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 Levi32:
Good morning all.

Blog update.

Tropical Tidbit for Saturday, July 31st, with Video
Hey bud!
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Quoting 1900hurricane:

Except for Isadore and Lili, September 2002 was the same way. Here's the seasonal activity from 2007. I'd post 2002's as well, but I can't seem to find it anywhere.
2002
Storm: Dates: Max Winds: Min Pressure: Deaths: U.S. Landfall Category: Damage (millions US $):
Tropical Storm Arthur 07/14-07/19 60 992 0 No US Landfall 0
Tropical Storm Bertha 08/04-08/09 40 1008 0 TS 0
Tropical Storm Cristobal 08/05-08/08 50 999 0 No US Landfall 0
Tropical Storm Dolly 08/29-09/04 60 997 0 No US Landfall 0
Tropical Storm Edouard 09/01-09/06 65 1002 0 TS 0
Tropical Storm Fay 09/05-09/11 60 998 0 TS 5
Hurricane Gustav 09/08-09/15 100 960 0 TS 0.1
Tropical Storm Hanna 09/12-09/15 60 1001 3 TS 20
Hurricane Isidore 09/14-09/27 125 934 4 TS 330
Tropical Storm Josephine 09/17-09/19 60 1004 0 No US Landfall 0
Hurricane Kyle 09/20-10/12 85 980 4 TS 5
Hurricane Lili 09/21-10/04 145 940 12 1 860

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1639. IKE
Quoting sporteguy03:



Stay inside no time to mow the lawn today in Defuniak.


I always do it early...7:30-8am. This is just brutal.

Marianna...which is 50 miles east of me...already at 100 at the airport....all-time record highs may be achieved today...

Marianna, Florida (Airport)
Updated: 27 min 15 sec ago
Clear
100 °F
Clear
Humidity: 39%
Dew Point: 71 °F
Wind: 6 mph Variable
Pressure: 29.83 in (Steady)
Heat Index: 109 °F
Visibility: 10.0 miles
UV: 13 out of 16
Pollen: 3.60 out of 12
Pollen Forecast new!
Clouds:
Clear -
(Above Ground Level)
Elevation: 108 ft
Member Since: Posts: Comments:
So the gfs is verifying what I have been saying for the past 3 days 90l will come towards florida then the one after it follows it then we could have more in the gulf after or before. This is showing the upward mjo phase and the neg nao so that ridge will keep everything towards florida and the gulf this year. Correct if I'm wrong storm or mh09 but from what I learned from storm I could be correct oh and hollywood u r fine in here with us weather boys lol ;)
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Quoting Bordonaro:

Correct, however the current downward MJO is keeping TC development at bay, for the moment.

How long will this last?? O I am afraid that the "TC development is fixing to start hitting the fan"!!


Downward MJO's going away, the MDR is 2-4 mb below average for this time of year, plus with very high SST's the basin looks unaffected by downward MJO.



MJO so far has been following the UKMET's MJO prediction and takes it right back to octant 1 and 2 where the heat is favored.

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Quoting bwt1982:


So you are allowed to over hype a season but I cant have my opionon? LOL


Well obviously you're inserting your opinion by saying I am overhyping the season. You can have your opinion but please tell me why I am overhyping the season. Some evidence would be great.
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1635. bwt1982
Quoting sporteguy03:


Can you tell me why you think the season will continue to be inactive?

Nope, I never said inactive but I just dont think that we will see 8 named storms in Aug and cant see how people still think we will see more than 20 storms for 2010. But that is the nature of this blog to over hype things. Like last week with Bonnie and the predictions people had for her...LMAO
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Quoting OneDrop:
Wow, why so conflictive? And why attack someone with an insensitive comment like that? Weather and fishing go hand in hand!! BOYS? WOW!



lol nothing better to do I guess.... did you read the post about where I caught the red?
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Quoting mfaria101:

That was pretty offensive, the fact that many young people, male or female, attractive or not, choose to get involved in serious discussions like SOME that take place on this blog, gives me some hope for the future. Hell my daughter looks to be about hollywoods age, I can only hope she is as interested and apparently intelligent in her interests as hollywood appears to be.
And seriously, calling her a dude is really uncalled for, I dont think destinjeff is a cartoon....



Well boy, here's the deal, dudes have made fake profiles as girls on here before, so I was just calling out the possibility! lol

sheesh, get off my back a little lol.

I also just think its funny that guys on a weather blog flirt with girls they will never meet! It is quite the crackup you gotta admit!
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1632. Levi32
Good morning all.

Blog update.

Tropical Tidbit for Saturday, July 31st, with Video
Member Since: November 24, 2005 Posts: 635 Comments: 26701
Quoting BDAwx:
idk if this has been posted or not but.



GFS shows a tropical low/storm in the gulf of mexico Hurricane going up the east coast a hurricane in the Atlantic a strong tropical wave emerging off of africa.:O.

pretty scary stuff - this is 12th August.


Parade of storms.
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Quoting CybrTeddy:


Incorrect. SAL's not bad, and TUTT has pretty much lifted off the N and died off.

