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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Good morning everyone -- nice to see pleasant conversations going. Have to say that I'm tired of the nonsense going on around here lately.

Storm: the area that we are watching with 90L, and the new wave behind it. This should be no different than watching a low pressure area trying to decide which point wants to become a coc, right? Basically what we are able to watch is the actual formation (or possible formation) of a system, and the actual mechanics of how it occurs.
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1239. aquak9
hi gamma, heat has been relentless. Like GetReal said years ago, the rains will come, but they'll come with a name.
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1238. aquak9
oh palm, did not recognize the name, sorry, are you palmyra punishment?

if so, then no offense meant.
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Quoting aquak9:
so until Christ is the one that posts these models i will take them with a grain of salt.

(spews coffee ALL OVER the keyboard)


Good morning Aqua,
been doing a lot of lurking here but not much posting.. but sometimes people here can say the darnest things! LOL

Good morning to all of you. Happy Saaturday!

I fully expected a busy season and predicted the first Hurricane for June 21st... boy was I off! but not really Alex became a hurricane before the end of June.... but July has been a bust except for the little excitment Bonnie brought to us here in South Fla.


my daughter is a senior life guard for the city and she is like "MOM what's up with this weather.. no summer afternoon thunderstorms to give us a break, no hurricane watches or warnings. just one day after another of extreme heat!" LOL And she h as been a life guard for almost 10 years...and really enjoyed all the "time off" in 2004 and 2005!

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Quoting Hibiscus07:
Hi All-
I've been reading Dr Masters' blog for several years and especially love the comments section (some for entertainment :P, but some have tons of great info!)

I have an MS in Atmospheric Science and although I took the required Met classes (synoptic, mesoscale, intro forecasting, etc.), my research focus was on the impacts of long-term natural climate variability (primarily PDO, PNA, NAO, and AMO) on water resource availability in the Northeastern US.

For the last 5 years, I've been a consultant (yes, the dreaded government contractor! haha) and in my group we specialize in climate change impacts and adaptation. We focus on many sectors, but I work mostly on impacts/adaptation for terrestrial/coastal ecosystems and transportation infrastructure.

I do almost no technical analysis at this point of my career (except a small amount of GHG inventory work), so some of the links and discussion here actually do keep my memory refreshed and help me learn about some aspects of tropical weather that I never knew much about in the first place.

Anyway, I know there's been some heated debate on here re: anthropogenic climate change, but I am going to try to refrain from any arguing (as long as I can hold my tongue :D)

I'm currently in my 7th month of pregnancy and am somewhat immobile right now, so have plenty of time to spend my evenings on this blog haha

Anyway, looking forward to chatting and learning more.

Hibiscus


Good morning everyone, and welcome Hibiscus07!
:)
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Well off to work.Have a blessed day everyone.
Member Since: June 6, 2010 Posts: 0 Comments: 853
Quoting Hibiscus07:
Hi All-
I've been reading Dr Masters' blog for several years and especially love the comments section (some for entertainment :P, but some have tons of great info!)

I have an MS in Atmospheric Science and although I took the required Met classes (synoptic, mesoscale, intro forecasting, etc.), my research focus was on the impacts of long-term natural climate variability (primarily PDO, PNA, NAO, and AMO) on water resource availability in the Northeastern US.

For the last 5 years, I've been a consultant (yes, the dreaded government contractor! haha) and in my group we specialize in climate change impacts and adaptation. We focus on many sectors, but I work mostly on impacts/adaptation for terrestrial/coastal ecosystems and transportation infrastructure.

I do almost no technical analysis at this point of my career (except a small amount of GHG inventory work), so some of the links and discussion here actually do keep my memory refreshed and help me learn about some aspects of tropical weather that I never knew much about in the first place.

Anyway, I know there's been some heated debate on here re: anthropogenic climate change, but I am going to try to refrain from any arguing (as long as I can hold my tongue :D)

I'm currently in my 7th month of pregnancy and am somewhat immobile right now, so have plenty of time to spend my evenings on this blog haha

Anyway, looking forward to chatting and learning more.

Hibiscus


Welcome.. and Congratulations.... get that rest for the little one... Sit back have a little debbie and enjoy the fun.. LOL (my wife and I have 4 kids)
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Good morning Storm.I see the wave has started to absorbe ex 90l.
Member Since: June 6, 2010 Posts: 0 Comments: 853
1230. palmpt
Quoting aquak9:
palmpt, that wasn't respectful at all to sainthurrifan. He's been here since before Katrina and has always offered a sense of humor and respect to everyone.

I'm just sayin'...


