Little change to 90L; new African tropical wave is worth watching

By: Dr. Jeff Masters , 8:53 PM GMT on July 30, 2010

Share this Blog
3
+

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

Reader Comments

Comments will take a few seconds to appear.

Post Your Comments

Please sign in to post comments.

or Join

Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 1141 - 1091

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35Blog Index

1141. IKE
Quoting clwstmchasr:
Doesn't it seem like since about mid-June we keep thinking that in about 10-14 days things are going to really explode? I was convinced that we were going to have an early July Cape Verde storm. Now here were are one day from Aug 1st and the feeling is that we're a week to 10 days away from the tropics exploding.


You're exactly correct.

My motto the rest of 2010...I'll believe it when I see it.
Member Since: Posts: Comments:
Quoting clwstmchasr:
Doesn't it seem like since about mid-June we keep thinking that in about 10-14 days things are going to really explode? I was convinced that we were going to have an early July Cape Verde storm. Now here were are one day from Aug 1st and the feeling is that we're a week to 10 days away from the tropics exploding.


We said that in Mid-June and what do you know.. we had Alex. This time, the ingredients are there and its getting deeper into the season.
Member Since: Posts: Comments:
Member Since: Posts: Comments:
Quoting IKE:


thanks....


I should probably note that I don't know if there's a way to make it go out to the EATL. This is the only one I know of, though.
Member Since: March 7, 2007 Posts: 597 Comments: 21099
Just a wait and see now, looks like a giant soup out there in the EATL. They deactivated 90L and at 8 am still had 20%. Tells me they still think something out of this area has a chance of developing and it absorbed 90L.

Member Since: Posts: Comments:
Quoting CybrTeddy:


No, they're watching it in case it pulls together further on in the Caribbean.
SHOWER AND THUNDERSTORM ACTIVITY ASSOCIATED WITH A TROPICAL WAVE
OVER THE CENTRAL CARIBBEAN SEA HAS DIMINISHED. ANY DEVELOPMENT OF
THIS SYSTEM SHOULD BE SLOW TO OCCUR...BUT THERE IS STILL A LOW
CHANCE...20 PERCENT...THAT IT WILL BECOME A TROPICAL CYCLONE DURING
THE NEXT 48 HOURS AS IT MOVES WESTWARD AT ABOUT 15 MPH INTO THE
SOUTHWESTERN CARIBBEAN SEA.

Member Since: October 9, 2008 Posts: 0 Comments: 8424
yep you are righht CybrTeddy I kinda lost hope on the area that was once known as 90L R.I.P. 90L
Member Since: Posts: Comments:
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
Member Since: August 12, 2009 Posts: 0 Comments: 203
1132. IKE
Quoting IKE:


Do you have the UKMET? I can get it out to about 48-60 hours and that's it.


No, UKMET went ECMWF and are restricting free access to their model. If you want to see it, $$.
Member Since: Posts: Comments:
I'm sure we'll see people on here before too long coming out and saying 'yep, season's a bust, Dr. Gray's wrong as usual', ect.
Member Since: Posts: Comments:
I bet they are too Ike.I hate it that they decided to scaleback on their clean up crews.All of that oil has got to come up somewhere on the coast.I just hope we dont get a major system and it upwells the water and pushes it all in.
Member Since: Posts: Comments:
Quoting IKE:


Do you have the UKMET? I can get it out to about 48-60 hours and that's it.


This site has one that goes out to 72 hours, should you be interested (left side of the screen).
Member Since: March 7, 2007 Posts: 597 Comments: 21099
1127. KRL
Quoting SLU:
Shows you how these US hurricane models are crap.


Exactly! Models are just that MODELS, nothing more, nothing less. Far too many people give them long range credence which usually doesn't materialize into any reliable accuracy.

When you're observing them about 24 to 48 hours out, then you start to see their true cone of value and significance.
Member Since: Posts: Comments:
1125. IKE
Quoting nrtiwlnvragn:


You got links to another country's hurricane models?


