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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1491. bappit
Quoting Orcasystems:


Ahhhhh now there is the first problem in your theory. Your making the assumption that all of the people on here think. We know from many previous experiences, that is not necessarily true :)

Excellent point.
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Quoting texwarhawk:


You know those storm lines we get here in tornado alley with 60+ mph winds. Unless your close to the eye of a major its a lot like that only the storm line lasts a couple hrs. Can be frightning at night but during the day its amazing/intense. But then again I love the intensity of severe weather.


yeah but they can last for hours from what i am told while one of those storms gets over fast
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#1467 cute
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1487. bappit
Satellite and In Situ Equatorially-Trapped Waves

For at least 40 years, researchers have fully appreciated that the vanishing of the Coriolis %u2018force%u2019 at the equator causes the near-equatorial regions to act as a waveguide for atmospheric and oceanic waves with frequencies low enough to be affected by the Earth%u2019s rotation. Waves in the equatorial waveguide tend to propagate in the east-west direction and are organized into a discrete set of north-south %u2018modes%u2019 with coherent variability spanning a distance of more than 1500 km across the equator.

So a "trapped equatorial mode" would be something along the lines of a wave traveling in the equatorial waveguide as opposed to a wave in the easterlies. Maybe they make the ITCZ undulate. [Edited out some nonsense.]
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Quoting Drakoen:
GFS 12z also looks to develop 90L and takes it towards the northern Lesser Antilles.


Finally it actually develops it. SW Caribbean cyclone is interesting.
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Quoting OneDrop:
Hollywood, looks look T storms already building here in northeast broward, how is it down by southeast broward


nice cuda by the way I just ate my 20 inch red for lunch... so good.... :)
Member Since: July 3, 2010 Posts: 0 Comments: 427
Quoting FloridaHeat:



thank you i am just here to learn i am from oklahoma so i have never seen a storm in my life my new neighbor in florida says hurricanes are bad here so i want to be prepared.


You know those storm lines we get here in tornado alley with 60+ mph winds. Unless your close to the eye of a major its a lot like that only the storm line lasts a couple hrs. Can be frightning at night but during the day its amazing/intense. But then again I love the intensity of severe weather.
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Can anyone believe that there is an area that has a 20% chance of development over the next 48 hours in the Caribbean? There's barely a cloud. That will probably be dropped off the TWO later.
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Quoting Neapolitan:
I love it Bring it don't sing it!
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Quoting OneDrop:
Hollywood, looks look T storms already building here in northeast broward, how is it down by southeast broward


here in lee county it has been raining on and off cells pop up then poof they are gone.. it is overcast and yucky (another day in paradise) lol rains just enough for that heat and humidity...lol
Member Since: July 3, 2010 Posts: 0 Comments: 427
Man, that new-wave is pretty close to 90L.
I assume it is too early to tell which one is moving faster to the W.
That is... if 90L is slightly faster... it might free itself from destruction.
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1478. Drakoen
GFS 12z also looks to develop 90L and takes it towards the northern Lesser Antilles.
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1477. 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 15:45:01Z

2010 Storms
All Active Year


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

Southern Hemisphere
Member Since: July 15, 2006 Posts: 189 Comments: 59031
Quoting CanesfanatUT:


My Momma and brother are moving from there today.


Interesting group of people there.

Don't think I would want to be there in Sept.
Member Since: October 1, 2007 Posts: 81 Comments: 26516
Afternoon StSimons!
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Quoting TropicalAnalystwx13:


Click on your current avatar.

Then upload a picture.

When it gets approved...Click on it.

Scroll down on the right side of the page and you should see "Make this my primary portrit"

And all done...I think


thank you i am just here to learn i am from oklahoma so i have never seen a storm in my life my new neighbor in florida says hurricanes are bad here so i want to be prepared
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1470. Drakoen
GFS 12z looks to form a cyclone in the southwestern Caribbean that moves into central America.
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Quoting Orcasystems:
Anyone here from Gainesville?


My Momma and brother are moving from there today.
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1468. Drakoen
Quoting Snowlover123:


Hi Drak,

I'm 14, so I'm stll trying to get to terms with all of the weather and Tropical Related stuff, so what is your expert analysis on this disturbance. You think that things are coming together? How so?


Read post 1430
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Quoting Mother Nature:


I don't comment in this forum very often, what with me being so busy and all, but I
do stop by from time to time to catch up on what folks are saying about me...and lately what some have been saying isn't very nice. I've been called a tease here. I've been called boring. I've been called a bust...and all because I haven't taken the time to let loose the way some here seem to want me to just so they can enjoy a little mid-summer entertainment.

Well, boo-hoo.

First, it's not my job to keep you folks entertained. That's what television--
Jersey Shore reruns, anyone?--is for. And if you don't have cable, go to an amusement park. Or a baseball game. Or the local park. Or the beach (except the ones caked with tarballs...which, by the way, are not my fault). Do something. Do anything. But just--please--stop sitting around here complaining that I'm not making things fun enough for you.

Second--and more importantly--in case you guys haven't been paying attention, I've been a little busy elsewhere as of late. I mean,
very busy. I've been trying to fry half the people in Europe and Africa, while attempting to freeze folks in South America. I've created hundreds of tornadoes and severe thunderstorms. I've made dust storms and heat waves, earthquakes and blizzards, Chinese typhoons and California wildfires...and just yesterday I killed a thousand Pakistanis with a flood.

