ATL: HARVEY - Post-Tropical - Discussion

[Dougiefresh]

anyone on islands what talk about 91 their ?as coould br area by friday

We are keeping an eye on it in Barbados but on the forecast track we might just get a little wet.

[Gustywind]

anyone on islands what talk about 91 their ?as coould br area by friday

we in the islands are watching VERY closely.

You're definitely RIGHT about that! We continue to monitor and keep an eye on this one carefully Msbee!
Regards.
Gustywind

[hurricanehunter69]

Just like 99l last week. 91l appears to be complex and elongated. The western lobe looked better yesterday, while the eastern lobe looks better today...per Mimic-TPW. It appears chances are growing that both may develop. The biggest difference between last week and this week though....Is that 91l has much more moisture and convection to work with. http://tropic.ssec.wisc.edu/real-time/m ... /main.html

[Gustywind]

anyone on islands what talk about 91 their ?as coould br area by friday

We are keeping an eye on it in Barbados but on the forecast track we might just get a little wet.

Hi my friend Anyway, especially all the Leewardians but even the Windwards islands and the whole EC islands should monitor very CLOSELY the situation during the next couple of days.

[cycloneye]

00z Best track.


AL, 91, 2017081500, , BEST, 0, 132N, 370W, 25, 1011, DB

[floridasun78]

anyone on islands what talk about 91 their ?as coould br area by friday

We are keeping an eye on it in Barbados but on the forecast track we might just get a little wet.

Hi my friend Anyway, especially all the Leewardians but even the Windwards islands and the whole EC islands should monitor very CLOSELY the situation during the next couple of days.

i heard could be close to you all by Friday

[floridasun78]

that is so big tropical wave will take time to form low that big mess what going for it that not moving fast dry air not bad other system we seen this year look shears this time not issue other other system but not sure how shear in eastern Caribbean not look yet that been issue past system

[Gustywind]

We are keeping an eye on it in Barbados but on the forecast track we might just get a little wet.

Hi my friend Anyway, especially all the Leewardians but even the Windwards islands and the whole EC islands should monitor very CLOSELY the situation during the next couple of days.

i heard could be close to you all by Friday

Maybe, you're right... that's why us in the EC islands must be on our guard but we're a bit far away from a real threat for the moment. Let's wait and see.

[Steve]

Just like 99l last week. 91l appears to be complex and elongated. The western lobe looked better yesterday, while the eastern lobe looks better today...per Mimic-TPW. It appears chances are growing that both may develop. The biggest difference between last week and this week though....Is that 91l has much more moisture and convection to work with. http://tropic.ssec.wisc.edu/real-time/m ... /main.html

I don't know. I don't think they both develop though we did have that year with the couple of side-by-side twin systems in the Atlantic (14?) and Pacific. That's a big surge on mimic. The dry low out in front of it has been massive since it was still in Africa. Down the road, it represents possible ventilation based on its position the NW Quadrant of the two systems. I guess best bet a week+ out is that something consolidates more toward the big islands or near Central America. The dry low isn't that dry anymore (also per MIMIC) and should blast the way ahead. It most likely stays moving west. Maybe 91L follows or maybe it gains latitude. The ECMWF has trended from just South of S FL to Central America. It's not getting much latitude on it. I don't see anything on the models yet that would slow 91L down later or cause it to take on some type of a northward component. I think a trough pulls out a couple days ahead, so it may just keep on cruising without developing much. On the other hand, if it finds a way to get up into the SW Atlantic, NW Caribbean or Gulf, I think this would have the chance to be a big and bad storm. There are a lot of possibilities.

[wxman57]

It doesn't look as impressive as earlier today. I'm beginning to think only a very small chance of development east of the Caribbean.

[Gustywind]

Atlantic Invest 91L May Become the Next Tropical Storm; Potential Threat for Lesser Antilles Late This Week
By Chris Dolce
Aug 14 2017 08:00 PM EDT
weather.com
https://weather.com/storms/hurricane/ne ... ugust-2017


An area of disturbed weather in the eastern tropical Atlantic Ocean, Invest 91L, is being monitored for development.

This system should pass near the Lesser Antilles late this week or this weekend.

It is too soon to determine its potential future track next week.

Another system to the east of Invest 91L is also being watched for tropical development.

An area of disturbed weather in the eastern Atlantic Ocean may develop into the next tropical depression or tropical storm later this week and may eventually pose a threat to the Lesser Antilles by the weekend.
This tropical disturbance has been dubbed Invest 91L by the National Hurricane Center (NHC). The term "invest" is used to identify features that have a chance to develop into a tropical depression or tropical storm.
For now, the NHC has given this system a medium chance of development during the next five days. Those odds could increase in the days ahead, however.
Invest 91L is producing a robust area of shower and thunderstorm activity as it moves westward to the southwest of the Cabo Verde Islands.

The environment around the broad area of low pressure is fairly moist, which could help aid in its ability to continue generating concentrated shower and thunderstorm activity if the area of storminess can consolidate.
Overall, the NHC says that environmental conditions are generally conducive to development in the days ahead as it moves westward.