Do you have the UKMET? I can get it out to about 48-60 hours and that's it.
Member Since: Posts: Comments:
Quoting Hurricanes12:


They had increased it last night at the 2A.M. I'm pretty sure. However , they kept the odds to 20% today. They are maybe anticipating a miracle? LOL.


No, they're watching it in case it pulls together further on in the Caribbean.
Member Since: Posts: Comments:
they have done it before IKE
Member Since: Posts: Comments:
Quoting SLU:
Shows you how these US hurricane models are crap.


You got links to another country's hurricane models?
Member Since: Posts: Comments:
1121. IKE
Quoting reedzone:


Not saying you're a downcaster, but you do tend to post more when storms are dying.. Though this has been de-actvated, and it deserved to be because the circulation ripped apart do to the interaction of the one wave leaving and the other joining in. 91 should be coming soon with this mess and I still think we have potential for some development down the road.. yeah I know.. call me a wishcaster :P I just don't see how nothing can evolve out of this when it gets to "the area".


Life is easier without tropical development. I'm sure BP is thankful, if they can finish the relief well.

Quoting SLU:
Shows you how these US hurricane models are crap.


Member Since: Posts: Comments:
1101. aspectre 12:04 PM GMT on Julio 31, 2010


What parameters create the difference between the SeaIceExtent and the SeaIceArea charts?

Good info here On Arctic Sea Ice charts:

http://neven1.typepad.com/blog/
Member Since: Posts: Comments:
Quoting CybrTeddy:
Huh, I didn't notice they upped the odds on the Caribbean AOI to 20%. No convection whatsoever with it.


They had increased it last night at the 2A.M. I'm pretty sure. However , they kept the odds to 20% today. They are maybe anticipating a miracle? LOL.
Member Since: Posts: Comments:
Quoting wunderkidcayman:
well IKE you know that they can reactivate if 90L make a good comeback


90L as I said yesterday probably won't develop, rather that huge African wave might. Its a wait and see right now, but I do foresee development before too long.
Member Since: Posts: Comments:
Quoting wunderkidcayman:
well IKE you know that they can reactivate if 90L make a good comeback


90L has become absorbed. It's not going to make a comeback. I'm not sure why it matters, anyway. The wave behind it could eventually enter the Caribbean.
Member Since: March 7, 2007 Posts: 597 Comments: 21099
Huh, I didn't notice they upped the odds on the Caribbean AOI to 20%. No convection whatsoever with it.
Member Since: Posts: Comments:
well IKE you know that they can reactivate if 90L make a good comeback
Member Since: Posts: Comments:
1114. SLU
Shows you how these US hurricane models are crap.
Member Since: Posts: Comments:
Quoting mrsalagranny:
Could it be that the models were picking up on the wave that is going to absorb 90l?And that is where they were making their predictions.


Yep. This area still has a good chance of development, NHC hasn't dropped the odds.
Member Since: Posts: Comments:
Could it be that the models were picking up on the wave that is going to absorb 90l?And that is where they were making their predictions.
Member Since: Posts: Comments:
1111. IKE
Quoting mrsalagranny:
Thanks Ike.Does that mean that there may be tropical trouble on the 8-14 day time period?I was wondering because it said above normal precips.TIA.Im new at this so plz bare with me and all my silly questions.


There might be a chance.
Member Since: Posts: Comments:
Quoting IKE:


SHIPS...wrong.
LGEM....wrong.
GFDL....wrong.
HWRF....wrong.

Two days ago quite a few on here were really excited about 90L. Too excited. Live and learn....

Once Bitten, Twice Shy?


Not saying you're a downcaster, but you do tend to post more when storms are dying.. Though this has been de-actvated, and it deserved to be because the circulation ripped apart do to the interaction of the one wave leaving and the other joining in. 91 should be coming soon with this mess and I still think we have potential for some development down the road.. yeah I know.. call me a wishcaster :P I just don't see how nothing can evolve out of this when it gets to "the area".
Member Since: Posts: Comments:
Should see 91L shortly on that African wave.
Member Since: Posts: Comments:
Quoting IKE:


SHIPS...wrong.
LGEM....wrong.
GFDL....wrong.
HWRF....wrong.