Correct, however the current downward MJO is keeping TC development at bay, for the moment.

How long will this last?? O I am afraid that the "TC development is fixing to start hitting the fan"!!
Member Since: Posts: Comments:
Quoting IKE:


Speaking of GW....my hometown....accurate PWS....from what I know of it....

WZEP AM 1460 DeFuniak Springs, FL, DeFuniak Springs, Florida (PWS)
Updated: 2 sec ago
Partly Cloudy
99.0 °F

Partly Cloudy
Humidity: 50%
Dew Point: 77 °F
Wind: 1.0 mph Variable
Wind Gust: 6.0 mph
Pressure: 29.80 in (Falling)
Heat Index: 115 °F
Visibility: 9.0 miles
UV: 12 out of 16
Pollen: 4.00 out of 12
Pollen Forecast new!
Clouds:
Few 4900 ft
(Above Ground Level)
Elevation: 174 ft



Stay inside no time to mow the lawn today in Defuniak.
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Quoting ho77yw00d:


Thanks, I am almost 29 and all I was doing was answering a question... geez some people are so uptight in this blog!


Its JFV paranoia. I think your who you say you are and I have no reason to contradict that fact.
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Quoting extreme236:
I stick by my prediction of 18-21 named storms. I can see various paths to getting this number.

6 in August, 6 in September, 3 in October, and just 1 in November or post-season would reach 18.


sounds reasonable. i averaged the totals of all the forecasts that dr. m posted about a month ago and it came out to 17, so i'm going with 17. that's my simple analysis - the average ;)
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Quoting extreme236:
People can call me a wishcaster for having such a high number, but they can't give me any solid evidence as to why my number is unreasonable. All they can say is how it has been "dead" so far...which means nothing in terms of the rest of the activity for the season.


Because they can't, and when they know all the evidence has contradicted there so called evidence they resort to name calling. There is no reason we shouldn't see at least 2007 style activity.
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Quoting mfaria101:

That was pretty offensive, the fact that many young people, male or female, attractive or not, choose to get involved in serious discussions like SOME that take place on this blog, gives me some hope for the future. Hell my daughter looks to be about hollywoods age, I can only hope she is as interested and apparently intelligent in her interests as hollywood appears to be.
And seriously, calling her a dude is really uncalled for, I dont think destinjeff is a cartoon....


Thanks, I am almost 29 and all I was doing was answering a question... geez some people are so uptight in this blog!
Member Since: Posts: Comments:
1624. BDAwx
idk if this has been posted or not but.



GFS shows a tropical low/storm in the gulf of mexico Hurricane going up the east coast a hurricane in the Atlantic a strong tropical wave emerging off of africa.:O.

pretty scary stuff - this is 12th August.
Member Since: Posts: Comments:
1623. IKE
Quoting KEEPEROFTHEGATE:
i can see the blog header
on dec 1st 2010
"WORLDWIDE HURRICANES KILLED OFF BY G.W.


Speaking of GW....my hometown....accurate PWS....from what I know of it....

WZEP AM 1460 DeFuniak Springs, FL, DeFuniak Springs, Florida (PWS)
Updated: 2 sec ago
Partly Cloudy
99.0 °F

Partly Cloudy
Humidity: 50%
Dew Point: 77 °F
Wind: 1.0 mph Variable
Wind Gust: 6.0 mph
Pressure: 29.80 in (Falling)
Heat Index: 115 °F
Visibility: 9.0 miles
UV: 12 out of 16
Pollen: 4.00 out of 12
Pollen Forecast new!
Clouds:
Few 4900 ft
(Above Ground Level)
Elevation: 174 ft
Member Since: Posts: Comments:
1622. bwt1982
Quoting extreme236:


Seasons are usually always dead until this month, I don't know where you get your history from. Clearly things are going to become very active.


So you are allowed to over hype a season but I cant have my opionon? LOL
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Quoting Bordonaro:

At the moment, we're being affected by the SAL layer, too many TUTT Lows in the wrong places, not necessarily high wind shear, just the typical June & July inhibiting factors for development we see almost every ATL Hurricane Season.

Then the typical Aug/Sept pattern develops, I pray and hope things do NOT got insane, however, most likely, they will!!


Incorrect. SAL's not bad, and TUTT has pretty much lifted off the N and died off.
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1620. xcool
by Crown Weather, the writer mentioned 12/13 storms between Aug. and Oct.
Member Since: September 26, 2009 Posts: 2 Comments: 15684
Quoting Bordonaro:

Then the typical Aug/Sept pattern develops, I pray and hope things do NOT got insane, however, most likely, they will!!


I want them 2 get active. This is boring. The "August/September pattern" that you mentioned, may last into October!
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Quoting KEEPEROFTHEGATE:
i can see the blog header
on dec 1st 2010
"WORLDWIDE HURRICANES KILLED OFF BY G.W.


