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96L Off the Coast of Africa Growing More Organized

By: Jeff Masters 2:01 PM GMT on July 28, 2016

A strong tropical wave that moved off the coast of Africa on Wednesday morning has become more organized over the far eastern Atlantic, and has the potential to develop into a tropical depression in the coming days as it tracks west-northwestward at 10 - 15 mph into the middle Atlantic. NHC designated this disturbance Invest 96L on Wednesday morning--the first "Invest" of the year for an African tropical wave. Satellite loops on Thursday morning showed 96L had a compact area of heavy thunderstorms, and this activity had acquired a modest degree of organization. Some spin was evident in the cloud pattern, and low-level spiral banding features had begun to appear. Wind shear was a light 5 - 10 knots, and sea surface temperatures (SSTs) were warm, near 28°C (82°F), which was about 1°C (1.8°F) above average. Water vapor satellite imagery showed that the eastern tropical Atlantic was quite moist, with the dry air of the Saharan Air Layer (SAL) several hundred miles north of 96L. These conditions are favorable for development of a tropical depression.


Figure 1. Analysis of the Saharan Air Layer (SAL) from 8 am EDT (12 UTC) Thursday, July 28, 2016, showed that the dry air and dust of the SAL lay a few hundred miles to the north of 96L. Image credit: University of Wisconsin CIMSS/NOAA Hurricane Research Division.

Forecast for 96L
Steering currents favor a west to west-northwesterly motion at 10 - 20 mph for 96L over the next five days, and the storm should reach a point near 40°W, midway between the Lesser Antilles Islands and Africa, on Sunday. The 8 am EDT Thursday run of the SHIPS model predicted modestly favorable conditions for development through Saturday morning, with wind shear in the light to moderate range, 5 - 15 knots, a moist atmosphere, and warm SSTs near 27.5 - 28°C (81 - 82°F.) However, on Saturday and Sunday, 96L will encounter cooler waters, with temperatures a marginal 26.5 - 27°C (80 - 81°F). The SHIPS model also predicts that wind shear over the weekend will become moderate to high, 15 - 25 knots, and the atmosphere will get very dry, due to an intrusion of the Saharan Air Layer (check out the 10-day African dust forecast from NASA.) These unfavorable conditions would stymie any development of 96L.

The Thursday morning operational runs of our three reliable models for predicting tropical cyclone genesis, the European, GFS and UKMET models, all supported some limited development of 96L, but stopped short of predicting it would become a tropical depression. The 00Z Thursday run of the GFS ensemble forecast, done by taking the operational high-resolution version of the model and running it at lower resolution with slight perturbations to the initial conditions in order to generate a range of possible outcomes, had more than 50% of its twenty ensemble members predict that a tropical depression would form this weekend or early next week in the eastern Atlantic. Most of these forecasts had the storm dying out the middle Atlantic, due to unfavorable conditions, and none had it becoming a hurricane. Between 10 - 20% of the 50 members of the 00Z Thursday European ensemble model forecasts showed 96L becoming a tropical depression. In their 8 am EDT Thursday Tropical Weather Outlook, NHC gave 96L 2-day and 5-day development odds of 30% and 40%, respectively. Though the long-range uncertainty on what 96L might do is high, one reasonable scenario is for the system to steadily grow in organization the next few days, come close to or achieve tropical depression status by Saturday, then get ripped up by wind shear and dry air well before reaching the Lesser Antilles Islands by the middle of next week. Should 96L become a tropical storm, the next name on the Atlantic list is Earl.

Eastern Pacific getting less active
For the first time since July 2, there is only one active tropical cyclone in the Eastern Pacific: Tropical Storm Frank, which peaked as a Category 1 storm on Tuesday. Frank is degenerating quickly over 23°C waters and is likely to dissipate by Thursday evening, potentially giving us on Friday our first tropical cyclone-free day in the Eastern Pacific since July 1. Beginning on July 2, the Eastern Pacific had Tropical Storm Agatha form, followed by Category 4 Hurricane Blas, Category 2 Hurricane Celia, Category 3 Hurricane Darby, Tropical Storm Estelle, Category 1 Hurricane Frank and Category 4 Hurricane Georgette. This puts us far ahead of climatology: the Eastern Pacific usually does not see its seventh named storm until August 7, its fifth hurricane until August 26, and its third major hurricane until September 20. An average season has 15 named storms, 8 hurricanes, and 3 major hurricanes. The quiet may not last long: in their 8 am EDT Thursday Tropical Weather Outlook, NHC gave a new tropical disturbance a few hundred miles south of the southern tip of Mexico's Baja Peninsula 2-day and 5-day development odds of 20% and 70%, respectively. This storm--which would be named Howard if it gets to tropical storm strength--is expected to move west-northwest and not impact Mexico.

