Low pressure trough east of the Bahamas (Is Invest 98L)

[cycloneye]

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
100 PM EST Sun Nov 3 2024

Southwestern Atlantic:
An area of disturbed weather is expected to develop near the
northern Leeward Islands around the middle of the week. Some slow
development of this system is possible after that time as it moves
generally westward over the southwestern Atlantic.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 7 days...low...20 percent.

\

[cycloneye]

7 PM EST.

Southwestern Atlantic:
An area of disturbed weather could develop from an interaction of
moisture with an upper-level trough digging near the northern
Leeward Islands around the middle of this week. Some slow
subtropical or tropical development of this system is possible after
that time as it moves generally westward over the southwestern
Atlantic.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 7 days...low...20 percent.

[gatorcane]

18Z GFS track, into the Bahamas and the FL straits after that:

[cycloneye]

Southwestern Atlantic:
An area of low pressure could develop near the northern Leeward
Islands in a few days. Some slow development of this system is
possible after that time as it moves generally westward over the
southwestern Atlantic.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 7 days...low...20 percent.

[underthwx]

Southwestern Atlantic:
An area of low pressure could develop near the northern Leeward
Islands in a few days. Some slow development of this system is
possible after that time as it moves generally westward over the
southwestern Atlantic.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 7 days...low...20 percent.

Is this the system that may be absorbed by Rafael?

[cycloneye]

Southwestern Atlantic:
An area of low pressure could develop near the northern Leeward
Islands in a few days. Some slow development of this system is
possible after that time as it moves generally westward over the
southwestern Atlantic.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 7 days...low...20 percent.

Is this the system that may be absorbed by Rafael?

Not this one.

[cycloneye]

Southwestern Atlantic:
A trough of low pressure is producing disorganized showers and
thunderstorms east-northeast of the Leeward Islands. Portions of
this system are forecast to move westward during the next day or so
and could form a low pressure near the northern Leeward by Thursday.
Afterward, some slow development of this system is possible during
the latter part of the week while it moves generally westward over
the southwestern Atlantic.
* Formation chance through 48 hours...low...10 percent.
* Formation chance through 7 days...low...30 percent.

[Blown Away]

The NHC "X" is near 22N/54W and it appears to be a low developing...

[cycloneye]

1. Southwestern Atlantic:
An elongated trough of low pressure is producing disorganized
showers and thunderstorms several hundred miles east-northeast of
the Leeward Islands. A portion of this system is forecast to begin
moving westward by early Wednesday, and an area of low pressure
could form near the northern Leeward Islands by Wednesday night.
Afterward, some slow development of this system is possible during
the latter part of the week while it moves generally westward,
passing near or north of the Virgin Islands and Puerto Rico on
Thursday, and approaching the Southeast Bahamas by Friday.
* Formation chance through 48 hours...low...20 percent.
* Formation chance through 7 days...low...30 percent.

[cycloneye]

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
700 AM EST Wed Nov 6 2024

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

Active Systems:
The National Hurricane Center is issuing advisories on Hurricane
Rafael, located over the northwest Caribbean Sea.

1. Southwestern Atlantic:
A trough of low pressure is producing an area of disorganized
showers and thunderstorms several hundred miles east-northeast of
the Leeward Islands. This system is expected to move generally
westward during the next few days, and an area of low pressure could
form near the northern Leeward Islands tonight or Thursday.
Afterward, some gradual development of this system is possible
toward the end of the week and into the early part of the weekend
while it moves near or to the north of the Virgin Islands and
Puerto Rico, and approaches the Southeast Bahamas.
* Formation chance through 48 hours...low...20 percent.
* Formation chance through 7 days...low...30 percent.


Forecaster Bucci

[cycloneye]

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
700 PM EST Wed Nov 6 2024

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

Active Systems:
The National Hurricane Center is issuing advisories on Hurricane
Rafael, located near the north coast of western Cuba.

