NATL: MELISSA - Hurricane - Discussion

[Nimbus]

2:00 PM EDT Sat Oct 25
Location: 16.6°N 75.2°W
Moving: WNW at 1 mph
Min pressure: 980 mb
Max sustained: 75 mph

.1 degree N of 11am and was predicted to move .1 degrees S before W turn. May change angle towards Jamaica?

Depends on how you smooth the trochoidal motion.

[cycloneye]

18z Best Track up to 75kt.

AL, 13, 2025102518, , BEST, 0, 165N, 752W 75, 976,HU

[HurricaneAndre2008]

AL, 13, 2025102518, 01, CARQ, 0, 165N, 752W, 75, 976, HU, 64, NEQ, 15, 10, 10, 15, 1007, 150, 10, 0, 0, L, 0, X, 285, 2, MELISSA, D,

[Iceresistance]

I think Melissa has gotten the dual VHTs, the arrows are direction. The northern VHT is moving fast

https://s12.gifyu.com/images/b3n30.png

[TomballEd]

The 12z HAFS-B and A solution would be near-worst case scenarios for the Kingston area, with the core either just to the left or into the harbor.

Also, I did not know that Kingston's international airport is essentially in the middle of the harbor. Seems like a pretty bad place for an airport.

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

https://i.imgur.com/pM4efzy.png

https://i.imgur.com/jUbxyTc.jpeg

3 m elevation per Wiki. Airport on the site of the old city of Port Royal which settled into the bay during the 1692 earthquake.

[Teban54]

Edit: This was written before the most recent Best Track update to 75 kts.

Now that Melissa is officially a hurricane at 2pm ET, I got curious and looked at rates of intensification for Cat 5s, starting from the last time step they remained at 70 kts or lower. (For example, Erin 2025 spent 12 hours at 65 kt, which wasn't counted.)

I'm using "70 kt or lower" as the threshold for "minimum Cat 1", both because some storms jump from TS to this intensity (skipping 65 kt), and because low-end and high-end Cat 1s often display different organizational progress for further intensification.

TL;DR: A top-tier intensification rate (like Wilma, Milton and Erin) can bring Melissa to Cat 5 in the next 18-24 hours. But it's still very plausible to get a Cat 5, even without pinhole eyes, with a "normal" rate of 1.5-2 days. With almost 3 days before landfall, there's more than enough time.

Storms that intensified from 70- kt (low Cat 1) to 140+ kt (Cat 5) within 48 hours

• Wilma 2005: 18 hours, 65 -> 150 kt (12z 10/18/05 to 06z 10/19/05)
• Erin 2025: 18 hours 20 minutes, 65 -> 140 kt (21z 8/15/25 to 15:20z 8/16/25)
• Felix 2007: 24 hours, 65 -> 150 kt (00z 9/2/07 to 00z 9/3/07)
• Milton 2024: 24 hours, 70 -> 150 kt (18z 10/6/24 to 18z 10/7/24)
• Matthew 2016: 24 hours, 70 -> 145 kt (00z 9/30/16 to 00z 10/1/16) - debated
• Andrew 1992: 30 hours, 65 -> 145 kt (06z 8/22/92 to 12z 8/23/92)
• Maria 2017: 30 hours, 65 -> 145 kt (18z 9/17/17 to 00z 9/19/17)
• Edith 1971: 30 hours, 65 -> 140 kt (12z 9/8/71 to 18z 9/9/71)
• Lee 2023: 30 hours, 70 -> 145 kt (00z 9/7/23 to 06z 9/8/23)
• Rita 2005: 30 hours, 70 -> 145 kt (12z 9/20/05 to 18z 9/21/05)
• "Labor Day" 1935: 36 hours, 65 -> 160 kt (12z 9/1/35 to 00z 9/3/35) - data issue, likely took much less time in reality
• Camille 1969: 36 hours, 65 -> 150 kt (06z 8/15/69 to 18z 8/16/69) - with intermediate weakening
• Humberto 2025: 36 hours, 65 -> 140 kt (09z 9/26/25 to 21z 9/27/25)
• Janet 1955: 41 hours, 70 -> 140 kt (00z 9/26/55 to 17z 9/27/55)
• "Tampico" 1933: 42 hours, 70 -> 140 kt (06z 9/19/33 to 00z 9/21/33)
• Allen 1980: 42 hours, 70 -> 140 kt (06z 8/3/80 to 00z 8/5/80)
• Hugo 1989: 42 hours, 70 -> 140 kt (00z 9/14/89 to 18z 9/15/89)
• Dean 2007: 48 hours, 70 -> 145 kt (06z 8/16/07 to 06z 8/18/07)
• Ian 2022: 48 hours, 70 -> 140 kt (12z 9/26/22 to 12z 9/28/22) - with intermediate weakening
• Beryl 2024: 48 hours, 70 -> 140 kt (00z 6/30/24 to 00z 7/2/24) - with intermediate weakening
• Anita 1977: 48 hours, 70 -> 140 kt (00z 8/31/77 to 00z 9/2/77)

