NATL: IMELDA - Post-Tropical - Discussion

[cycloneye]

18z Best Track:

AL, 94, 2025092618, , BEST, 0, 207N, 744W, 30, 1008, DB

[Blown Away]

I would say this still a strong wave and is just clearing land interactions.
This convective blow up is a good sign something is trying to form,

Where would you put the most likely area for it to form now? Would it be farther NW than the 12Z position?

Maybe somewhere west of the island ~21.5N 74.5W around early Saturday morning.
What are your thoughts?

As long as I see those low level clouds continue moving W I don’t know why the NHC “X” won’t continue W to WNW. That NHC “X” was swung from E to W over past 5 advisories without gaining much latitude.

[boca]

Where would you put the most likely area for it to form now? Would it be farther NW than the 12Z position?

Maybe somewhere west of the island ~21.5N 74.5W around early Saturday morning.
What are your thoughts?

As long as I see those low level clouds continue moving W I don’t know why the NHC “X” won’t continue W to WNW. That NHC “X” was swung from E to W over past 5 advisories without gaining much latitude.

That cold front is advancing SE cutting across the Gulf thru N Florida and I would think 94L would hits brick wall and turn NNW very soon.

[wxman57]

I get the point of expecting a PTC, but some of y’all are acting like NHC is trying to keep this from people when they are very specific every 6 hours with a a TWO that details their expectations and warns people in the path. It would be nice for more clarity on why/when the issue PTCs… but they have other tools and perhaps they’ve received feedback that the PTC seems unnecessary. *shrug*

I can see why the NHC would want to wait. People focus on the center of the cone all the time typically. With this level of uncertainty, the initial forecast has a high probability of being wrong. The winds in the Bahamas are looking to be TS force or lower so waiting a model run or two longer to see if the forecast improves seems reasonable to prevent either premature panic or people writing off the threat too soon.

I expect they will issue PTC advisories by 5 pm or 11 pm at the latest if a TD hasn’t formed by then.

Yes, there it too much uncertainty to issue a track and suggest another Helene for the Carolinas. They have the luxury of waiting until there is better model agreement. Heavy rain for the Bahamas this weekend, but not too much wind.

[Steve]

Accuweather

https://youtu.be/tCVyyJLYww0?si=x2nkHXHLkymx1mxc

Bernie misnaming his video feature. No clarity there.

[Teban54]

[Nimbus]

The center is becoming more noticeable as it consolidates north of the eastern tip of Cuba.
I think the center has been moving WNW since Gonave island.

[zzzh]

AL, 09, 2025092618, , BEST, 0, 207N, 744W, 30, 1008, DB,

Likely a PTC at 5.

[cycloneye]

NHC will initiate advisories on Potential Tropical Cyclone Nine (formerly AL94), located near eastern Cuba, at 500 PM EDT (2100 UTC).

[TampaWxLurker]

That's quite the spread on the cone at 5 days on the first NHC map, but it makes a lot of sense considering the high uncertainty.

Kind of reminds me of the giant cones from 20+ years ago back when I started paying attention to such things during the 2004 season.

[KPILM]

Man, I sure hope this thing doesn't stall and dump rain for days. I could go the rest of my life without another Florence.

[Teban54]

That's quite the spread on the cone at 5 days on the first NHC map, but it makes a lot of sense considering the high uncertainty.

Kind of reminds me of the giant cones from 20+ years ago back when I started paying attention to such things during the 2004 season.

This is a common misconception. In any given year and for any given forecast point (e.g. 120 hrs), the size of the cone for all storms and all advisories are always the same. It's merely a statement about historical forecast accuracy: "In past years, a storm's 120 hrs forecast point has a 67% chance of making an error this large". It does NOT capture anything storm-specific, including its own uncertainties.

[psyclone]

That's quite the spread on the cone at 5 days on the first NHC map, but it makes a lot of sense considering the high uncertainty.

Kind of reminds me of the giant cones from 20+ years ago back when I started paying attention to such things during the 2004 season.

Conse size doesn't change with uncertainty...although one could make an argument it should. cones look fatter with a slower motion. in fact..if we slow the system down enough...a cone will morph into a circle...which is wildly cool..

[wxman57]

The NHC day 5 point is 36 hrs slower than all guidance. They appear to not want to commit to a landfall. I've seen them do that for decades. No need to cause panic until they're more sure of a possible landfall. We don't have that luxury. Wish we did, as I don't know if it's moving inland. We have it moving inland by sunrise Tuesday. NHC has it well offshore Wednesday afternoon. Some of our clients are asking if this will be another Helene. I'm sure the NHC has those concerns.

[IcyTundra]

That's quite the spread on the cone at 5 days on the first NHC map, but it makes a lot of sense considering the high uncertainty.

Kind of reminds me of the giant cones from 20+ years ago back when I started paying attention to such things during the 2004 season.

As far as I know the cone is the same size for all tropical cyclones.

[invest man]

The NHC day 5 point is 36 hrs slower than all guidance. They appear to not want to commit to a landfall. I've seen them do that for decades. No need to cause panic until they're more sure of a possible landfall. We don't have that luxury. Wish we did, as I don't know if it's moving inland. We have it moving inland by sunrise Tuesday. NHC has it well offshore Wednesday afternoon. Some of our clients are asking if this will be another Helene. I'm sure the NHC has those concerns.

How about a type of Florence redo?

[wxman57]

That's quite the spread on the cone at 5 days on the first NHC map, but it makes a lot of sense considering the high uncertainty.

Kind of reminds me of the giant cones from 20+ years ago back when I started paying attention to such things during the 2004 season.

As far as I know the cone is the same size for all tropical cyclones.

The cone is made by plotting a series of circles at each track point. Each circle represents that the center tracked within that circle 67% of the time over the past five seasons. It's the same for every advisory and every storm in a season. It looks odd when the storm doesn't move for 24 hours. Normally, the 120 hours point would be 200-300 miles away from the 96 hour point and you'd just see the cone getting wider at the end.

[tolakram]

saved loop


source: https://weather.cod.edu/satrad/?parms=local-Turks_and_Caicos-02-24-0-50-1&checked=map&colorbar=undefined

[ConvergenceZone]

The forecast has this briefly as a Cat 1 but then back down to a tropical storm. The conditions to prevent this from strengthening much must be very brutal. Good news for wind, but still bad news for rain if this stall does happen.

[eastcoastFL]

Looks like NHC has this thing stalling out off of the Carolina coast. It goes absolutely nowhere from 2pm Tuesday to 2pm Wednesday.