Jeff Masters

Hurricane

The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.

Reader Comments

97 better hurry up and become a cyclone . it will become scrambled if it doesnt. john hope rule
12Z Models on 97L have shifted South and West
Quoting 1000. wunderkidcayman:

I think new 12Z position for 97L is a bit off too far east and slightly to far North

Looking at satellite looks like further W and slightly S of where 12Z has it



97L file this updated

AL, 97, 2016072912, , BEST, 0, 138N, 410W, 25, 1011, DB

Quoting 1002. GeoffreyWPB:






Looking good
Morning all. At 1000 comments are we?
Quoting 1003. wunderkidcayman:

12Z Models on 97L have shifted South and West


12Z Models on 96L have shifted quite a bit South and West as well
Quoting 1006. win1gamegiantsplease:

Morning all. At 1000 comments are we?

Time for 2000 on the next blog
1009. IDTH
Good morning, should've known that what we were seeing from 96L was from the mid levels. Meanwhile 97L looks just dowright awful and the downward motion is definitely not helping right now but come tuesday, if this system is still alive and not racing away, the potential remains for this to develop.
Quoting 961. Climate175:

Individual Look
Invest 97L
Invest 96L

it looks like 96L is going more on a westerly course, even a little south of west. That could change the intensity forecast
1012. Drakoen
96L looks like it's on the verge of becoming a tropical depression. If this was in the GOM it would already be classified.
1013. IDTH



Okay downward motion associated MJO, suprresed Kelvin Wave, same thing in my books. It all = unfavorable for thunderstorm development.
Wow, 1000+ comments... By the way, who forgot the thermometer inside the fridge ?
if 96L takes a more W move then it will have vary low wind shear the hole way




96L could be come a biger issue come down the road then 97L right now


all so the saharan air is little too none for 96L




96L right now has every thing going for it
1019. hydrus
Quoting 1014. 999Ai2016:

Wow, 1000+ comments... By the way, who forgot the thermometer inside the fridge ?

It was Ron White...He was stirring his scotch with it.
Quoting 1016. Tazmanian:

if 96L takes a more W move then it will have vary low wind shear the hole way




96L could be come a biger issue come down the road then 97L right now


all so the saharan air is little too none for 96L




96L right now has every thing going for it



yeap
29/1145 UTC 12.6N 22.5W T1.5/1.5 96L -- Atlantic
Quoting 1016. Tazmanian:

if 96L takes a more W move then it will have vary low wind shear the hole way




96L could be come a biger issue come down the road then 97L right now


all so the saharan air is little too none for 96L




96L right now has every thing going for it


Agreed. If 96L takes a slower westward motion, it will overall be in a more favorable environment than if it took on a northwestward track. Shear is lower, less SAL and warmer SSTs if it took a westward path.
Could remain weak, miss the islands altogether and head into the GOM. Bears watching.

Quoting 1001. islander101010:

97 better hurry up and become a cyclone . it will become scrambled if it doesnt. john hope rule
1024. Ed22
Invest 97L looks to be slowing down thunderstorms increasing in momentum, this will continue throughout the day going into the evening with some decrease in forward speed. Tropical disturbance invest 96L on the verge of tropical depression five.
1025. LargoFl
Quoting 1024. Ed22:

Invest 97L looks to be slowing down thunderstorms increasing in momentum, this will continue throughout the day going into the evening with some decrease in forward speed. Tropical disturbance invest 96L on the verge of tropical depression five.