The good news is that we have plenty of time to monitor the progress of Invest 91L since it's not expected to reach the longitude of the Lesser Antilles until Friday or Saturday.

It is far too early to determine any impacts on those islands or any other location farther down the road since there is uncertainty surrounding this system's exact future track and strength.

If this system eventually has impact in the U.S., it wouldn't be until sometime next week.

This uncertainty is typical for this far out in time, particularly when a tropical cyclone has yet to develop.

The NHC is also watching another area in the tropical Atlantic for development. This system is located to the east of Invest 91L but will be monitored for development in the days ahead. Just like 91L, there is plenty of time to monitor its progress, and it is too soon to determine its potential future track.
The bottom line is that we are in the climatological peak of the hurricane season, so each tropical wave or area of low pressure in the Atlantic Basin must be watched closely for development. As the image to the right shows, named storms can form in about every part of the Atlantic Basin this time of year.

As an example, the disturbance that formed into Tropical Storm Gert to the northeast of the Bahamas over the weekend was tracked for nearly 10 days before it finally developed. That tropical wave also originated near the African coast.

That said, not all tropical waves or low-pressure systems that emerge from Africa become tropical depressions or tropical storms, but they are all monitored closely, particularly when atmospheric conditions are ripe for them to spin up.

The next named storm will be called "Harvey."
Now is a good time to make sure you have a plan in case of a hurricane strike. The Federal Alliance for Safe Homes has an excellent website to help you make your plan.

Check back with weather.com for updates in the days ahead on these latest systems and the rest of hurricane season.

[Gustywind]

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
739 PM EDT Mon Aug 14 2017


A tropical wave extends from 22N25W to 13N27W moving W at 10-15
kt. The wave coincides with 700 mb troughing between 21W-29W and a
maximum in 850 mb relative vorticity at the southern extent of
the wave near 13N27W. The wave is expected to inject energy into
a 1011 mb low embedded within the monsoon trough near 13N35W by
Tuesday. Environmental conditions are expected to become more
conducive for development of this low later in the week with a
medium chance for tropical cyclone formation within 5 days. Widely
scattered moderate convection is from 11N-15N between 26-33W.

[Andrew92]

Definitely one to watch, though I don't think it develops right away. My gut tells me this develops closer to the Lesser Antilles, or maybe in the Caribbean itself.

However, I am concerned if it forms where I sense it might. I haven't seen entirely how favorable or unfavorable conditions for develop and/or intensification are in the Caribbean, but if Franklin and what the western Caribbean are know for are any indications, it's certainly one to monitor closely further west in time.

But we'll cross that bridge when we get there. For now, just monitoring, hopefully nothing significant comes out of this. It is just about that time of year though, and if nothing else, I think this plus Franklin and Gert combined are at least a wake-up call to be ready for the peak of the season.

-Andrew92

[AubreyStorm]

Just like 99l last week. 91l appears to be complex and elongated. The western lobe looked better yesterday, while the eastern lobe looks better today...per Mimic-TPW. It appears chances are growing that both may develop. The biggest difference between last week and this week though....Is that 91l has much more moisture and convection to work with. http://tropic.ssec.wisc.edu/real-time/m ... /main.html

Elongated? Hmmmm

http://tropic.ssec.wisc.edu/real-time/a ... wg8vor.GIF

[blp]

Just like 99l last week. 91l appears to be complex and elongated. The western lobe looked better yesterday, while the eastern lobe looks better today...per Mimic-TPW. It appears chances are growing that both may develop. The biggest difference between last week and this week though....Is that 91l has much more moisture and convection to work with. http://tropic.ssec.wisc.edu/real-time/m ... /main.html

Elongated? Hmmmm

http://tropic.ssec.wisc.edu/real-time/a ... wg8vor.GIF

I was going to post on this. First time we see the two vorticities separated. Very important sign that indeed both areas will develop.

[tropicwatch]

The rotation with the eastern convection looks impressive this morning.

[GCANE]

15N 40W looks good.
Strong convection zipping across LL convergence line.
Nicely developed 850mb and 700mb vorts.

[Emmett_Brown]

As some have said already, it looks as if both these areas are slowly developing. I would think we might see another invest declared on the wave near 32W soon. Add the system just leaving Africa, and the 06z GFS actually looks pretty plausible, with all 3 systems developing to varying extents. 91L is sporting a flat top/mullet of some sort this morning, as the circulations collide and stretch out along the trough.

[cycloneye]

8 AM TWO down to 20%-40%

An elongated area of low pressure located more than a thousand
miles east of the Lesser Antilles is producing disorganized showers
and thunderstorms. This system is expected to move westward at 15
to 20 mph across the tropical Atlantic Ocean, crossing into the
Caribbean Sea on Friday. Environmental conditions appear somewhat
supportive of tropical cyclone formation over the next few days
but should become less favorable once the system moves into the
Caribbean Sea.
* Formation chance through 48 hours...low...20 percent.
* Formation chance through 5 days...medium...40 percent.

[GCANE]

Kinda like a Venn Diagram