Uses advisory times for 2025, and TCR for others (ignoring intermediate times unless in the TCR).

[Teban54]

I think Melissa has gotten the dual VHTs, the arrows are direction. The northern VHT is moving fast
https://s12.gifyu.com/images/b3n30.png
https://s12.gifyu.com/images/b3n30.png

Now it looks like there are even 3 hot towers:

[Zonacane]

I think Melissa has gotten the dual VHTs, the arrows are direction. The northern VHT is moving fast
https://s12.gifyu.com/images/b3n30.png
https://s12.gifyu.com/images/b3n30.png

Now it looks like there are even 3 hot towers:

https://i.imgur.com/UJ1rnpo.gif

I spy a fast-moving 4th tower on the left. You can spot the shadow it is casting

[Kazmit]

Eye is starting to pop out on both visible and IR

[TomballEd]

I think Melissa has gotten the dual VHTs, the arrows are direction. The northern VHT is moving fast
https://s12.gifyu.com/images/b3n30.png
https://s12.gifyu.com/images/b3n30.png

Now it looks like there are even 3 hot towers:

https://i.imgur.com/UJ1rnpo.gif

Watching that loop out another 8 minutes I may or may not be seeing the first sign of the dimple that becomes the satellite visible eye.

[StormWeather]

Tbh this storm may be closing in on Category 2 intensity already, but we will see.

[BobHarlem]

https://x.com/cfhc/status/1982175383253 ... ZdlrQ&s=19

 https://x.com/cfhc/status/1982175383253352953

[CrazyC83]

I'd go with 80 kt for the advisory, although that is an uncertain estimate and Recon may find something much stronger. We may be playing catchup with special advisories tonight.

[Gladstone]

https://i.imgur.com/jUbxyTc.jpeg

Probably the worst place you could choose for a major airport in a hurricane-prone area.

Remember Sim City? That island is the perfect spot for an airport or power plant.

[aspen]

Tbh this storm may be closing in on Category 2 intensity already, but we will see.

I kinda doubt it. While the eyewall on radar is getting better, actual convection is still a little lacking. Likely a mid to upper end Cat 1, though. Cat 2 will likely be achieved once those rotating hot towers sustain themselves a little more.

[USTropics]

I think Melissa has gotten the dual VHTs, the arrows are direction. The northern VHT is moving fast
https://s12.gifyu.com/images/b3n30.png
https://s12.gifyu.com/images/b3n30.png

Definitely some VHTs induced by the dry air interaction with the moist profile of Melissa's improving inner core:


We have some dry air entrainment as Melissa starts to expand her convective envelope. Meanwhile, we have this moist inner core developing which has high equivalent potential temperature (PT). This creates these localized boundaries where inflow basically hits a wall, and we get enhanced convergence when the dry air hits the moist inflow (environment PT decreases, parcel buoyancy increases), and rapid ascent of warm, moist air takes place (our VHTs).

Each point where the dry air "hits" the moist core can initiate a separate updraft. The red VHT is optimally positioned so it has the largest vertical ascent initially. As teal continues to rotate towards the north, it gets more of those direct localized enhanced convergence effects. This is the response to balance two things: (1) the asymmetric structure that Melissa currently exhibits and (2) as a means to mix out the dry air intrusion before it reaches the inner core and disrupts the eyewall formation cycle.

[zzzh]

NHC calls for a 140kt cat 5 peak!

[NDG]

 https://x.com/NDGMETCHEF/status/1982190667842437507

[Sciencerocks]

[HurricaneAndre2008]

The latest on Hurricane Melissa!!

https://youtu.be/9F41gUjFu1E?si=QzCekCUhbZZZlOk2