Yes, slow down slow down 97L xD
97L does not look very good, I don't expect it to develop until Sunday at the absolute earliest, if it even develops at all. 96L could become a TD tonight or tomorrow.
Quoting 1021. Tazmanian:

29/1145 UTC 12.6N 22.5W T1.5/1.5 96L -- Atlantic


Yay 96L at T1.5/1.5

All we need now is 97L at T1.0/1.0 or higher and we would be good

Quoting 1023. HaoleboySurfEC:

Could remain weak, miss the islands altogether and head into the GOM. Bears watching.




Or South of PR,Hispaniola and Cuba and with a upper level anticyclone giving it favoured upper conditions and passing over high SSTs and record high TCHP in the NW Caribbean we could see this bomb out in the NW Caribbean and GOM

Quoting 1024. Ed22:

Invest 97L looks to be slowing down thunderstorms increasing in momentum, this will continue throughout the day going into the evening with some decrease in forward speed. Tropical disturbance invest 96L on the verge of tropical depression five.


Both 96L and 97L needs to be watched closely
The last few frames are showing that 97L is now moving south of due west and there might be a relocation of the low centre to the southwest.
1030. Tcwx2

GFS going way south, probably too far south. I don't think this is the solution that we're looking for. I honestly believe that 97L is going to be a bigger threat than shown by the models currently, possibly becoming a threat to Yucatan, Mexico and/or Texas. Or maybe I'm getting ahead of myself. Time will tell we have plenty of time to watch. Buckle up, we are in for a roller coaster ride for the next three months.
The wave that became 2005's TD 10 took a somewhat similar track to what is currently forecasted for 97L. TD 10 struggled and it was anticipated to dissipate southeast of the Bahamas. It limped by and intensified in the Bahamas and was named Katrina.

Not saying 97L is the next Katrina or that it won't dissipate like so many other waves but HurricaneFan you are wise to keep your eye on it. Unless destroyed by the islands, it could find more favorable conditions in 48-72 hours.

Quoting 1027. HurricaneFan:

97L does not look very good, I don't expect it to develop until Sunday at the absolute earliest, if it even develops at all. 96L could become a TD tonight or tomorrow.
Quoting 1024. Ed22:

Invest 97L looks to be slowing down thunderstorms increasing in momentum, this will continue throughout the day going into the evening with some decrease in forward speed. Tropical disturbance invest 96L on the verge of tropical depression five.


Yes looking on new steering charts we should see a definite slow down in foward speed for 97L by the time it reaches 50W and more so after 60W
Quoting 1012. Drakoen:

96L looks like it's on the verge of becoming a tropical depression. If this was in the GOM it would already be classified.
lol...don't get the blog started on Colin..
Quoting 1029. stoormfury:

The last few frames are showing that 97L is now moving south of due west and there might be a relocation of the low centre to the southwest.


IT would make sense as the strongest vort associated with 97L is located further S
I wish we could have a better sat loop for 96L. Kinda hard to tell what's happening with a 3 hour gap between each frame.
Went back to the 2005 blogs and took a look at the TD 10/Katrina timeframe. Most of the blogs had less than a 1,000 comments. To my memory I swore there were many thousands of comments. Amazing how our memory becomes skewed by time. I was a lurker back then living in Maine. I only posted on the winter snowstorm blogs under a different handle (Snowhaoleboy, I think). Anyway, Katrina is always my go to example of how Mother Nature doesn't care about models.

I do remember the knot in my stomach watching K in the GOM.
1037. 882MB
Quoting 1035. Huracan94:

I wish we could have a better sat loop for 96L. Kinda hard to tell what's happening with a 3 hour gap between each frame.


Check out this loop. Uploads every 30 minutes. :)

Link
Eric Blake %u200F@EricBlake12 2h2 hours ago
Wow #AL96 looks a lot more organized overnight- starting off the Cape Verde #hurricane season a bit early this year?
Michael Ventrice %u200F@MJVentrice 5h5 hours ago
Still EARLY but there's growing evidence for 97L to track into the Gulf of Mexico... IF a system manages to spin up.
Oh I can't wait till hurricane hunters do the mission tomorrow for 97L

It will be interesting what they find
1040. Grothar
Too bad we don't have a "fast foward" button on our keyboards to move these systems.
Quoting 1019. hydrus:

It was Ron White...He was stirring his scotch with it.


