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Skyguy

Scott747 wrote:Where does he say anything about the track of 99l other than it potentially tracking towards the Lesser Antilles?

Might want to mention to your fellow 'hobby mets' that the HWRF has only ran once for 99l and also only goes out to 126 hrs, which not only puts it no where near Florida, but doesn't even it put it in the Caribbean. ;)
I'm sorry, I meant to say GFS. But they and I are concerned about what happens after it reaches the Lesser Antilles, as that is a dangerous place for TC formation. SHIPS intensity model, interestingly enough, predicts at least a Cat 1 storm prior to any interaction with the islands.

P.S. I have mentioned what you just said to the hobby met who told me that. His web handle is CAPECaneCatcher31.
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Skyguy wrote:
Scott747 wrote:Where does he say anything about the track of 99l other than it potentially tracking towards the Lesser Antilles?

Might want to mention to your fellow 'hobby mets' that the HWRF has only ran once for 99l and also only goes out to 126 hrs, which not only puts it no where near Florida, but doesn't even it put it in the Caribbean. ;)
I'm sorry, I meant to say GFS. But they and I are concerned about what happens after it reaches the Lesser Antilles, as that is a dangerous place for TC formation. SHIPS intensity model, interestingly enough, predicts at least a Cat 1 storm prior to any interaction with the islands.

P.S. I have mentioned what you just said to the hobby met who told me that. His web handle is CAPECaneCatcher31.
Faster, stronger development would support a faster re-curve and more of a threat to the East Coast/Fish. There is a pretty strong weakness over the west central Atlantic. Still a long way out though. ECMWF still shows little to no development so that will be interesting to see if it trends toward the GFS.
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GFS is trending towards a more westerly track as the weakness from Fiona/trough is less defined over the western atlantic. Interesting to note the ECMWF still shows no development. This is definitely a system to keep an eye on in general.
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Andrew wrote:GFS is trending towards a more westerly track as the weakness from Fiona/trough is less defined over the western atlantic. Interesting to note the ECMWF still shows no development. This is definitely a system to keep an eye on in general.
Yeah I was telling Josh that if anything we should see a shift W with the models today with there being less weakness left from Fiona and the Euro had the energy moving through the Caribbean.

For now I think future Gaston gets into the Carribbean. Even so far out it will get interesting for the WGOM once it gets near Puerto Rico and we get a better handle on the track from there.
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Scott747 wrote:
Andrew wrote:GFS is trending towards a more westerly track as the weakness from Fiona/trough is less defined over the western atlantic. Interesting to note the ECMWF still shows no development. This is definitely a system to keep an eye on in general.
Yeah I was telling Josh that if anything we should see a shift W with the models today with there being less weakness left from Fiona and the Euro had the energy moving through the Caribbean.

For now I think future Gaston gets into the Carribbean. Even so far out it will get interesting for the WGOM once it gets near Puerto Rico and we get a better handle on the track from there.
The synoptic setup for that time period does show some interesting signs. I am not completely sold on the huge upper level low over the U.S. Northeast that the GFS is representing. The ECMWF has a lot more ridging over the east coast during that time. I agree that I think this will make it into the Caribbean.
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Skyguy

Andrew wrote:
Scott747 wrote:
Andrew wrote:GFS is trending towards a more westerly track as the weakness from Fiona/trough is less defined over the western atlantic. Interesting to note the ECMWF still shows no development. This is definitely a system to keep an eye on in general.
Yeah I was telling Josh that if anything we should see a shift W with the models today with there being less weakness left from Fiona and the Euro had the energy moving through the Caribbean.

For now I think future Gaston gets into the Carribbean. Even so far out it will get interesting for the WGOM once it gets near Puerto Rico and we get a better handle on the track from there.
The synoptic setup for that time period does show some interesting signs. I am not completely sold on the huge upper level low over the U.S. Northeast that the GFS is representing. The ECMWF has a lot more ridging over the east coast during that time. I agree that I think this will make it into the Caribbean.


I have a personal concern regarding 99L that I would like to share with this forum, Andrew.

