NATL: MELISSA - Tropical Storm - Discussion

[zzzh]

New forecast calls for a 125kt peak.

[al78]

New forecast calls for a 125kt peak.

I suspect there is a lot of uncertainty at days 4 and 5 because it depends on how close the storm gets to Jamaica and thus how much land interaction will affect it. Jamaica is quite mountainous so if the core came ashore there I would expect it to get somewhat disrupted and weakened, especially with the forecast slow movement.

[CrazyC83]

New forecast calls for a 125kt peak.

I suspect there is a lot of uncertainty at days 4 and 5 because it depends on how close the storm gets to Jamaica and thus how much land interaction will affect it. Jamaica is quite mountainous so if the core came ashore there I would expect it to get somewhat disrupted and weakened, especially with the forecast slow movement.

I know Sandy didn't weaken at all over Jamaica, but it was moving at a decent clip.

[CrazyC83]

At first I thought a Jamaica landfall could prevent Melissa from becoming "too strong" (aka a cat 1 or less) before it inevitably strikes a populated area. But with that latest model cycle showing a cat 4/5 Jamaica landfall, I fear we're looking at a lose/lose and it'll be catastrophic no matter what happens. Maybe the best case scenario is a bombing out phase south of Jamaica and missing the island followed by EWRCs weakening Melissa.

The best-case scenario for Melissa's impacts seems to be a Delta-esque collapse, from a pinhole Cat 4 to a weakening Cat 2 at its Yucatan landfall (that didn't even warrant retirement).

Absent that... Yeah, Melissa will most likely wreck havoc on someone no matter what, even if the target is unclear.

But if it does a loop around Jamaica staying south and west, it likely hits Cuba as a monster hurricane. It would be far enough away from Jamaica in that case that land interaction would not be a factor - and those runs send the intensity to the stratosphere (a lot of sub-900 scenarios there).

[MGC]

Lets hope Melissa tracks directly over Jamaica and don't achieve Cat-4-5 intensity......MGC

[blp]

I am seeing her out pacing the convection. I see it at around 16N 76.4W. Maybe it is a vort.

https://www.tropicaltidbits.com/sat/satlooper.php?region=13L&product=vis

[chaser1]

New forecast calls for a 125kt peak.

I suspect there is a lot of uncertainty at days 4 and 5 because it depends on how close the storm gets to Jamaica and thus how much land interaction will affect it. Jamaica is quite mountainous so if the core came ashore there I would expect it to get somewhat disrupted and weakened, especially with the forecast slow movement.

For sure! In fact, I have a theory that Melissa will actually track between WSW and SW by around day 3. Looking at both EURO & GFS 500 MB vorticity forecasts for that period, they both imply a seemingly distinct steering flow from the northeast as a result of the W. Gulf ridging that soon expands eastward through S. Florida and the W Bahamas. In fact, the forecast ridging was discussed in the Discussion as well as by Levi; both instances suggested that a west motion should then ensue.

My two questions are:
- Given the 500mb flow depicted at that time by both Global models, why was there no suggestion or thought that a South of west track might occur?
- My biggest question however is given the forecast influence of the ridge building north of Mellisa, was the westward track and speed over the 2-3 day period so negligible (seemingly near or under 5 mph)?

(Appologies for the model related questions in this thread but was in direct response to the prior post)

[Hurricane Mike]

5:30pm Video Update on Melissa
https://www.youtube.com/watch?v=IBNUWOYoLIw

[InfernoFlameCat]

Lets hope Melissa tracks directly over Jamaica and don't achieve Cat-4-5 intensity......MGC

I would hope it doesn’t do that. I hope it somehow threads the needle and misses land

[sasha_B]

I don't think the feature running away is the LLC.

The NOAA recon flight currently en route will be able to confirm the location of the LLC one way or another. The 21z forecast of gradual intensification (as opposed to a steady state) in the short-term, and RI beginning around 18z tomorrow, suggests that the process of vertical alignment may already be ongoing, so the storm remaining severely tilted like it has been for another 24h would be a significant deviation from the NHC's expectations.

[ljmac75]

Lets hope Melissa tracks directly over Jamaica and don't achieve Cat-4-5 intensity......MGC

I would hope it doesn’t do that. I hope it somehow threads the needle and misses land

The weather nerd in me wants to see an ultra-strong cat 5. The humanitarian in me wants to see an ultra strong cat 5 that stays away from land. The realist in me expects neither.

[zzzh]

I don't think the feature running away is the LLC.

Recon confirms

[cycloneye]

I don't think the feature running away is the LLC.

https://i.imgur.com/ajMBjSe.png
Recon confirms

That is a MLC.

[ljmac75]

Which number center is this? 3rd? 4th?

[cycloneye]

From the 8 PM advisory:

...NOAA HURRICANE HUNTERS REPORT THAT THE CENTER OF MELISSA HAS
REFORMED A LITTLE TO THE NORTH...

[zzzh]

I don't think the feature running away is the LLC.

https://i.imgur.com/ajMBjSe.png
Recon confirms

That is a MLC.

How is 850mb mid level?

[zzzh]

Another dropsonde. The center is definitely elongated from SE to NW.

[Nimbus]

Levi did a good job with a nuance of the ensemble evolution through the first 60 hours for the GFS VS Euro.
Melissa is moving so slow that precipitation especially for Jamaica will be measured in feet with the ridge capture scenario.
Beyond 100 hours there isn't really a safe escape route north so this is going to be bad.

https://www.tropicaltidbits.com/

[chaser1]

Levi did a good job with a nuance of the ensemble evolution through the first 60 hours for the GFS VS Euro.
Melissa is moving so slow that precipitation especially for Jamaica will be measured in feet with the ridge capture scenario.
Beyond 100 hours there isn't really a safe escape route north so this is going to be bad.

https://www.tropicaltidbits.com/

Agreed, Levi broke down things very well but he did not really discuss what extent of ridging (how far west) Melissa might track westward once the ridge built just north & northwest of it.

[NDG]

Melissa is still so tilted that the recon dropped to 5k feet to fix its LLC before going back up to its usual 10k cruising altitude, so many MLC vorticities to the east of the LLC.
The Euro is still persistent that it will be affected with westerly shear for the next 24-36 hrs, once the mid level ridge builds to its north the LLC and MLC will start getting aligned.