The 34° is probably where he left his lit cigar butt.
Quoting 1016. Tazmanian:

if 96L takes a more W move then it will have vary low wind shear the hole way




96L could be come a biger issue come down the road then 97L right now


all so the saharan air is little too none for 96L




96L right now has every thing going for it


How is SAL little to none? there's dust all around 96L
Quoting 1016. Tazmanian:

if 96L takes a more W move then it will have vary low wind shear the hole way




96L could be come a biger issue come down the road then 97L right now


all so the saharan air is little too none for 96L




96L right now has every thing going for it

SAL seems to be our friend right now.
Quoting 1039. wunderkidcayman:

Oh I can't wait till hurricane hunters do the mission tomorrow for 97L

It will be interesting what they find


If they go in. Could be canceled
I currently have 97L on >>4X

Quoting 1040. Grothar:

Too bad we don't have a "fast foward" button on our keyboards to move these systems.
1047. LargoFl
97 sure has a long way to go before raising concerns,might just be a rain maker?........
Good morning all.
I gaze across the ocean
And what do I see?
2 tropical waves coming at me
My! Oh my what shall I do?
I will prepare myself
For whatever comes through

Have a great day everyone
1049. IDTH
97L will need to start slowing down if it wants to fire more thunderstorms. It is also moving into an area of warmer SST's but more drier air. 97L has a long road ahead of it. 96L meanwhile is probably in the best situation because it's still embedded in the ITCZ and does not have to worry about SAL nearly as much, also it is in an area of light shear and is much more organized and not moving nearly as fast. 97L could develop further west but it must survive first.
Quoting 1044. Hurricanes101:



If they go in. Could be canceled


They will go in
There is a slight chance they may not
I think they will we just have to see what 97L will do over next 24hr or so
1051. Houdude
Quoting 1035. Huracan94:

I wish we could have a better sat loop for 96L. Kinda hard to tell what's happening with a 3 hour gap between each frame.
Check out this loop. Uploads every 30 minutes. :)

Link


What's the URL for 97L on this sat server?
Quoting 1049. IDTH:

97L will need to start slowing down if it wants to fire more thunderstorms. It is also moving into an area of warme SST's but more drier air. 97L has a long road ahead of it. 96L meanwhile is probably in the best situation because it's still embedded in the ITCZ and does not have to worry about SAL nearly as much, also it is in an area of light shear and is much more organized and not moving nearly as fast. 97L could develop further west but it must survive first.

yep!
Quoting 1049. IDTH:

97L will need to start slowing down if it wants to fire more thunderstorms. It is also moving into an area of warme SST's but more drier air. 97L has a long road ahead of it. 96L meanwhile is probably in the best situation because it's still embedded in the ITCZ and does not have to worry about SAL nearly as much, also it is in an area of light shear and is much more organized and not moving nearly as fast. 97L could develop further west but it must survive first.


As I said multiple times it appears it's starting to slow and we should see a more definitive slowing down once it hits 50W and even more so once it hits 60W according to the recent steering flow charts
1054. 882MB
Quoting 1051. Houdude:

Quoting 1035. Huracan94:

I wish we could have a better sat loop for 96L. Kinda hard to tell what's happening with a 3 hour gap between each frame.
Check out this loop. Uploads every 30 minutes. :)

Link


What's the URL for 97L on this sat server?


Here you go.

Link
Quoting 1037. 882MB:



Check out this loop. Uploads every 30 minutes. :)

Link


DOH! I can't believe I forgot about that site. Thanks! :)
The wind shear is really the only factor for 97L once it hits the Caribbean and the shear is expected to move out as the upper anticyclone that currently protecting 97L moves in with 97L underneath the anticyclone
Decent ASCAT pass over 96L a moment ago. Definitely a LLC there, but winds aren't that strong enough to classify it yet.

