Tranquility

Tranquility
Sunset in a Senegalese Village

Wednesday, July 30, 2014

Storm that downed Air Algerie 5017 may become a tropical storm Bertha this week


Flight path and wreckage site (source: BBC)

The path of 5017 was clearly into the mesoscale convective system.  The latest is that the pilots asked to return back to Ouaga as they probably realized that they could not fly through this storm (http://www.bbc.com/news/world-africa-28528174).  It is unclear whether they were in trouble at that point or not.

I have completed additional analysis of this storm.  Based on the analysis the storm was growing in size with the top of the clouds between -50 and -73C which going to be somewhere between 12 and 16 km (39,000-52,500 ft). For planes that fly at altitudes of 39,000 feet, typical temperatures are about -50 to -55C which means that flight 5017 would not have been able to climb above many of the storms.  


Cloud top temperatures at 0000 UTC or 1 hour 17 minutes before 5017 takeoff

As you can see in this picture at midnight (local time), there is a large area of clouds between 200 and 220 Kelvin (-73 to -53C), an hour prior to the flight taking off.  The plane should have been diverted to the west of the storm or potentially east, but the forecasters may have seen thunderstorms to the east near the Mali, Niger border and opted not to send them that direction.  Of course sending them directly into the storm makes absolutely not sense.

Cloud top temperatures at 0100 UTC 17 minutes before 5017 takeoff.

At 0100 (local time) we see that there has not been much movement in the storms position prior to takeoff, which should have definitely prompted a delay or a diversion to the west of the storm.  Given the large area of cold cloud temperatures, this was a large area of thunderstorms, which without a weather radar in the northern part of the country, could not have been easily maneuvered through  by Air Traffic Control.  While the aircraft does a radar in the nose of the plane, it only sees nearby thunderstorms.  

Cloud top temperatures at 0200, 10 minutes after contact with flight 5017 is lost

By 0200 UTC, the area of cold clouds have moved east and expanded.  This is 10 minutes after radar contact was lost.  Given where the crash site occurred, it is possible that the plane made it through much of the system, but that potentially there was some damage or maybe a buildup of super-cooled water on the pitot tubes.  The exact cause will be known by black boxes.  RIP 5017 passengers and crew.

However, the story does not end there.  Normally, such mesoscale convective systems (MCS) are long-lived and may continue for another thousand miles.  In this case, that is the story of this particular MCS.  Throughout the day, the system continue to grow and evolve.  It appeared to decay near Guinea, but really did not and the convection was regenerated as it left the coast.   

 Satellite picture of the convection linked to flight 5017 for July 24-July 27 (3 hours intervals)


The speed of the MCS suggests that it was not moving with an African Easterly wave but faster. It is possible that a mid-level circulation was generated in the organized convection.  Finally, the Guinea highlands have been known as a region where spin can be generated when organized convection is cross it over and moving over the Eastern Atlantic Ocean.


Once the convection made it to the central Atlantic, it appears it linked up with the inter-tropical convergence zone or a monsoon trough and the convection was reinvigorated.     It is possible that the convection itself may have generated spin--- in what is known as a bottom-up formation of tropical cyclones over the ocean.  The following movie shows how the convection evolved in Atlantic on July 27 and 28th.

Satellite picture of the convection linked to flight 5017 for July 24-July 27 (3 hours intervals)


This morning the system is not looking strong but there is a 70% chance of tropical cyclone formation over the next few days.

Visible Image Tropical disturbance July 30, 1445 UTC (1045 EST) 

The deep thunderstorms (convection) are scarce this morning and the low level center is exposed.  However, the overall environmental conditions are favorable for further development.   Assuming that this system survives, the current model tracks are taking the system into the Northern Caribbean by this weekend. It is too early to determine if this system will impact the US as it needs to form first.