Southwestern Atlantic:
A trough of low pressure is producing an area of disorganized
showers and thunderstorms a couple hundred miles east-northeast of
the northern Leeward Islands. This system is expected to move
generally westward during the next few days, and an area of low
pressure could form near the northern Leeward or Virgin Islands
tonight or Thursday. Afterward, some gradual development of this
system is possible toward the end of the week and into the weekend
while it moves near or to the north of the Virgin Islands and Puerto
Rico, and approaches the Southeast Bahamas.
* Formation chance through 48 hours...low...20 percent.
* Formation chance through 7 days...low...30 percent.

$$
Forecaster Hagen

[Emmett_Brown]

Starting to look invest worthy

[cycloneye]

Near the Leeward Islands:
A trough of low pressure over the northern Leeward Islands continues
to produce disorganized showers and thunderstorms. Some gradual
development of this system is possible during the next couple of
days while it moves westward near the Greater Antilles. Regardless
of development, locally heavy rains are possible across the northern
Leeward Islands, the Virgin Islands, Puerto Rico, Hispaniola, and
the southeastern Bahamas through Saturday.
* Formation chance through 48 hours...low...20 percent.
* Formation chance through 7 days...low...20 percent.

[Blown Away]

Very broad and disorganized, but it has a swirl developing...

[boca]

[url]https://i.postimg.cc/N0fxPBxd/b822148e-044d-4447-9356-afeca17de257.gif [/url]
Very broad and disorganized, but it has a swirl developing...

Do you think it will make it to Florida this time of year?

[chaser1]

NHC lowered the prior 20/30 development probabilities to 20/20. I think in part this may be due to the concentration of convection and possible competing inflow from the flare up just south of Puerto Rico. I think both areas are broadly associated which in itself hinders consolidation. Secondly of course are the Greater Antilles land masses too. Perhaps the southernmost feature might become the primary focal point as it slides westward if it can remain south of Cuba. On the other hand upper air forecast conditions appear primarily cyclonic aloft however, so it seems improbable that we'd see development out of this feature either.

[AJC3]

https://i.postimg.cc/N0fxPBxd/b822148e-044d-4447-9356-afeca17de257.gif
Very broad and disorganized, but it has a swirl developing...

This visible loop is also a great example of what's called (in fluid mechanics) a vortex sheet roll-up. I've seen this dozens, if not hundreds of times in the subtropics along stalled fronts, where the large scale discontinuity in flow on opposite sides of a stalled, W-E oriented front leads to multiple vortices developng along the decaying boundary. Generally, you have E-ENE in place on one side immediately opposing W-WSW flow on the other when this starts to occur. In this case, it looks like the flow south of what's left of the boundary is quite light, which is still sufficient for a vortex roll-up to take place.

I have a great satellite example of this occurring over Florida and the adjacent GOMEX/ATLC about ~20 years ago.

These features are usually weak/strung out, however, sometimes this happens within monsoon troughs, particularly over the equatorial WPAC, and can lead to the development of multiple TCs when the trough is convectively active.

[cycloneye]

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
100 PM EST Thu Nov 7 2024

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

Active Systems:
The National Hurricane Center is issuing advisories on Hurricane
Rafael, located over the southeastern Gulf of Mexico.

1. Near the Leeward Islands:
A trough of low pressure over the northern Leeward Islands continues
to produce disorganized showers and thunderstorms. Some gradual
development of this system is possible during the next couple of
days while it moves westward near the Greater Antilles. Regardless
of development, locally heavy rains are possible across the northern
Leeward Islands, the Virgin Islands, Puerto Rico, Hispaniola, and
the southeastern Bahamas through Saturday.
* Formation chance through 48 hours...low...20 percent.
* Formation chance through 7 days...low...20 percent.


Forecaster Bucci

[underthwx]

This visible loop is also a great example of what's called (in fluid mechanics) a vortex sheet roll-up. I've seen this dozens, if not hundreds of times in the subtropics along stalled fronts, where the large scale discontinuity in flow on opposite sides of a stalled, W-E oriented front leads to multiple vortices developng along the decaying boundary. Generally, you have E-ENE in place on one side immediately opposing W-WSW flow on the other when this starts to occur. In this case, it looks like the flow south of what's left of the boundary is quite light, which is still sufficient for a vortex roll-up to take place.

I have a great satellite example of this occurring over Florida and the adjacent GOMEX/ATLC about ~20 years ago.

These features are usually weak/strung out, however, sometimes this happens within monsoon troughs, particularly over the equatorial WPAC, and can lead to the development of multiple TCs when the trough is convectively active.

https://i.imgur.com/tMaSQYq.png

Oh wow! That is too cool for school! I see the multiple vortices you highlighted with the yellow x's. Is the bigger area of clouds in the front, part of these multiple vortices ?

[ChrisH-UK]

A broad rotation is starting to setup with the centre been south Hispaniola and Puerto Rico.