NATL: MELISSA - Hurricane - Discussion

[GCANE]

 https://x.com/JamaicaObserver/status/1982109709982150875

[cheezyWXguy]

I’m not sold on the contraction to pinhole eye though, that eye looks about average sized. Good news is that probably means a Milton or Wilma-level explosion isn’t as likely, but bad news is a larger core won’t collapse as quickly into an ewrc upon reaching peak. Could still undergo one, but would probably stabilize for a while first. Won’t matter much either way though, it’s hard to bet against a cat5 peak at this point so Jamaica better be taking this seriously

[GCANE]

Not going to see an eye for a while.
Cirrus spewing from the hot towers will obscure it.
Probably a high-end Cat 1 within the hour.

[cycloneye]

I’m not sold on the contraction to pinhole eye though, that eye looks about average sized. Good news is that probably means a Milton or Wilma-level explosion isn’t as likely, but bad news is a larger core won’t collapse as quickly into an ewrc upon reaching peak. Could still undergo one, but would probably stabilize for a while first. Won’t matter much either way though, it’s hard to bet against a cat5 peak at this point so Jamaica better be taking this seriously

The worse part is that it will move very slow to prolong the effects for 48 hours or more on the island.

[ScottNAtlanta]

Radar is showing a west movement
https://zoom.earth/places/jamaica/#map=radar

[MHC Tracking]

Usually when a strong RI occurs a EWRC quickly ensues right after.
Wonder if one will be underway before Jamaica.
Praying that it does.

An EWRC would likely exacerbate the situation by broadening the radius of hurricane-force winds and in turn increasing surge

[MHC Tracking]

I’m not sold on the contraction to pinhole eye though, that eye looks about average sized. Good news is that probably means a Milton or Wilma-level explosion isn’t as likely, but bad news is a larger core won’t collapse as quickly into an ewrc upon reaching peak. Could still undergo one, but would probably stabilize for a while first. Won’t matter much either way though, it’s hard to bet against a cat5 peak at this point so Jamaica better be taking this seriously

I'm not "downcasting" but I remain a bit doubtful of a Cat 5 peak. Downsloping from Jamaica has interfered with the development of hurricanes in the past (see: Grace 2021), it feels possible that it does so here as well.

[BobHarlem]

Jamaica radar loop

[Iceresistance]

Tower is tightening up the eyewall
Likely a pinhole in 24 hrs.

https://metservice.gov.jm/daily-forecast/radar/

Can you post the radar image for me? I can't see it for some reason

[Beef Stew]

There it is. We officially have Hurricane Melissa.

[HurricaneRyan]

Here we go

[Nimbus]

Radar is showing a west movement
https://zoom.earth/places/jamaica/#map=radar

NHC is blending the ECM track a little, the 2 PM NHC update still reporting a WNW motion.
Could be a wobble or start of a new 6 hour motion, the sooner the west turn comes the better for Kingston.
Current forecast would put Kingston in the core winds for about 24 hours starting around Monday noon.
Mostly focusing on the flooding potential which is a much larger area.

[USTropics]

I’m not sold on the contraction to pinhole eye though, that eye looks about average sized. Good news is that probably means a Milton or Wilma-level explosion isn’t as likely, but bad news is a larger core won’t collapse as quickly into an ewrc upon reaching peak. Could still undergo one, but would probably stabilize for a while first. Won’t matter much either way though, it’s hard to bet against a cat5 peak at this point so Jamaica better be taking this seriously

I'm not "downcasting" but I remain a bit doubtful of a Cat 5 peak. Downsloping from Jamaica has interfered with the development of hurricanes in the past (see: Grace 2021), it feels possible that it does so here as well.

We we will need six things to achieve maximum potential intensity (MPI) here (a real possibility), I'll list it from very likely -> unknown:

1) High OHC (obvious we have this)
2) Wind shear to decrease to > 10kt (very likely)
3) Subsidence/dry air entrainment to be minimal (very likely)
4) Efficient outflow to rapidly advect updrafted air away (likely)
5) A pinhole eye to sustain RI to cat 5 (unknown, only mesoscale models can parameterize this)
6) Like you stated, it needs to stay far enough south of Jamaica to not have inflow disrupted (uncertain)

The NHC is following the consensus models (particularly HCCA) and hedging towards the Google DeepMind/EAIFS ensemble tracks currently (they've done shockingly well this year). Looking at mesoscale models that are following this track currently, HAFS-A again has the most accurate run at 12z:


HAFS-B has its peak at the same time, but more to the north in location:


HMON is similar to HAFS-B


I'm not buying the HWRF, as it's track is far too quick (landfall already tomorrow evening in Jamaica):


Again, I think the HAFS-A has done really well with the structural changes and speed of Melissa, and is supported by the best performing consensus model and the AI ensemble suite. I think RI is almost certain imo and Cat 4/5 is a real possibility depending on that initial structure (i.e., no EWRC and ability for radial winds to refine a pinhole eye structure).