Potential track of the current Tropical Disturbance (Invest 93) based on weather models


In summary, this was a unique tropical disturbance whose origins go back to the West Africa and is notable because of the tragic situation associated with mesoscale convective system over Burkina Faso.  The future of the system remains unclear but the genesis of tropical depression is possible over the next  day with additional development into Tropical Storm Bertha is possible later in the week.

Even though we are anticipating a lower than normal number of Atlantic tropical cyclones, it is virtually impossible to know which tropical disturbance may ultimately develop into a tropical cyclone.  Make sure that you remain aware and have your emergency preparation plan in place if you live in coastal areas.


Friday, July 25, 2014

Based on wreckage location - Air Algerie impacted by a mesoscale convective system



Crash Site of Air Algerie 5017 near the Burkina Faso/Mali Border 


Based on where the flight crashed today (Northern Burkina Faso/Southern Mali), it seems that the mesoscale convective system which had been in northern Burkina Faso may have played a major role in the accident.  The path of the aircraft seems 

Satellite Precipitation rate image at 0145 UTC Thursday morning (July 24)
to have been across the mesoscale convective system which was moving to the west.  The only way to avoid it would have bee to fly to the west or to the east around the storm, which would increase the travel time but would have been much safer.

This particular storm definitely had lightning with it, and as I stated in the earlier blog that it probably had significant amounts of ice and strong vertical updrafts.  Another danger is super-cooled liquid water.  Water normally freezes at 32F but it is possible for water in thunderstorms to remain as liquid well below 32F to nearly -40F.   The problem is that if this water should land on a piece of metal it will immediately freeze and cause ice to build up.   This is one important reason why to avoid deep thunderstorms.

A very important instrument on all planes is the pitot tube, which you often see if you look closely at aircraft.
Pitot Tube



 It provides important information about airspeed and how fast the plane is going.  If this instrument were get supercooled water on it and ice were to build up, it would very likely give a false sense of how fast the plane is going.  This is what happened in the case of several years ago (2009) when an Air France Jet flew into thunderstorms when traveling from Brazil to France.  The pilots did not know how fast the plane was going, and the plane (Airbus 330)  stalled and then fell some 35,000-39,000 feet to the ocean surface.  This has happened on a number of aircraft encountering thunderstorms.
http://www.aviationtoday.com/regions/usa/More-Pitot-Tube-Incidents-Revealed_72414.html#.U9LKRYBdUjA




Pitot Tube on a commercial jet

Organized West African Mesoscale Convective systems, grow very deep (up to 50,000 ft) and so they may impossible to fly over in a commercial jet.  Because they have lots of lightning, ice, strong updrafts and potentially supercooled water they should be avoided at all cost.  I am not sure why this plane was given a flight path which took it right into the heart of one of these systems as I am sure that forecasters were aware of it.  Clearly the pilots tried to deviate but maybe did not understand the largeness of this system and did not deviate far enough.    The Black box will probably yield useful information about what went wrong, but I feel very sad that the passengers had to encounter such a weather system.

It is quite a paradox, given that the rain has been below normal in many areas of West Africa and the types of systems that probably downed this plane are the ones that give life saving rains to the farmers in West Africa.  Except there have not been many of them this year -- thus far, with cities such as Dakar not having received any rain as of yet.

Again, the technology to avoid such weather hazards currently exist but is not deployed in a meaningful way in West Africa.  


Addition at 905 PM
There was discussion about a dust storm in the region.  However, dust will be located much closer to the ground and would definitely be located at less than 15,000 feet.  It seems improbable that dust was the cause of the crash unless the pilots were flying very low and dust somehow caused their engines to stall.  The black box will provide the best evidence based on their altitude.






Thursday, July 24, 2014

Did Weather play a role in the crash of Flight 5017 Today??



