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 aquak9:
cute video, CoolJason. Too bad the storms don't have 100 miles of desert to travel thru.


Looking at the SAL- they might
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Quoting aquak9:
it's called "tartin' and twinkin' " by the oldtimers.

stay on the blog so long, chain the kids to the kitchen table, only feed'm poptarts and twinkies.

That's all in humor folks!! no bashing!!


I remember that!!!!!! from 2005!!!
Poptarts, the breakfast of kids when your parents are blogging on WU!
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Quoting Patrap:
No Model runs have been done on the er,.."thingee" since 18Z yesterday.


CMC.... is still on the "day after Tomorrow" forecast

Nogaps.... Is Blobby blobby everywhere forecast

GFS....... Is on still using Vista and waiting to switch to Windows 7.
Member Since: July 1, 2005 Posts: 10 Comments: 1683
There still appears to be a low at about 7N 31W.

Link
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1286. Dakster
Quoting earthlydragonfly:


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






Yeah. I know. I thought about mowing the grass and almost passed out from heat exhaustion.

Feels like another triple digit heat index.

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1285. aquak9
cute video, CoolJason. Too bad the storms don't have 100 miles of desert to travel thru.
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1284. SLU
HIRES

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1283. Patrap
Quoting CybrTeddy:


You stare at stuff long enough and you start developing what you would say 'psychic' abilities. I call it insanity. How you doing this am Pat?


Swimming in Coffee and Biscuits with Jelly..

jelly is sticky stuff,no matta the amount of napkins
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1282. Zegama
Water Vapor shows the Saharan dust dipping into the wave/blob area.
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Not Ron Magill - reference is to the state of my household - not where I work. LOL

I had the name before they changed theirs.
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Quoting Patrap:
A what..?

Man..some psychic abilities are noted this am.

LOL


You stare at stuff long enough and you start developing what you would say 'psychic' abilities. I call it insanity. How you doing this am Pat?
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1278. aquak9
it's called "tartin' and twinkin' " by the oldtimers.

stay on the blog so long, chain the kids to the kitchen table, only feed'm poptarts and twinkies.

That's all in humor folks!! no bashing!!
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1277. KEEPEROFTHEGATE (Mod)

NMFC Norfolk Tropical Feed
No Active Tropical Warnings in the Atlantic, Caribbean, or Gulf of Mexico
By Maritime.CDO@navy.mil (NMFC CDO) from Naval Maritime Forecast Center Norfolk Virginia. Published on .

As of Sat 31 Jul 2010 14:00:02Z

2010 Storms
All Active Year


Atlantic
NONE
East Pacific
97E.INVEST
Central Pacific
92C.INVEST
West Pacific
94W.INVEST
95W.INVEST
Indian Ocean

Southern Hemisphere
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1276. SLU
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1275. KEEPEROFTHEGATE (Mod)
Quoting Patrap:
No Model runs have been done on the er,.."thingee" since 18Z yesterday.
90L has been deactivated we wait for 91L
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Quoting Zegama:
Good Morning All! It seems that the Navy/NRL site has dropped 90L from their active list.Link


The system has been absorbed and is now part of a entirely different system, might see 91L soon.
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Quoting aquak9:
oh no, d'fly, it's not the coriolis effect...it's the "I been staring at this thing for 22 hours straight" effect...

everything starts to spin clockwise by then! :)


lol
Member Since: July 1, 2005 Posts: 10 Comments: 1683
1272. SLU
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1271. aquak9
oh no, d'fly, it's not the coriolis effect...it's the "I been staring at this thing for 22 hours straight" effect...

everything starts to spin clockwise by then! :)
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1270. Patrap
No Model runs have been done on the er,.."thingee" since 18Z yesterday.
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1268. Zegama
Good Morning All! It seems that the Navy/NRL site has dropped 90L from their active list.Link
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Quoting aquak9:


if you stare at them long enough, they all seem to spin clockwise...


That would be the Coriolis effect water puppy!! lol the further north you are the greater the spin
Member Since: July 1, 2005 Posts: 10 Comments: 1683
1266. Patrap
A what..?