Two days ago quite a few on here were really excited about 90L. Too excited. Live and learn....

Once Bitten, Twice Shy?
Well, it's back to the way you like it... enjoy it, cause it won't last very long! lol :P
Member Since: August 12, 2009 Posts: 0 Comments: 203
Quoting IKE:


About the 2nd week in August it may change according to....

8-14 DAY OUTLOOK FOR AUG 07 - 13 2010

THE ENSEMBLE MEAN SOLUTIONS FOR THE 8-14 DAY PERIOD ARE SIMILAR TO THE PATTERN
PREDICTED FOR THE 6-10 DAY MEAN OVER THE CONUS. THE CORRESPONDING 8-14 DAY
TEMPERATURE AND PRECIPITATION OUTLOOK IS THEREFORE SIMILAR TO THE 6-10 DAY
FORECAST. THE ANOMALY CENTER ASSOCIATED WITH THE MID-CONTINENTAL 500-HPA RIDGE
IS PREDICTED TO BE A BIT MORE TO THE NORTH OF THE PREDICTED POSITION ON THE
6-10 DAY FORECAST. THUS, THE BEST CHANCES OF ABOVE NORMAL TEMPERATURES IN THE
8-14 DAY PERIOD ARE NEAR THE LOWER GREAT LAKES. THE NAEFS PRECIPITATION
FORECAST INDICATES ELEVATED CHANCES OF ABOVE MEDIAN PRECIPITATION ALONG PARTS
OF THE CENTRAL GULF COAST.STRONG> A TROUGH DEVELOPS OVER SOUTHWEST ALASKA BETWEEN THE
6-10 AND 8-14 DAY PERIOD, INCREASING THE CHANCES FOR BELOW NORMAL TEMPERATURES
AND ABOVE NORMAL PRECIPITATION IN THE SOUTHWEST AND ALONG THE SOUTH COAST OF
ALASKA.


But even then at 8-14 days the temps....

Thanks Ike.Does that mean that there may be tropical trouble on the 8-14 day time period?I was wondering because it said above normal precips.TIA.Im new at this so plz bare with me and all my silly questions.
Member Since: Posts: Comments:
1106. IKE
Quoting Tropicsweatherpr:
90L is gone.

NHC_ATCF
invest_DEACTIVATE_al902010.ren
FSTDA
R
U
040
010
0000
201007311150
NONE
NOTIFY=ATRP
END




SHIPS...wrong.
LGEM....wrong.
GFDL....wrong.
HWRF....wrong.

Two days ago quite a few on here were really excited about 90L. Too excited. Live and learn....

Once Bitten, Twice Shy?
Member Since: Posts: Comments:
Tropical Update July 31st. 2010
Member Since: Posts: Comments:
1102. DESteve
I think we all need to relax and go to the trusted source did anyone check the Farmers Almanac ?? LOL

Good Morning all.. Hoping everybody has a great weekend.. will be watching these waves more to come ..

(From Project PREDICT : http://www.eol.ucar.edu/projects/predict/ )

http://met.nps.edu/~mtmontgo/storms2010.html

Member Since: Posts: Comments:
What parameters create the difference between the SeaIceExtent and the SeaIceArea charts?



Even after taking into account the shortening of the time period shown, the NSIDC site appears to smooth its lines in comparison to the JAXA site. Is that true? and why?
Member Since: Posts: Comments:
1100. IKE
Quoting mrsalagranny:
You are right Ike.How long before it is through?I dont think Mother Nature has much more patience left.


About the 2nd week in August it may change according to....