Or "Aerosoles choke Atlantic"
Member Since: July 1, 2005 Posts: 10 Comments: 1683
ex-90L reminds me a lot of Hurricane Florence in 2006. Hopefully if it does develop it takes a similar path.
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1616. OneDrop
Quoting Jedkins01:
Hey to all the nerds, ho77lywood is probably a dude pretending to be a girl lol, even if shes not, this a weather blog not an online dating service, keep the focus on weather, boys, shall we? lolol
Wow, why so conflictive? And why attack someone with an insensitive comment like that? Weather and fishing go hand in hand!! BOYS? WOW!
Member Since: Posts: Comments:
Quoting KEEPEROFTHEGATE:
i can see the blog header
on dec 1st 2010
"WORLDWIDE HURRICANES KILLED OFF BY G.W.

At the moment, we're being affected by the SAL layer, too many TUTT Lows in the wrong places, not necessarily high wind shear, just the typical June & July inhibiting factors for development we see almost every ATL Hurricane Season.

Then the typical Aug/Sept pattern develops, I pray and hope things do NOT got insane, however, most likely, they will!!
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Quoting bwt1982:


LOL! your not talking about the Atlantic basin are you? 8 in August with the season being as dead as it is? LOL! enough wishcasting!


Can you tell me why you think the season will continue to be inactive?
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1613. Ossqss
Interesting read :)

Huge Hurricane Study Gears Up
Jul 30, 2010 10:26 AM ET


"A massive research project this summer may help reveal some of the storms' best-kept secrets. Researchers sponsored by three government agencies — NASA, the National Oceanic and Atmospheric Administration (NOAA), and the National Science Foundation (NSF), will swarm the skies of the tropical Atlantic Ocean with specially outfitted planes in an effort to better understand how — and why — tropical cyclones form in the first place."
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Quoting sporteguy03:

I agree completely it only takes a few days to get going not months or weeks last August there was 4 named storms in two weeks at the end of August.


Exactly. Things can get active very quickly, and once they do, I doubt we'll have much of a break.
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1609. DDR
Quoting DDR:

Hi slu
Are you serious?
you might want tocome here to escape the cape verde season.I'm not sure im 13 kilometres east of Port-of-Spain.
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Quoting surfswells100:
has a hurricane ever formed from 2 invests merging together?


Yes, Florence in 2006.
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Doesn't look half-bad...
Member Since: July 7, 2010 Posts: 0 Comments: 5725
1606. bwt1982
Quoting Neapolitan:


Stiock around, my child; you might just learn something.


Oh I will stick around, but not sure what I will learn from predictions like that! LOL!
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1604. Drakoen
The way it is looking on the models, I would be surprised if we do not get a tropical cyclone from ex-90L.
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Quoting extreme236:
I stick by my prediction of 18-21 named storms. I can see various paths to getting this number.

6 in August, 6 in September, 3 in October, and just 1 in November or post-season would reach 18.

I agree completely it only takes a few days to get going not months or weeks last August there was 4 named storms in two weeks at the end of August.
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Quoting extreme236:
People can call me a wishcaster for having such a high number, but they can't give me any solid evidence as to why my number is unreasonable. All they can say is how it has been "dead" so far...which means nothing in terms of the rest of the activity for the season.
That's what I say!
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Quoting Drakoen:


Which is exactly why we can't rule out this season. We've already had two named storms and it looks like the months ahead will be very active. I may lower my season totals come August but it won't be by much.


Exactly. I don't understand the thinking behind people who believe otherwise.
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has a hurricane ever formed from 2 invests merging together?
Member Since: Posts: Comments:
1599. KEEPEROFTHEGATE (Mod)
i can see the blog header
on dec 1st 2010
"WORLDWIDE HURRICANES KILLED OFF BY G.W."
Member Since: Posts: Comments:
1598. DDR
Quoting SLU:


Is it raining in Port of Spain?

I'll be coming to take up residence in Trinidad from late August.

Hi slu
Are you serious?
you might want tocome here to escape the cape verde season.I'm not sure im 13 kilometres east of Port-of-Spain.
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Quoting extreme236:


That number was actually tied in 2007, but those storms were rather weak.

Except for Isadore and Lili, September 2002 was the same way. Here's the seasonal activity from 2007. I'd post 2002's as well, but I can't seem to find it anywhere.

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Quoting bwt1982:
LOL! your not talking about the Atlantic basin are you? 8 in August with the season being as dead as it is? LOL! enough wishcasting!


Stiock around, my child; you might just learn something.
Member Since: Posts: Comments:
People can call me a wishcaster for having such a high number, but they can't give me any solid evidence as to why my number is unreasonable. All they can say is how it has been "dead" so far...which means nothing in terms of the rest of the activity for the season.
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Quoting Drakoen:


The convection needs to consoladate. Right now, it's just disorganized convection, but it's convection nonetheless.
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Quoting Hurricanes101:
16 days, yikes for PR and DR if that were to verify





That would be a utter disaster.
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Quoting bwt1982:


LOL! your not talking about the Atlantic basin are you? 8 in August with the season being as dead as it is? LOL! enough wishcasting!


Seasons are usually always dead until this month, I don't know where you get your history from. Clearly things are going to become very active.
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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