I have been here since day one myself and missed the humor. sorry. just sayin...
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Quoting wunderkidcayman:
hey Chicklit not sure about our drought problem but you see the clouds on the sat covering us but still I am on the northwestern side of grand cayman and not a single drop of rain just mostly cloudy-near overcast
None on the southeastern side either although it poured in town yesterday.
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Quoting aquak9:


no, that's the East Coast Men's Wrestling Federation


theres a TS coming off the top turnbuckle.... putting the east coast into a full nelson...
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1227. aquak9
palmpt, that wasn't respectful at all to sainthurrifan. He's been here since before Katrina and has always offered a sense of humor and respect to everyone.

I'm just sayin'...
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Hi All-
I've been reading Dr Masters' blog for several years and especially love the comments section (some for entertainment :P, but some have tons of great info!)

I have an MS in Atmospheric Science and although I took the required Met classes (synoptic, mesoscale, intro forecasting, etc.), my research focus was on the impacts of long-term natural climate variability (primarily PDO, PNA, NAO, and AMO) on water resource availability in the Northeastern US.

For the last 5 years, I've been a consultant (yes, the dreaded government contractor! haha) and in my group we specialize in climate change impacts and adaptation policy. We focus on many sectors, but I work mostly on impacts/adaptation for terrestrial/coastal ecosystems and transportation infrastructure.

I do almost no technical analysis at this point of my career (except a small amount of GHG inventory work), so some of the links and discussion here actually do keep my memory refreshed and help me learn about some aspects of tropical weather that I never knew much about in the first place.

Anyway, I know there's been some heated debate on here re: anthropogenic climate change, but I am going to try to refrain from any arguing (as long as I can hold my tongue :D)

I'm currently in my 7th month of pregnancy and am somewhat immobile right now, so have plenty of time to spend my evenings on this blog haha

Anyway, looking forward to chatting and learning more.

Hibiscus
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I understand storm certainly no hard feelings.And may God continue to richly bless you and your family have a great day.
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Quoting Chicklit:


Hi Storm Petrol, are you over your drought in the Caymans?
I am not him but this is what we have had. Decent amount in July . Rain So Far This Year 19.28 in.
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Good morning Aqua.
Member Since: June 6, 2010 Posts: 0 Comments: 853
1222. palmpt
Quoting StormW:


Well, maybe ya need to learn something about the atmosphere and global signals, cause obviously, you have no idea what all the signals are showing.. Everything you need to know is in my synopses for the past 4 days. Or better yet, if you're going to "mock" anything I say, then stay on Bob's blog.


About the only thing folks like sainthurrifan does is show how ridiculous they and how they don't get it. Hit the ignore button, Storm. And, by the way, good morning.
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1221. aquak9
Quoting portcharlotte:
I think Christ does the ECMWF model




no, that's the East Coast Men's Wrestling Federation
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Quoting deautschlandfutbol:
Where the heck is all the action storm I'm starting to look bad at work telling everybody that tropics are about to explode and they haven't yet I don't get it where is the mjo where is the neg nao the positive soi.


maybe you should rent a movie lol.
Member Since: July 11, 2006 Posts: 14 Comments: 11348
Where the heck is all the action storm I'm starting to look bad at work telling everybody that tropics are about to explode and they haven't yet I don't get it where is the mjo where is the neg nao the positive soi.
Member Since: June 20, 2010 Posts: 0 Comments: 73
I think Christ does the ECMWF model


Quoting aquak9:
so until Christ is the one that posts these models i will take them with a grain of salt.

(spews coffee ALL OVER the keyboard)
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1216. aquak9
so until Christ is the one that posts these models i will take them with a grain of salt.

(spews coffee ALL OVER the keyboard)
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Well put! No one wants disaster....but hurricanes are a way of life, without them our atmosphere can not function as far as the transfer of heat...


Quoting P451:


Agreed.

Some people get torn up on here for no good reason just because they speak about a storm in a way that is wrongly perceived as wishing for people to get hurt.

I've seen a couple of valuable posters get such a response and it has forced them to stop posting and that's not right.

I'm not hoping I get a thunderstorm that destroys my neighbor's house but I am hoping for a really strong storm to blow through.

It's interesting. That is all it is.

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1214. aquak9
g'morning P451.

During '05, it all happened so fast...I'd be gone from the computer for ten hours, try to catch up, and end up with hot and cold chills and a belly ache. NO WAY do I wanna watch that kinda foolishness again.
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anyway I am going for my breakfast be back in 1-2 hours and the I will check back on ex-90/pre91L sat
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Quoting aquak9:
hiya d'fly! Yikes another oppressively hot day on store for us across the southeast.

and a belated g'morning to granny as well.