8-14 DAY OUTLOOK FOR AUG 07 - 13 2010

THE ENSEMBLE MEAN SOLUTIONS FOR THE 8-14 DAY PERIOD ARE SIMILAR TO THE PATTERN
PREDICTED FOR THE 6-10 DAY MEAN OVER THE CONUS. THE CORRESPONDING 8-14 DAY
TEMPERATURE AND PRECIPITATION OUTLOOK IS THEREFORE SIMILAR TO THE 6-10 DAY
FORECAST. THE ANOMALY CENTER ASSOCIATED WITH THE MID-CONTINENTAL 500-HPA RIDGE
IS PREDICTED TO BE A BIT MORE TO THE NORTH OF THE PREDICTED POSITION ON THE
6-10 DAY FORECAST. THUS, THE BEST CHANCES OF ABOVE NORMAL TEMPERATURES IN THE
8-14 DAY PERIOD ARE NEAR THE LOWER GREAT LAKES. THE NAEFS PRECIPITATION
FORECAST INDICATES ELEVATED CHANCES OF ABOVE MEDIAN PRECIPITATION ALONG PARTS
OF THE CENTRAL GULF COAST.
A TROUGH DEVELOPS OVER SOUTHWEST ALASKA BETWEEN THE
6-10 AND 8-14 DAY PERIOD, INCREASING THE CHANCES FOR BELOW NORMAL TEMPERATURES
AND ABOVE NORMAL PRECIPITATION IN THE SOUTHWEST AND ALONG THE SOUTH COAST OF
ALASKA.


But even then at 8-14 days the temps....

Member Since: Posts: Comments:
90L is gone.

NHC_ATCF
invest_DEACTIVATE_al902010.ren
FSTDA
R
U
040
010
0000
201007311150
NONE
NOTIFY=ATRP
END

Link
Member Since: Posts: Comments:
1098. IKE
Watching Tropical Waves in the Atlantic

Jul 31, 2010 7:52 AM

There are a couple of tropical waves worth monitoring across the Atlantic Basin. None show any signs of immediate development. One wave is moving across the Caribbean. As of late on Saturday morning, it was centered near 15 north and 65 west. It has sparse convection this morning. But wind shear is very light across the western Caribbean. This system will probably not form until it reaches the western Caribbean early next week where it will have a good opportunity to develop. Its expected track will likely take it into Central America before it has a chance to affect the United States. There are a couple of tropical waves moving across the eastern Atlantic. The most organized wave appears to be near the Cape Verde Islands. Computer models had been robust in strengthening this system in recent days, but the latest models have backed off. Still, the water is warm and atmospheric conditions are marginal for development. On its current track it will reach the Lesser Antilles by Wednesday or Thursday of next week.

By AccuWeather.com Expert Senior Meteorologist Dave Samuhel
Member Since: Posts: Comments:
You are right Ike.How long before it is through?I dont think Mother Nature has much more patience left.
Member Since: Posts: Comments:
Quoting palmasdelrio:

Where are you? It's 8 AM in Puerto Rico and it already feels like 90 degrees.

Really? It feels more like 85 degrees here, but it's just because I'm in the mountainous part of Vega Alta.
Member Since: Posts: Comments:
1095. IKE
Quoting msgambler:
I'm great granny, how about yourself? 90L can take her friend and go play anywhere but here.


With a high pressure heat dome....don't take my word at this, but nothings coming around here tropically for at least 7-10 days. Great for getting the relief well finished in the GOM!
Member Since: Posts: Comments:
1093. IKE
Quoting InTheCone:
000
ABNT20 KNHC 311144
TWOAT
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
800 AM EDT SAT JUL 31 2010

Beat me to it -

quiet in here this morning, all the wishcasters are worn out!


They'll be back. Give em a couple of hours.

GFDL had 90L at 63 knots this afternoon....




HWRF had 90L at 52 knots tomorrow....




...........................................


I don't get it with these models. What is the reason for them being wrong?
Member Since: Posts: Comments:
Quoting eyesontheweather:
Isn't all the convection south of the equator and doesn't that have an effect of it staying south. Just wondering?

Convection is North of the Equator. It's probably the 5N line that you think is the Equator.
Member Since: Posts: Comments:
Most definately.I hope and pray she stays(or him)as far away from the GOM as possible.I finally figured out how to upload my photo.LOL!!!!!!!
Member Since: Posts: Comments:

Viewing: 1141 - 1091

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35Blog Index

Top of Page

About

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

Local Weather

Overcast
58 °F
Overcast