Track will change because usually, models underestimate the Ridge. Personally, I think it will enter the Gulf due to a northward bias on all the models. It happened with Hurricane Isaac back in 2012. If I remember right, that one was originally expected to go out to see but instead ended up in Louisiana.

Then with Ike in 2008. He was supposed to hit the EC originally but instead ended up in Texas. Also Katrina was only supposed to hit the Florida east coast but instead went through Florida to then hit Louisiana and just this week with Fiona the GFS and some other reliable models not including the Euro showed Fiona when it was a invest curving out to sea at around 25 or 30 W. Models kept shifting west putting Bermuda in play

My conclusion: The huge northern bias with most of the model is due to terrible forecasting in ridging.

Your thoughts, Andrew?
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The afternoon updated Climate Prediction Center Day 8+ Analogs suggest a rather deep trough across the Central United States during the next 6 to 10 days with somewhat higher heights across the Eastern 1/3 of North America. It's certainly worth monitoring, but let's see what the situation looks like next week IF 99L develops and what the sensible upper air patterns actuality are later next week when this tropical disturbance nears the Lesser Antilles. While we are watching developments very closely, let's be mindful that our neighbors in Louisiana are still weary and suffering from the Major Flood Event of last weekend. We are very fortunate to have some of the best Tropical Weather Professionals as members of our KHOU Weather Forum as well as well over a couple of Centuries of combined experience with our Tropical Weather enthusiasts and Pro Mets. Stay tuned, and remember that our Online Weather Community is highly respected and has a longstanding tradition of providing folks across the Caribbean Sea and the Gulf Coast with the most accurate and reliable information possible...without the hype.
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Skyguy

Scott747 wrote:
Andrew wrote:GFS is trending towards a more westerly track as the weakness from Fiona/trough is less defined over the western atlantic. Interesting to note the ECMWF still shows no development. This is definitely a system to keep an eye on in general.
Yeah I was telling Josh that if anything we should see a shift W with the models today with there being less weakness left from Fiona and the Euro had the energy moving through the Caribbean.

For now I think future Gaston gets into the Carribbean. Even so far out it will get interesting for the WGOM once it gets near Puerto Rico and we get a better handle on the track from there.
Are you looking for a track similar to 2003's Hurricane Claudette, Scott?
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Skyguy wrote:
Scott747 wrote:
Andrew wrote:GFS is trending towards a more westerly track as the weakness from Fiona/trough is less defined over the western atlantic. Interesting to note the ECMWF still shows no development. This is definitely a system to keep an eye on in general.
Yeah I was telling Josh that if anything we should see a shift W with the models today with there being less weakness left from Fiona and the Euro had the energy moving through the Caribbean.

For now I think future Gaston gets into the Carribbean. Even so far out it will get interesting for the WGOM once it gets near Puerto Rico and we get a better handle on the track from there.
Are you looking for a track similar to 2003's Hurricane Claudette, Scott?
I can't speak for Scott myself, but I suspect that he isn't suggesting any track similarities so far. Too far out at this point. Models are all over the place and the impact on the numerous weaknesses over the western Atlantic paired with how fast (if?) this system spins up will be key. A lot of variables to consider ahead. As it stands right now I think all possibilities are in play so it's a wait and see game.
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Latest GFS suggests a lot weaker of a storm. Still a lot of model variability.
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I could come up with plenty of scenarios of where 99l would affect from Veracruz to OTS. Truth is I couldn't tell you with much certainty at this point in the game. Given that I would chase something with Josh in the WGOM, or help navigate for him if it impacted somewhere outside of this region, we toss around multiple scenarios.

Now with this being a local forum... 99l is so far out from having any possible threat to our area that for now it's just something to watch from afar. Tropical nerds shouldn't even mention it to the non weather enthusiasts because you would spend more time confusing them rather than accurately explaining it. That's why I mentioned Puerto Rico as sort of a way point. Once it gets in that general area we then can begin to start assessing any potential threat to our area, and even then it would still be so far out that any prediction would be low percentile.