[Hurricane2022]

 https://x.com/MikeFischerWx/status/1982145421108527404

[aspen]

I’m not sold on the contraction to pinhole eye though, that eye looks about average sized. Good news is that probably means a Milton or Wilma-level explosion isn’t as likely, but bad news is a larger core won’t collapse as quickly into an ewrc upon reaching peak. Could still undergo one, but would probably stabilize for a while first. Won’t matter much either way though, it’s hard to bet against a cat5 peak at this point so Jamaica better be taking this seriously

I'm not "downcasting" but I remain a bit doubtful of a Cat 5 peak. Downsloping from Jamaica has interfered with the development of hurricanes in the past (see: Grace 2021), it feels possible that it does so here as well.

We we will need six things to achieve maximum potential intensity (MPI) here (a real possibility), I'll list it from very likely -> unknown:

1) High OHC (obvious we have this)
2) Wind shear to decrease to > 10kt (very likely)
3) Subsidence/dry air entrainment to be minimal (very likely)
4) Efficient outflow to rapidly advect updrafted air away (likely)
5) A pinhole eye to sustain RI to cat 5 (unknown, only mesoscale models can parameterize this)
6) Like you stated, it needs to stay far enough south of Jamaica to not have inflow disrupted (uncertain)

The NHC is following the consensus models (particularly HCCA) and hedging towards the Google DeepMind/EAIFS ensemble tracks currently (they've done shockingly well this year). Looking at mesoscale models that are following this track currently, HAFS-A again has the most accurate run at 12z:
https://i.imgur.com/9dgtsNI.png

HAFS-B has its peak at the same time, but more to the north in location:
https://i.imgur.com/rVLVqBm.png

HMON is similar to HAFS-B
https://i.imgur.com/tdL3qjo.png

I'm not buying the HWRF, as it's track is far too quick (landfall already tomorrow evening in Jamaica):
https://i.imgur.com/RnFgpIR.png

Again, I think the HAFS-A has done really well with the structural changes and speed of Melissa, and is supported by the best performing consensus model and the AI ensemble suite. I think RI is almost certain imo and Cat 4/5 is a real possibility depending on that initial structure (i.e., no EWRC and ability for radial winds to refine a pinhole eye structure).
https://i.imgur.com/KhP5z5D.gif

Something interesting about both HAFS models is that for days they’ve shown Melissa being unable to fully clear out a nice eye, either pinhole or normal-sized. Could be due to structural factors or a tiny bit of shear left inhibiting effective clearing. It may also be an indication that we’ll see a high-end 4 peak, not a Cat 5. Although the difference in impacts between 150 and 160 mph is going to be pretty minimal — an absolute nightmare scenario regardless.

[Pelicane]

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.

[edu2703]

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

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

[Blown Away]

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?

[cycloneye]

Breaking News

Dvorak up to 5.0.

A. 13L (MELISSA)

B. 25/1800Z

C. 16.9N

D. 75.4W

E. THREE/GOES-E

F. T5.0/5.0

G. IR/EIR/VIS/GMI

H. REMARKS...LLCC EMBEDDED IN W RESULTS IN A DT OF 5.0. THE MET IS
4.5 BASED ON A RAPID DEVELOPMENT TREND OVER THE PAST 24 HOURS. THE PT
IS 5.0. THE FT IS BASED ON THE PT DUE TO THE UNCERTAINTY OF THE EXACT
CENTER POSITION.

[sasha_B]

H. REMARKS...LLCC EMBEDDED IN W RESULTS IN A DT OF 5.0. THE MET IS
4.5 BASED ON A RAPID DEVELOPMENT TREND OVER THE PAST 24 HOURS. THE PT
IS 5.0. THE FT IS BASED ON THE PT DUE TO THE UNCERTAINTY OF THE EXACT
CENTER POSITION.

We have a T5.0 fix on OSPO's 18z satellite bulletin.