EPAC: BONNIE - Post-Tropical - Discussion

[cycloneye]

 https://twitter.com/cyclonicwx/status/1541168790729261057

[Kingarabian]

Hot towers going off near the center. Looking a lot healthier compared to yesterday pre-DMAX.

[cycloneye]

It better start to gain some latitude because if it continues west, it will arrive at Guyana.

[cycloneye]

Central Tropical Atlantic:
Shower and thunderstorm activity associated with a tropical wave
located about 1000 miles east-southeast of the southern Windward
Islands has changed little in organization since earlier today.
However, environmental conditions appear conducive for development,
and a tropical depression is likely to form during the next few days
before the system reaches the Windward Islands Tuesday night or
while moving westward across the southern Caribbean Sea Wednesday
through Friday. Interests in the Windward Islands and along the
northeastern coast of Venezuela should monitor the progress of this
system, and tropical storm watches or warnings could be required for
portions of these areas on Monday. Regardless of development,
locally heavy rainfall is possible over the Windward Islands and the
northeastern coast of Venezuela Tuesday night and Wednesday.
* Formation chance through 48 hours...medium...60 percent.
* Formation chance through 5 days...high...80 percent.

[Hurricanehink]

It better start to gain some latitude because if it continues west, it will arrive at Guyana.

First ever Guyana landfall perhaps?

[Jr0d]

We shall see.

Rule #1

NEVER bet against Wxman57's calls.

This will not be a GoM storm!

[Hurricane Mike]

Video on 94L
https://www.youtube.com/watch?v=qksfSdX8vNU

[zzh]

[hipshot]

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

What the heck is that? Some sort of ASCAT?

[NXStumpy_Robothing]

We shall see.

Rule #1

NEVER bet against Wxman57's calls.

This will not be a GoM storm!

Let's not automatically elevate someone's predictions of a storm a week out to the word of God. Even the NHC, with some of the finest meteorologists in the world, busts on their forecasts. Considering that the system is still a nascent invest only on the cusp of TCG, the track and intensity are far from being set in stone. Besides, Rule #1 is "never say never in the tropics", please hand in your hurricane fanclub membership card when you leave

Anyway, back to the storm - this night's dmax might finally generate enough mid-level vorticity so that we can get constant convection near and over the center. Already starting to see popcorn convection springing up as we move away from dmin. Must be watched to see where this convection focuses as the elongated LLC shifts to a north-south orientation throughout the night, and if any other areas of persistent thunderstorm activity try to generate additional vorticity away from the current center. I personally expect the convection to focus around the northern end of the LLC/surface trough and attempt to pinch it off by late morning.

As for 94L's future, it's pretty clear in the ensembles and the deterministic runs alike that the sooner this system develops and begins strengthening, the further north the window of potential future tracks becomes. If we have a stronger storm than a model anticipates (or if they're the HWRF/GFS and verifying too far south), it's entirely possible that the system manages to impact the Yucatan Peninsula or even Western Cuba, especially when one also factors in the potential of the Gulf AOI developing and generating a weakness in the seemingly ever-present ridge across the Southeast. While the variables are easy to spot, the way that they will progress and affect one another is less so, and therefore I find it extremely difficult to claim that any part of the Western Caribbean/Gulf of Mexico/Bay of Campeche as being off-limits, especially since we're still so far out.

[ScottNAtlanta]

We shall see.

Rule #1

NEVER bet against Wxman57's calls.

This will not be a GoM storm!

Let's not automatically elevate someone's predictions of a storm a week out to the word of God. Even the NHC, with some of the finest meteorologists in the world, busts on their forecasts. Considering that the system is still a nascent invest only on the cusp of TCG, the track and intensity are far from being set in stone. Besides, Rule #1 is "never say never in the tropics", please hand in your hurricane fanclub membership card when you leave

Anyway, back to the storm - this night's dmax might finally generate enough mid-level vorticity so that we can get constant convection near and over the center. Already starting to see popcorn convection springing up as we move away from dmin. Must be watched to see where this convection focuses as the elongated LLC shifts to a north-south orientation throughout the night, and if any other areas of persistent thunderstorm activity try to generate additional vorticity away from the current center. I personally expect the convection to focus around the northern end of the LLC/surface trough and attempt to pinch it off by late morning.

As for 94L's future, it's pretty clear in the ensembles and the deterministic runs alike that the sooner this system develops and begins strengthening, the further north the window of potential future tracks becomes. If we have a stronger storm than a model anticipates (or if they're the HWRF/GFS and verifying too far south), it's entirely possible that the system manages to impact the Yucatan Peninsula or even Western Cuba, especially when one also factors in the potential of the Gulf AOI developing and generating a weakness in the seemingly ever-present ridge across the Southeast. While the variables are easy to spot, the way that they will progress and affect one another is less so, and therefore I find it extremely difficult to claim that any part of the Western Caribbean/Gulf of Mexico/Bay of Campeche as being off-limits, especially since we're still so far out.

Speaking of additional vorticity...there looks like some rotation on the NE side of the envelope. Around 45w 10n

[wxman57]

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

What the heck is that? Some sort of ASCAT?

It's the HY-2B scatterometer. Covers a larger area than ASCAT. There is a B and C channel:

https://scatterometer.knmi.nl/hy2b_25_prod/

[weeniepatrol]

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

What the heck is that? Some sort of ASCAT?

It's the HY-2B scatterometer. Covers a larger area than ASCAT. There is a B and C channel:

https://scatterometer.knmi.nl/hy2b_25_prod/

How reliable is this instrument? I thought some of the ASCAT cousins can be erroneous or over-enthusiastic. Admittedly don't know much about this one.

[wxman57]

Since NHC is predicting a high chance of development within 48 hrs, and if it was to develop into a TS within that 48 hours it would be impacting the islands within 48 hours, so a TS watch would be needed. If that's the case, then the NHC will begin issuing PTC advisories on "PTC Two" either at 9Z or 15Z.

[hipshot]

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

What the heck is that? Some sort of ASCAT?

It's the HY-2B scatterometer. Covers a larger area than ASCAT. There is a B and C channel:

https://scatterometer.knmi.nl/hy2b_25_prod/

Thanks, I think.

[Sciencerocks]

What's the odds of this making landfall in south America?

[cycloneye]

 https://twitter.com/FrankCarcaterra/status/1541249283076284416

[cheezyWXguy]

https://twitter.com/FrankCarcaterra/status/1541249283076284416

Kind of a sidebar, so apologies if this isn’t the best location for this topic, but I see a lot of posts with embedded tweets in them. I’ve seen opinions on this go either way, but I’m a fan of this trend. However, sometimes I see tweets posted here created by people I’m not familiar with, and its not always clear how “trustable” that person is. As one of the OG moderators on the board, do you think it would be a good idea to have people state whether the creator is a meteorologist, reputable amateur, or general amateur?

[Kingarabian]

Lot's of popcorn convection action. Overall circulation has tightened up with increased curvature.

[IsabelaWeather]

I just dont see how this is going to avoid SA right now. Its not gaining any latitude.