Quoting 1012. Drakoen:

96L looks like it's on the verge of becoming a tropical depression. If this was in the GOM it would already be classified.
I couldn't agree more...again the tendency of the NHC to downplay the actual intensity and matter-of-fact development of tropical disturbances in the Atlantic Basin in particular is an issue which needs addressing in the soonest.
For us in the islands cases in point which had an unfortunately deadly impact with little lead-time of warning and preparation -thanks due solely -to delayed tropical system upgrading & mired meteorological bureaucracy of sorts are T.S Cindy Of 1993 (Martinique), & T.S. Debby of 1994 (St. Lucia). Both systems developed quote on quote 'near' the islands? A lot of data/ evidence begs to differ.
Additionally, extremely late, unreasonable & unjustifiably delayed system classifications occurred in the case of Emily (2011) (See link http://andrew.rsmas.miami.edu/bmcnoldy/tropics/emi ly11/Emily_01-02Aug11.gif ) & Pre-T.S. Helene (2012) as it made impact on the Central Lesser Antilles (as a Post Tropical depression?...), even Tomas (2010) can be applied somewhat to this scenario. And I personally think a very notable mess was made of keeping up with the true intensity of what was an obviously quickly strengthening Hurricane Danny last year (2015)... Let's hope this 'saga' can come to a long overdue conclusion for the sake of bonafide Tropical System Meteorology.

God Bless!
1059. IDTH
Quoting 1052. bigwes6844:


yep!


I just don't think it'll make it through the Caribbean.

I'm curious though, it still has the anticyclone around it which is definitely it's biggest positive but does an anticyclone work if it's moving into an area of highly unfavorable winds?
Quoting 1057. Bluestorm5:

Decent ASCAT pass over 96L a moment ago. Definitely a LLC there, but winds aren't so hot.


I hope they will catch 97L too
1061. LargoFl
Quoting 1059. IDTH:


I just don't think it'll make it through the Caribbean.

I'm curious though, it still has the anticyclone around it which is definitely it's biggest positive but does an anticyclone work if it's moving into an area of highly unfavorable winds?

if you look at those models that stay south of Cuba it has a chance but if it goes further south than that then this systems wont be able to form. Kinda reminds me of Chantal how fast its moving.
good spin on 96L. I wonder if NHC will go code red by 2pm est TWO.
1064. Tcwx2
I'll go ahead and say this: If 97L doesn't develop or become anything, I won't be too disappointing because honestly I think that all of us were surprised in the first place when the NHC drew the yellow crayon yesterday. It's only late July so we will definitely begin to see more and more tropical systems and eventually they will make it into the GOM, Caribbean and Bahamas without problem. I expect to see at least one major hurricane making landfall somewhere this season, it's been too long.
Quoting 1059. IDTH:


I just don't think it'll make it through the Caribbean.

I'm curious though, it still has the anticyclone around it which is definitely it's biggest positive but does an anticyclone work if it's moving into an area of highly unfavorable winds?


The way it's forecasted is that the anticyclone will move into the Caribbean and that stream of shear will curve around it and leave 97L protected from that shear under that anticyclone protection

Looking at it now compared to yesterday the E part of that high shear that over the E Caribbean/leeward Is. Western MDR is already shifting NE starting to curve around the anticyclone
I know everybody is watching 96L closely but Im really watching this one over Africa that has a better potential to be in better environmental conditions. It looks healthy and may become a depression quickly if it stays together long enough.
1067. IDTH
Quoting 1061. LargoFl:



Trending upward that's for sure. 97L is one of those that I just can't really get a good idea on.
Quoting 1062. bigwes6844:


if you look at those models that stay south of Cuba it has a chance but if it goes further south than that then this systems wont be able to form. Kinda reminds me of Chantal how fast its moving.


Actually if it goes further South it stands a better chance because of less interaction with land not to forget to mention the record high heat content in the NW Caribbean that will aid in intensification
Quoting 1060. wunderkidcayman:



I hope they will catch 97L too

Best we have. Still an open wave for most part, although the convection is picking up a bit. 97L is moving pretty dang fast at 20 mph and trade winds are only going to pick up from here on toward eastern Caribbean. I'm not expecting 97L to wrap around decently for the next couple of days.