Flight Path of 5017 from Ouga to Algiers (Source: Chicago Tribune)

Last night around 9:50 PM Eastern Standard Time, Flight 5017 which departed from the capital of Burkina Faso, Ouagadougou (or sometimes called Ouga) some 50 minutes earlier lost contact with
Air Traffic Control Radar as it travelled to Algeria.    Tonight the wreckage was found in Mali but the exact location seems to be somewhat confusing.  Daylight will come up again in 4-5 hours and an exact determination will be known.  One thing that is known is that the pilot as to divert from some bad weather that was occurring along the flight path.

Satellite images indeed show heavy weather in Northern Burkina Faso and Southern Mali which would have caused the plane to deviate.  However, the area of bad weather, based on cloud top temperatures and rain rates was not very large and should have easily been avoided based on the forecast from the Capital.

1 AM satellite image of Convective System to the Northeast of Ouga.

Precipitation estimates show the heaviest rainfall falling near the cloud cluster for the next hours time.
EUMETSAT Rain rate estimates at 115 UTC




At 1:30 AM and145 AM  the area of heavy rain is still found over Northern Burkina Faso and Southern Mali.  A second area of lighter convection is found over the area where the plane went down at this time.



EUMETSAT 130 and 145 AM identified areas of heavy Precipitation.


By 200 AM, the only significant area of precipitation should have been south of the plane wreckage site but with areas of lighter precipitation near the wreckage site.


0200 UTC (2AM) EUMETSAT precipitation patterns.

I would have to assume that if there had been contact at 150 AM, that the pilot should have diverted around the area and maybe passed the area of heavy thunderstorms.  This is certainly true if the wreckage is found closer to the Algerian border.  I have looked at winds and vertical shear over the area and the winds were not that strong (not out of the ordinary) and the vertical wind shear was very light at the time.   

Even though the thunderstorms (convection) over Eastern Mali looks relatively weak, it does appear to be associated with lightning based on the WWLLN (University of Washington) ground based systems.  Lightning occurs in most of the organized convective systems, because we believe that desert dust serves as a good source of ice nuclei which makes the top of the thunderstorms ice filled, separated from liquid or mixed (liquid/ice) parts of the thunderstorm below.  This creates charge separation which brings about lightning.  

WWLLN lightning  activity between 0100-0200 UTC

WWLLN lightning between 0200-0300 UTC


Based on the WWLLN data, there was lightning along the original path and also in eastern Mali.  So it is possible that while the areas of rain appear light, they may have been stronger than expected because lightning is an indicator of 
convective activity and updrafts (which pilots always want to avoid).   The other possibility is that the plane was struck by lightning, leading to some type of systems failure or a possible breach (such as a door) leading to decompression of the plane.  


The area of strong thunderstorms in Burkina Faso were large and strong and so hopefully the pilot avoided this area.  I would have to assume that flying though this initial areas would have posed a significant threat to the aircraft, with lightning, severe turbulence and possible mechanical failure.  However,  in the event that it was avoided, the area of weaker thunderstorms in Eastern Mali may have been the cause of the downed aircraft through lightning or a some rogue updrafts.  

Addressing Weather Hazards in West Africa 

The lack of weather observations, including radars, put many people in harms way each wet season.  The numbers of weather related fatalities in West Africa remain unknown at present.   There is currently the satellite system along with software that could greatly empower forecasters to protect the general population and commercial transportation.  While the number of weather related fatalities cannot be brought to zero it can be greatly reduced.  Why this has not happened is unclear to me but the environment can be monitored and weather hazards can predicted. 


The types of weather systems (mesoscale convective systems) are long-lived and difficult to predict with our currently models but once they form their lifetime can be easily monitored.  For example the system over Burkina Faso at 0200 this morning was transformed to a much larger system by this evening impacting many more people.  As of 10 PM, the system is coming to an end in its lifecycle over Guinea. 

Thursday 645 PM Mature Mesoscale Convective System evolved from the 1 AM system


While Satellites will help us in monitoring West African convective systems, we must improve our understanding through measurements and increase the observation system in each country.  This will provide the nowcasting capacity which will give forecasters the proper tools to monitor  fast moving systems.  Lightning data at 15 minute intervals which the UK Met service has said it will provide to all Meteorological Services should be utilized for the protection of life and property.