Plenty of time to watch. Only prediction for now is it gets into the Caribbean and models will continue to flip flop in the longer range.
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latest 72-hr forecasts, with "X" at 96-hr surface

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GFS continues to trend towards the ECMWF solution of a weak storm/open wave. Beginning to think that shear, dry air, and the lack of the MJO influence will result in a trend towards the ECMWF solution. Still plenty of time to wait and see.
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The Atlantic Basin remains very active even though conditions are not ideal. The National Hurricane Center has tagged a very robust Tropical Wave exiting the West Coast of Africa as 90L.
two_atl_5d0 (8).png
TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
800 PM EDT SAT AUG 20 2016

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

The National Hurricane Center is issuing advisories on Tropical
Storm Fiona, located about 875 miles east-northeast of the Leeward
Islands.

1. A broad area of low pressure, associated with a tropical wave, is
located about midway between the west coast of Africa and the Lesser
Antilles. The associated shower activity remains disorganized, and
any development of this system during the next couple of days should
be slow to occur due to its large size and proximity to dry air.
Environmental conditions are forecast to be more conducive for
development beyond a couple of days, and a tropical depression could
form by the middle of next week while the system moves westward and
then west-northwestward at 15 to 20 mph across the tropical Atlantic
Ocean, through the eastern Caribbean Sea, and then near the Greater
Antilles.
* Formation chance through 48 hours...low...10 percent
* Formation chance through 5 days...medium...60 percent

2. A weak area of low pressure, associated with another tropical wave,
is moving off the coast of Senegal in western Africa while producing
a large area of cloudiness and thunderstorms. Environmental
conditions appear conducive for gradual development, and a tropical
depression is likely to form in a few days while the system moves
westward and then northwestward over the eastern tropical Atlantic
Ocean.
* Formation chance through 48 hours...low...30 percent
* Formation chance through 5 days...high...70 percent

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A lot of ridging along the US east coast forecasted in all the long range models being forced by upstream central US trough. Pattern favors E US ridge...note the drought conditions over the NE US. Will likely see extended range model tracks bend more left with time.

Big question is when if at all does 99L decide to develop. Looks like the favorable location would be in/near the Bahamas, but it could be sooner if the system tracks north of the big islands in the Antilles and it can flush out the dry air layer.
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Mimic clearly shows a lot of spin and moisture surrounding 99L as it moves generally West with little if any convection. Conditions look to become more favorable near Hispaniola and the SE Bahamas.

Not comparing this disturbance to anything close to Katrina, but I vividly remember while living in the Lower Keys in 2005, that the disturbance that would eventually spawn Katrina was surrounded by dry stable air into the Bahamas and then conditions improved and a Depression formed as it was heading generally W toward Florida and rapidly developed prior to the first landfall along the Miami Dade, Broward County line and dropped WSW over the Everglades into Florida Bay and it was off to the races with Rapid Intensification over the SE Gulf of Mexico.

Katrina August 2005
https://www.youtube.com/watch?v=jB7t4KKV38U

The latest 12Z ECMWF does show a slowing disturbance that intensifies into a Tropical Cyclone crossing Florida and near Mobile in the long range, for what it's worth.

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Yea the ECMWF shows development and is further west unlike the GFS which gets picked up by the east coast trough. Speed/timing are largely different between the two and makes all the difference. It will be concerning if east coast ridging develops as indicated by both models. Still a lot of variation in the models and little confidence in any one solution right now.
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srainhoutx i learn something new every day i did not know you lived in the Keys.That had to be an interesting place to live during hurricane season.
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cperk wrote:srainhoutx i learn something new every day i did not know you lived in the Keys.That had to be an interesting place to live during hurricane season.
It was certainly an experience leaving SE Texas for 5 years starting in June 2001 through April 2006 I will not forget, particularly during the 2004 and 2005 Hurricane Seasons. While it is a beautiful location, living on a small Island makes you realize just how vulnerable you are to the beasts we call Hurricanes. That is why when moving back home to Houston, we chose to be well inland from the Gulf Coast... ;)
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