What more do you guys want from me?!

Okay, that question was rhetorical. I know what you want, all you
X-casters here: a hurricane. Or two. Or, you know, thirty. You want 2005 all over again, or 1995, or even 2004. Heck, you'd probably be happy with another 1969 (and that was a hoot, let me tell you). Well, I hear you. And as the calendar flips over to August tomorrow, I can promise you that I'm not finished with this year. Heck, I haven't even started yet; these things take a while to set up, you know. I've been letting both the Caribbean and the Gulf of Mexico simmer for months. I've been cutting back on the shear. I've been setting up the atmosphere in a storm-optimal configuration. And any day now--that is, when I feel like it--I'll start the show. I'll start it just for you guys. And by the time I'm involved full time with the coming winter's cold snaps and major snow events, you'll be asking yourselves just what in the world were you thinking while complaining about me.

I'm a tease, am I? I'm boring? I'm a bust?

Okay, then. Fine. Prepare to be "entertained". And don't say you weren't warned...

};-)>
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Quoting Drakoen:
Things are finally beginning to take shape with our disturbance.


Hi Drak,

I'm 14, so I'm stll trying to get to terms with all of the weather and Tropical Related stuff, so what is your expert analysis on this disturbance. You think that things are coming together? How so?
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1465. Drakoen
Quoting Tropicsweatherpr:
Drakoen, they may reactivate 90L again and have 91L for the wave behind, what do you think about that possibility?


It looks like 90L is the dominant feature at the moment. There's some obvious broad rotation with the system. They should reactivate it or possibly tag it invest 91L.
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Quoting FloridaHeat:
i give up i cant figure this out my avatar is not showing no matter what


Click on your current avatar.

Then upload a picture.

When it gets approved...Click on it.

Scroll down on the right side of the page and you should see "Make this my primary portrit"

And all done...I think
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Quoting Tropicsweatherpr:
Drakoen, they may reactivate 90L again and have 91L for the wave behind, what do you think about that possibility?


I'm not Drak, but I think they would designate it 91L.
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okay, i'm back!

Quoting superweatherman:
This Hurricane season they are going to be:
A.10-14 storms
B.14-18 storms
C.18-22 storms
D. Over 22 name storms


A
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1461. Drakoen
Things are finally beginning to take shape with our disturbance.
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Nothing to track out there? What does the ecmwf show today?
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Drakoen, they may reactivate 90L again and have 91L for the wave behind, what do you think about that possibility?
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Quoting FloridaHeat:
i give up i cant figure this out my avatar is not showing no matter what


Your new and unknown... your picture has to be "approved" before they will let you use it.
Member Since: October 1, 2007 Posts: 81 Comments: 26516
1457. Ossqss
This is a pretty cool tool for future use :)

Click the picture to access the interactive model tool.



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Quoting FloridaHeat:
i just moved to fl and my neighbor has me all freaked about hurricanes so i did research and found this website
Don't get freaked. This is the place for GOOD information. Pay attention and be as prepared as possible. Also make sure you have a back-up plan in case of evacuations. Where in Florida ?
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Quoting CybrTeddy:


Looks interesting. Surface pressures in the area are 1009-1011 mbs.


I'd be pretty surprised if we did not get a tropical cyclone to form from this.
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Quoting Drakoen:
Definitely looks ominous and the models are showing everything trying to congeal with the around the surface trough axis near 35W.



Looks interesting. Surface pressures in the area are 1009-1011 mbs.
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Anyone here from Gainesville?
Member Since: October 1, 2007 Posts: 81 Comments: 26516
Quoting Drakoen:
Definitely looks ominous and the models are showing everything trying to congeal with the around the surface trough axis near 35W.



Lots of energy out there!
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i give up i cant figure this out my avatar is not showing no matter what
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I believe a circulation will spin up/tighten up between 34 and 35 W longitude.
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1449. Drakoen
Definitely looks ominous and the models are showing everything trying to congeal with the around the surface trough axis near 35W.

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Quoting superweatherman:

Hey.. I just want to know what people think so far..


Ahhhhh now there is the first problem in your theory. Your making the assumption that all of the people on here think. We know from many previous experiences, that is not necessarily true :)
Member Since: October 1, 2007 Posts: 81 Comments: 26516
1447. Ossqss
Click to enlarge



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Quoting Drakoen:


That's what I am seeing on RGB imagery as well. Looks like a broad area of low pressure. Convection is flowing cyclonic towards the surface trough axis. It still appears that the two disturbances have yet to phase.


Wow! I actually am seeing it right!
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Quoting superweatherman:

You think this season is going to be a bust?

Boo!!!!
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Quoting MrMarcus:


What comes before A?

You think this season is going to be a bust?
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Quoting msgambler:
I really never know where to start...LOL


Thats my plan... keep them guessing :)
Member Since: October 1, 2007 Posts: 81 Comments: 26516
Quoting FloridaHeat:
i am new to the blog and dont know how to do an avatar

Same here and I sent in my photo so many times..I don't know what I am doing wrong? Maybe it will show up now????
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Quoting msgambler:
YAY, another worthless poll

Hey.. I just want to know what people think so far..
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Dr. Masters co-founded wunderground in 1995. He flew with the NOAA Hurricane Hunters from 1986-1990. Co-blogging with him: Bob Henson, @bhensonweather

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