off Africa.



Some 850 mb vorticity on disturbance of East Coast


Good Divergence


Not much convergence


Shear's 10 knots.
Member Since: July 8, 2005 Posts: 259 Comments: 24574
Quoting HurricaneSwirl:
So, Levi, I guess this type of situation would be extremely unlikely this winter?



Was unlike anything I've ever seen. Would love to experience it again. However I would not want to see all of those crops destroyed again.


This year and next year will be La Nina years, so yeah, thats pretty much not happening, although there is always a possibility..
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430. xcool
jasoniscoolman2010x HOW MANYTIME
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Quoting Levi32:


Net change is zero no matter how extreme the extremes are, according to the equal and opposite reaction thing you said. -1 and 1 average zero.....-1000000 and 1000000 average zero.

No, dead sea plankton due to heat and dead trees and plants due to frost mean net minus zero.
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Quoting CybrTeddy:
IR shot of the area off the US coast.


That area NW of the Bahama's keeps flaring up.
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So, Levi, I guess this type of situation would be extremely unlikely this winter?



Was unlike anything I've ever seen. Would love to experience it again. However I would not want to see all of those crops destroyed again.
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Quoting CybrTeddy:
IR shot of the area off the US coast.



looks like it is still attached to that trof
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422. xcool
TROPICAL WAVE IS EMBEDDED IN THE ITCZ APPROACHING THE CAPE VERDE
ISLANDS ALONG 21W S OF 18N MOVING W NEAR 10-15 KT. THIS WAVE IS
EMBEDDED WITHIN AN AREA OF A HIGH AMPLITUDE MOISTURE MAXIMUM. A
WELL DEFINED LOW TO MID LEVEL CYCLONIC FLOW SURROUNDS THE WAVE
AXIS EVIDENT ON INFRA RED SATELLITE DATA. SCATTERED MODERATE
CONVECTION IS WITHIN 35 NM ON EITHER SIDE OF THE WAVE AXIS NORTH
OF 12N. THE REST OF THE CONVECTION SOUTH OF 12N IS ASSOCIATED
WITH THE ITCZ.



THE ITCZ AXIS IS ANALYZED FROM THE WESTERN AFRICAN COAST OF
SENEGAL NEAR 14N17W...WESTWARD ALONG 10N25W 8N30W 9N40W 8N50W
12N60W...CONTINUING ACROSS NORTHERN SOUTH AMERICA. A 1010 MB
SURFACE LOW IS EMBEDDED IN THE ITCZ NEAR 9N33W. CLUSTERS OF
SCATTERED MODERATE TO STRONG CONVECTION ARE FROM 7N TO 13N
BETWEEN 20W AND 31W AND FROM 10N TO 16N BETWEEN 57 AND 61W
INCLUDING THE LESSER ANTILLES SOUTH OF 15N. SMALL CLUSTERS OF
SCATTERED MODERATE CONVECTION DOT THE AREA FROM 2N TO 10N
BETWEEN 35W AND 48W.

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I'm glad your post referred to "Nature" as just a "journal." It is certainly not a scientific journal anymore.

It seems that "American Scientist" is the only publication still in existence that has not been politically co-opted.

Very sad.

On 90L, it appears certain that it will be driven from existence by its follower wave - which bears watching.
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Everyone in Alaska is paid off by the oil companies. So global warming due to carbon emissions is not a popular idea up there.
I don't believe it's popular with Palin, either.
Nor was it popular with Bush, from another oily state, Texas.
Member Since: Posts: Comments:
416. xcool



RAINFALL.



XCOOL
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IR shot of the area off the US coast.

Member Since: July 8, 2005 Posts: 259 Comments: 24574
Quoting Chicklit:
It was 99 degrees on my car thermometer today in Ft. Lauderdale area. Thankfully, there were some clouds moving in and it rained at least in some areas. One thing I did note driving down last night was as I was in the wetland portions, it was about one degree cooler than when I passed through the asphalted and populated areas.