JeffMasters has created a new entry.
1071. Patrap
97L

I'll go on and say this is the best looking tropical wave I've seen all season so far. This is definitely Earl before the weekend is up. IMO
Quoting 1064. Tcwx2:

I'll go ahead and say this: If 97L doesn't develop or become anything, I won't be too disappointing because honestly I think that all of us were surprised in the first place when the NHC drew the yellow crayon yesterday. It's only late July so we will definitely begin to see more and more tropical systems and eventually they will make it into the GOM, Caribbean and Bahamas without problem. I expect to see at least one major hurricane making landfall somewhere this season, it's been too long.


To be honest I was kinda expecting the yellow crayon I mean I saw other models hinting on this before NHC mentioned it and it would make sense for something to pop up there

Anyway I think we will see something out of 97L with not much problems and yes I think we will see plenty more and we are just getting started

Quoting 1067. IDTH:


Trending upward that's for sure. 97L is one of those that I just can't really get a good idea on.


Yep and I think as time goes forward we will see it getting higher and higher
Quoting 1040. Grothar:

Too bad we don't have a "fast foward" button on our keyboards to move these systems.


Actually with one of them 1000km directly upstream of me "delete" would be the key of choice.
WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
1000 AM EDT FRI 29 JULY 2016
SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD)
VALID 30/1100Z TO 31/1100Z JULY 2016
TCPOD NUMBER.....16-064

I. ATLANTIC REQUIREMENTS
1. NEGATIVE RECONNAISSANCE REQUIREMENTS.
2. OUTLOOK FOR SUCCEEDING DAY: POSSIBLE LOW LEVEL INVEST
AT 31/1800Z NEAR 16.0N 65.0W WITH 6-HRLY FIXES TO FOLLOW
AT 01/1200Z IF SYSTEM DEVELOPS.
1076. Xulonn
Quoting 1014. 999Ai2016:
Wow, 1000+ comments... By the way, who forgot the thermometer inside the fridge ?
Good argument for "adjusting" raw data sets that are used for historical data in determining long term temperature term trends.
1077. IDTH
.
I have frequented this blog many times since its inception and have been a member a few times. I also have lived along the Gulf Coast from birth-2010 and know how unpredictable the tropics are. What I do know is this regarding 96L and 97L: (1) they are only invests' and (2) if/when they obtain TD status, they will be watched closely. Just because there are warmer waters in locations this year than there were last year, does not mean much. Warm waters is just one ingredient needed for a storm to form. There are countless others. Even then, all have to come together at the right time and place.

I see far too many bloggers on here get all worked up over things that cannot be controlled. It is one thing to have a fascination about tropical weather and even make it a hobby. However, when it becomes annoying and down right foolish is when individual get so wrapped up in landfalls, paths and strength when we do not even have anything out there yet and they start making false predictions that do not even coincide with the data or with what the experts in the field are saying. That does not mean things change rapidly and the experts get it wrong, but to say things such as "the NHC better get the crayons out," or "the NHC waits until the last minute" are all things that should not be said. Are anyone of you at the NHC? Aren't we all human? Don't we all make mistakes at times?

Weather is all about probability. I am just happy that tropical systems are a weather phenomena that we have lead time to get away from. Ask the individuals in Moore, El Reno, Jerrell etc...and they would be happy to have a hurricane over a tornado. Besides the point, just wait until we get something out in the Atlantic before we all get too excited.

That is all I will say about this. And I don't want this to turn into an argument and I am not intending this post to start an argument. It is a mere observation. However, if one does start, I will delete this posting and not engage in those who want to argue.

Stay safe out there and if you are in a tropical weather zone, be prepared and monitor but go on about your daily lives.

Quoting 1064. Tcwx2:

I'll go ahead and say this: If 97L doesn't develop or become anything, I won't be too disappointing because honestly I think that all of us were surprised in the first place when the NHC drew the yellow crayon yesterday. It's only late July so we will definitely begin to see more and more tropical systems and eventually they will make it into the GOM, Caribbean and Bahamas without problem. I expect to see at least one major hurricane making landfall somewhere this season, it's been too long.


It is bound to happen. The odds are in favor this year for a landfall. Who knows if it will be Cat 3 or greater. We do need systems this year to release all of the energy that has been built up in the Atlantic the past 10 years.