Man..some psychic abilities are noted this am.

LOL
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Quoting Neapolitan:
Looking rather perky in a blobbish sort of way this morning, no?

Colin? Danielle? Bueller? Bueller? Bueller?


Looks like it might be trying to pull a 92L and pull together in the ITCZ.
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Quoting FLWeatherFreak91:
From the still image it looks like it's rotating clockwise lol.


lol anti-cyclonic hurricane. Its like an anti-cyclonic tornado only bigger!
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1263. aquak9
Quoting FLWeatherFreak91:
From the still image it looks like it's rotating clockwise lol.


if you stare at them long enough, they all seem to spin clockwise...
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1262. msphar
Six weeks to the midpoint of the season.
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Quoting zoomiami:
The monsoonal process here in the Atlantic is something new. My understanding of this is that a large area cooks itself down, vs. what we normally watch which is a smaller area where the circulation works it way down, and then begins to grow.

is this Ron Magill?
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Quoting Neapolitan:
Looking rather perky in a blobbish sort of way this morning, no?

Colin? Danielle? Bueller? Bueller? Bueller?


I think that is showing organization..
Member Since: July 1, 2005 Posts: 10 Comments: 1683
Quoting SAINTHURRIFAN:
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


??? whadda,.... oy vey... really
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Looking rather perky in a blobbish sort of way this morning, no?

Colin? Danielle? Bueller? Bueller? Bueller?
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1256. Patrap
Floater - Rainbow Color Infrared Loop
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Quoting CybrTeddy:
This entire area looks just interesting to me.

From the still image it looks like it's rotating clockwise lol.
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1254. Patrap
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Nothing much happening anywhere... this is a Good thing :)



AOI

AOI

AOI

AOI

AOI

TS BUSTED FORECAST ALIBI
Member Since: October 1, 2007 Posts: 81 Comments: 26511
Hey Aqua -- second cup for me! My son says that you all have had some really hot weather up there. He just came home for a few weeks before classes start.

I completely agree - every time someone looks at the area and it hasn't formed into a storm, they will say its dead. My thinking is that until it gets towards the Antilles its just going to dither along.
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1250. DVG
Quoting Chicklit:
Hi StormW. Funny the arguments people have on here, isn't it. As if this were a movie and everything should start happening as you sit in your seat in front of the computer.


It will probably be an interesting study, and likely someone's thesis someday on how people communicate with one another has changed due to technology.

I do my own stock trading, and between politcal bogs, stock bogs, and here, I will tell you the way in which I react has been tempered over time.

I think there is some maturing process at work as society becomes more sophisticated about the abundance of information, manipulation, and instigation that goes on.

Also interesting is the developement of relationships.
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Nice to see you all this morning - off to do Saturday chores.
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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


I agree. You may see some drop their numbers--a little. One of the most obvious unforeseen variables was the strength of the on coming La Nina. In addition, this represents a dramatic reversal of one of the globes main weather drivers which can lead to unexpected results. The center of the high in the Atlantic has remained strong and broad pressing south in the Central Atlantic increasing subsidence and dry air which has helped suppress development. This will change naturally as the season progresses and allow the normal uptick in activity timing wise but with very favorable environmental factors in place. A very active season is still likely.
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1247. aquak9
g'morning zoo! (lifts coffee cup to the south) this is gonna be a long one to watch, it'll get declared dead 3 times, and relocate itself half a dozen times. That is, after it decides to create a true COC, which could take another 3-5 days.

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Quoting KEEPEROFTHEGATE:
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


I'm still standing by my long-held prediction: 20/12/6 (7 or 8 in August, 6 or 7 in September, 4 or 5 in October, maybe even a straggler or two in November/December). All the pieces are there...
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The monsoonal process here in the Atlantic is something new. My understanding of this is that a large area cooks itself down, vs. what we normally watch which is a smaller area where the circulation works it way down, and then begins to grow.
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1244. Patrap


Tropical Video Update

Posted on July 30, 2010 at 2:30 PM

Updated yesterday at 8:17 PM
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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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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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