Ninety-nine degrees in Dallas-Ft Worth, TX is actually "pleasant", as dew points drop from 72F in the AM to 60-62F by 5PM, usually with a hot, dry SW breeze at 10MPH. Tolerable..

Ninety-nine in FL is "torture", with heat indices making a run on 115-120F!!
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the storm off the se coast will get swept away by a troff. 90 l will head towards fl then the gulf if everything stays the same right now but as we all know things will change almost every day during hurricane season.
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Quoting Bordonaro:

A breath taking 99F, dewpoint near 63F, Heat Index about 101F, a SW breeze at 10MPH.

Another "oven=like" day, with 7 days of 78-81F to 99-104F temps> Normal N TX Summer!!

Yes, seems to be hot everywhere. Glad to see ya on here.
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I'm not going here again tonight.

Invest 90L floater shows convection slowly increasing again in the overall area.
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I'm kind of surprised they didn't mention the low off the US coast. Blowing up convection and has been sustaining. I recall the ECMWF forecasting a low to develop here but never stuck to it.

GOES-E Satellite loop
Member Since: July 8, 2005 Posts: 259 Comments: 24574
Quoting Jeff9641:


I know and then I think you know it's just a blog. I have to much to worry about at work then to worry about people think on me on here. Thanks Buddy!

Yeah you said it all, I like to come in here and maybe learn a thing or to but as you said its nothing to get all worked up over. Take care and try to stay (kool)
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Quoting Chicklit:

That's false, actually.
Extremes beget extremes is a better way to put it. It doesn't balance because there is destruction involved with both extremes.


Net change is zero no matter how extreme the extremes are, according to the equal and opposite reaction thing you said. -1 and 1 average zero.....-1000000 and 1000000 average zero.
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I was also wondering about Kman, I have not seen him post anything personally in at least two weeks. He always had a good eye for picking out very minor features/MLC's etc. I really liked how he proposed observations he had made as well. I hope the GW debate has not driven him off for good.

I can not seem to get the Austin powers theme song out of my head... oh behave....
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Quoting JFLORIDA:


Actually I am still waiting for supporting literature on the PDO forecasts posted last night here form Levi.

What do you mean? Literature that shows we are headed towards a cold PDO or something else?
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It was 99 degrees on my car thermometer today in Ft. Lauderdale area. Thankfully, there were some clouds moving in and it rained at least in some areas. One thing I did note driving down last night was as I was in the wetland portions, it was about one degree cooler than when I passed through the asphalted and populated areas.
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Quoting KEEPEROFTHEGATE:


maybe i will take a break from the blogs this winter


lol


Now to convince SWMBO it is both of yours fault......
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Finally got decent rain on the East Coast......
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Quoting Levi32:


Equal and opposite gives a mean change of zero....hmm.

That's false, actually.
Extremes beget extremes is a better way to put it. It doesn't balance because there is destruction involved with both extremes.
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Quoting severstorm:

Hey how are you doing today? weather 87 here in z-hills fl.

A breath taking 99F, dewpoint near 63F, Heat Index about 101F, a SW breeze at 10MPH.

Another "oven=like" day, with 7 days of 78-81F to 99-104F temps> Normal N TX Summer!!
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Quoting nrtiwlnvragn:


Funny what goes around comes around. If that verifies some bloggers are going to have a lot of fun this winter.


maybe i will take a break from the blogs this winter


lol
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look like that new wave is eating up 90L
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Quoting alaina1085:
Hey guys, where has kman been? I havent seen him post in a while. Always look forward to his input.
I was wondering about that earlier today.
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Quoting Chicklit:
Extremes bring about extremes Levi. For every action there is an equal and opposite reaction.


Equal and opposite gives a mean change of zero....hmm.
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392. xcool
warmest winter 2011 here in LA .
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Quoting KEEPEROFTHEGATE:
lots of snow and cold for the big fish cruel levi very cruel


Funny what goes around comes around. If that verifies some bloggers are going to have a lot of fun this winter.
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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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