Eventually, the recovery of the black box will provide the answers to what happened today.  While it cannot bring the loved ones back to their families it may provide guidance on if weather played a big role in the crash and if so how future weather related accidents can be avoided.  May the 116 souls of flight 5017 rest in peace.
















Sunday, July 6, 2014

Goree Island -- A resort/tourist Island or a memorial/historical site for the African Diaspora

Goree Island


Each year so many people go to visit Goree Island which is less than 5 miles from Dakar and when you walk into the port at Dakar there is always a sense of excitement.   People have the look of a vacation, a resort or just a day of nice lunch and a swim on the beach.
The Port of Dakar for boarding (Badji and other HU students in the picture) 


But I wonder why I never feel have that feeling nor have I ever felt like that in the many times that I have been  there since 1993.  There is a cost to go to take the ferry to Goree --- 10 dollars round-trip if you are a foreigner and 1 dollar tax to help maintain Goree.  I ain't mad at that because they need income.  The real question is what is so special about Goree and why is more than a storefront.  


When you go to Goree, there are people asking if you want to go to the slave house.   But it is not visible from the shore and hidden back in the cut.  When you arrive you see kids swimming and restaurants and people chilling on the beach.  Merchants buzzing around asking you for a tour of the island and to buy beads, bracelets and clothing.  It does appear to be a resort.  

The beach at Goree



It is only after walking round a bit on the island that you find a inconspicuous place called the Slave house.




President Obama at the House of the enslaved




This one remaining slave house on Goree was preserved by the late Joseph Ndiaye who kept the voices of the ancestors alive by not allowing the history of Goree to be washed away in the history books or by tourism.   Mr. Ndiaye was a force to be respected because of his commitment to the truth and legacy of the enslaved that happened on Goree.   I first had the honor of meeting Mr. Ndiaye in 1993 on my first visit to Senegal.  Up until his untimely death, I always went to Goree and in particular to see the master, Mr. Ndiaye at work.    I continue to visit Goree each year.   


The late Joseph Ndiaye

During the great gathering in 1995 -- the Million Man March in Washington DC, Mr. Joseph Ndiaye was one of the speaker.  That was really special to hear him and I am sure that it was equally special to see the sons of the enslaved ancestors stand before him and listen.


Mr. Joseph Ndiaye's Million March Picture




Upon entrance, you always see a beautiful set of stairs but it is a mysterious door that grabs your attention which opens to the sea.  You have a momentary thought about it,....something fearful about that door.
The Door of No Return 


But you are directed to your left to other rooms in a very short time your heart begins to sink into a place that is dark and fearful where the reality begins to creep in on you as you walk in.   Rooms for children, men, woman, infants and those considered rebels.













Cell for the Recalcitrants 

As you move towards the end of the tour, the place becomes very dark and lonely.  It as if you can feel that each ancestor was afraid and alone.  They approached that final place which would take them to another world or beyond this life if they did not survive the middle passage.







Everything is leading you to slaveships where are docked off of Goree waiting to move human Cargo.  Just one more door.... Been here suffering for the last 90 days and no one to come and save me.




The door of no return


The ancestors think: It is here where our memories will be lost, our hope has finally faded.  Will we be remembered???



Yes, you will be remembered and loved again because Joseph Ndiaye did not let us forget you.



We will not forget you because we will come back.  Yes there will be feelings of sadness, tears and anger but we are grateful because through your sacrifice we are here.  Your life was not in vain.

Those who returned to the door of no return.