I know... I looked outside at the mower and I started started to sweat...




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Quoting sailingallover:
90L will like Bonnie and Schwarzenegger will be back in about 3 days....

Sometimes Trolls take pics of other people and post them in fake profiles..

Who posted a fake picture sailing?
Member Since: June 6, 2010 Posts: 0 Comments: 853
1210. Hhunter
people forget when most activity actually is its after heat builds up first part of summer..hurricane season 101
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1208. KEEPEROFTHEGATE (Mod)
let me express
iam not writing off the season i for one have very high expectations just like everyone and still do but no matter what we say is going to happen or not happen in the end numbers don't lie and yes CT come the end of august we should be up to storm 6 or 7 name storms then another 5 or 6 in sept with 3 or 4 oct and 1 or 2 in nov thats a total of 10 to 13 plus what we already have for a grand total of 15 or 16
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Quoting wunderkidcayman:
hey Chicklit not sure about our drought problem but you see the clouds on the sat covering us but still I am on the northwestern side of grand cayman and not a single drop of rain just mostly cloudy-near overcast

Hi Wunderkid, yeah. Good for tourism though, isn't it?
Seems like mostly everything thus far has been south and west of you this year.
Member Since: July 11, 2006 Posts: 14 Comments: 11348
Sorry you feel that way storm it was meant to be a little humour for i have the upmost respect for your service to our country.But you do have to admit models parameters schematics are what they are. They were devised by man, man is not perfect.And i know your a man of faith so until Christ is the one that posts these models i will take them with a grain of salt.The only problem i have with you is you never talk about the other alternative just the ones you read,And yes i do like Bob for he is realist and does not worry if what he says is not what the teenies want to hear.But in closing you have my upmost respect but until the models come from Christ i will look at picture in front of me good day and God bless
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hey Chicklit not sure about our drought problem but you see the clouds on the sat covering us but still I am on the northwestern side of grand cayman and not a single drop of rain just mostly cloudy-near overcast
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Hey, I am going to tell you guys something...
Weather enthusiasts and meteorolgists would never have an interest in weather if it was always fair weather. Storms are what create an interest. If the weather was always perfect it would be a bore. These wishcasters are just people who love to watch the weather change and track storms..Nothing wrong with that. i experienced my first hurricane in 1964 in w. palm beach, Florida at the age of 11. I became hooked and it led to a 14 year career with the National Wx Sevice as a Met. Tech in West Palm and Miami.


Quoting SQUAWK:


Ike is not a "downcaster." He is an optimist. He is usually hoping for good weather and a good outcome. Unlike the ones that wish for a disaster. Those are the ones I would classify as "downcasters."
Quoting SQUAWK:


Ike is not a "downcaster." He is an optimist. He is usually hoping for good weather and a good outcome. Unlike the ones that wish for a disaster. Those are the ones I would classify as "downcasters."
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1202. aquak9
hiya d'fly! Yikes another oppressively hot day on store for us across the southeast.

and a belated g'morning to granny as well.
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Quoting msgambler:
Morning earthly


Morning
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Quoting KEEPEROFTHEGATE:
we are having problems getting systems going i don't know what it is but there are issues that were unforseen by even the experts this coming week will be the first of the droppin numbers game iam sure


If we knew all of the parameters, and how they interact with each other we would have seasonal forecasts that would demonstrate skill. We don't.
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Sorry double post!
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Quoting TankHead93:
One can clearly see the effect of the battle between now ex-90L and the newer wave behind it. The 850mb vorticity of ex-90L is now being transferred over to the new wave, the new wave is winning the battle and will take over, over the next couple of days. Click on the link and follow what I stated by clicking on past vorticity maps. (left hand side of link page) Link
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Quoting CybrTeddy:


I didn't say that. I said if August (which is unlikely to say the least) has no storms that this season will be 7-8 named. I highly doubt that will happen, as 2009 with high shear, lower SSTs, lower TCHP pulled out 4. We should be able to pull out 4, we'd be a 6 going into September

Oh okay i was wondering if that was what u meant. I think SAL is giving us some problems what do you think?
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Quoting KEEPEROFTHEGATE:
we are having problems getting systems going i don't know what it is but there are issues that were unforseen by even the experts this coming week will be the first of the droppin numbers game iam sure


This season has proven once they get going..

They get going.
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Morning earthly
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Quoting TankHead93:
What are some thoughts on this?
I need to know if I am correct on my observation, feedback would be nice and greatly appreciated. ;)
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This entire area looks just interesting to me.

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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.