Which brings me back to my original statement about should entire island of Goree be a memorial or historical site to the African diaspora -- whether you are from Brazil, Haiti, South Carolina, California, the Bahamas or Barbados?   I was watching CNN the other morning and they were talking about the economic disparities in Brazil at the World Cup 2014.  A foreigner who lived in this neighborhood for 35 years was asked why it was so bad there.  His answer:  The are children of slaves (enslaved).   He is right and the same types of disparities can be seen at many places in the African diaspora. 


Map of where the enslaved were taken to.


When you go south into Gambia, and visit James Island -- Where Kunta Kinte (ROOTS) was captured the island is a uninhabited and the rising sea is going to take it away.  It seems fitting for a place where humans were captured, held and traded for hundreds of years.  
James Island in Gambia



 Slavery on Goree may have begun as early as 1444 by the Portuguese and continued until 1815 (French).  Even if we are being conservative, the slave business was on the island for probably 300 years.  I am told that there were 28 slave houses, which held between 150-300 persons for up to 90 days before they were shipped out.  This is easily several million persons to have been held on this Island over the 300 year period.    It is unclear how many died from sickness and were thrown to the sharks that were known to swim around the island.   So when I am putting my feet in the water at Goree, I frequently think  that Goree  is not like other beaches.  These waters carry something sacred.

I watch the kids have fun and when the boat takes us back to Dakar, the boys are always asking people to throw coins to them in the water.  This practice makes me very angry  and is not respectful because of what happened on this island.  
Boys near the ferry asking for coins to be thrown in the water.
  While it seems like a lot of fun, and the kids are diving off the boat, that nagging feeling about Goree remains.  

Boy Jumping off the Ferry at Goree 


 I know that no matter how many times I go to Goree, there will always be a feeling of sadness and yet hope because I am alive due to someone who survived the middle passage.   Goree is a living memorial because of Joseph Ndiaye.   I am sure that I will ever be able to think of it as a resort.....I am certain of it.



Thanks Mr. Joseph Ndiaye.  Maybe we should begin the dialogue of rebuilding and restoring Goree for what it represents and its connections the rest of the African Diaspora. 









Tuesday, July 1, 2014

Tropical Storm Arthur forms and projected to move up the east coast (July 4-6)


Visible Image of Tropical Storm Arthur 1:15 EST


The first Atlantic Tropical Cyclone - Arthur,  formed today and is expected move up the east coast this week.  While it is currently at Tropical Storm with 40 MPH winds, the outflow is good and it is expected to become a hurricane in the next 48 hours or so.  The models are currently carrying it up the east coast with the primary impacts coming near the Outer Banks.  But don't get caught up on the path of the storm.  It may well create rough ocean conditions and rip currents even on Friday, when it may be very far from the coast impacting VA, MD, DEL and possibly NJ beaches depending on the intensity and size of the storm.  If you are going to the beaches, please keep this in mind, especially if you have children and if you know young adults who may not heed the warnings.  Three young people got caught up in rip currents last year when I was as the beach and one of them died.


Projected Path for Tropical Storm Arthur


This is a reminder, that although the current hurricane forecast is for below normal tropical cyclones in part because of El Nino conditions (warmer temperatures) in the Eastern/Central Pacific Ocean which is expected to produce more westerly shear.

Ocean Temperatures (top) and temperature anomalies bottom with yellow showing warming temps.



This means that the winds at 15,000-40,000 ft are expected to be disruptive to tropical cyclones making them less likely to form or to become major hurricanes.   The problem is that this is primarily true to for tropical latitudes (10-25 degrees latitude) and for disturbances from West Africa.  Not all tropical cyclones will come from African disturbances (such as TS Arthur) and further, hurricanes are discrete events which means that there will be times when they form and the wind shear is low.   Finally our understanding of the science around the genesis of tropical cyclones and their life-cycles is incomplete.

With the advent of Hurricane Season on June 1, make sure that you are ready if you live in coastal regions and even if you don't during the summer severe thunderstorms often occur and have the potential to knock out the power.

With the development of TS Arthur -- The hurricane season has begun.