NATL: MELISSA - Hurricane - Discussion

[Hurrilurker]

Melissa has an absurdly perfect satellite presentation for a sub category 5 storm (at least as of now).

Yeah I'm honestly surprised the pressure isn't lower with that presentation.

[Travorum]

Eyewall diameter is reported as 15nm now

F. CLOSED
G. C15

[InfernoFlameCat]

Eyewall diameter is reported as 15nm now

F. CLOSED
G. C15

Looks like a successful eyewall meld

[cheezyWXguy]

Wow that is a hell of a tower that just fired off in the western eyewall. So much for an asymmetrical cdo.

[ScottNAtlanta]

Eyewall diameter is reported as 15nm now

F. CLOSED
G. C15

Looks like a successful eyewall meld

...and it happened pretty quickly too

[sasha_B]

With the new convection over the apparently weak western eyewall, and the eyewall merge apparently successful, I'm wondering if we'll get to see the satellite presentation improve even further tonight. ADT was giving instantaneous T#s of 7.5-7.7 quite frequently towards the end of Melissa's initial ERI, but I think we'd need to see much colder cloud tops in the CDO for that to happen again.

[Teban54]

Besides the continued mismatch between satellite-based estimates and true intensity, it remains bizarre how Melissa's continued pressure drops aren't translating to wind speed (as of now).

But if we assume that it just completed an eyewall meld, especially given the larger eye and the new, impressive hot tower to the west... Perhaps the wind will catch up very soon?

[Beef Stew]

Have to think that with that newest burst of convection on the western eye wall and the lack of a pronounced double wind maxima, Melissa is almost inevitably due to strengthen at some point and have her windspeeds and MSLP come closer to matching her structure.

[MEANINGLESS_NUMBERS]

I know these waters are warm and deep at this time of year but I wonder if we’ll start to see upwelling before landfall.

[Beef Stew]

Should be getting another center pass soon

[eastcoastFL]

I know these waters are warm and deep at this time of year but I wonder if we’ll start to see upwelling before landfall.

Doubtful. She would have to basically park in one spot for days for upwelling to become an issue for her. The water is that warm.

[Beef Stew]

NE to SW pass coming up any minute now

[Travorum]

931.7mb extrap, down about 1mb from last pass so the rate of deepening is levelling out. Winds aren't particularly different from earlier, 128kt FL winds in the NE.

[Fancy1002]

Does it look like they missed the eye?

[aspen]

This is the most Cat 5-looking non-Cat 5 I’ve ever seen lol. You’d think it’s like 10 mb deeper than it actually is. Really curious as to why it exhibits the classic Cat 5 structural hallmarks despite falling short in actual intensity. This could also have implications for some of the upper-end Cat 4s with speculated Cat 5 status.

[Teban54]

This is the most Cat 5-looking non-Cat 5 I’ve ever seen lol. You’d think it’s like 10 mb deeper than it actually is. Really curious as to why it exhibits the classic Cat 5 structural hallmarks despite falling short in actual intensity. This could also have implications for some of the upper-end Cat 4s with speculated Cat 5 status.

It's possible that Melissa was just an anomaly. But if we think there's a systematic pattern of "Dvorak but not actual Cat 5s" (for which there's little concrete evidence), then I'd say it affects EPAC even more than the Atlantic. Most borderline Cat 4/5s in the Atlantic had recon coverage at the peak, with Lorenzo and Humberto among the few exceptions that I can think of (and arguably Sam which already started collapsing when recon got there).

[Hypercane_Kyle]

I remember when we all thought Eta was sub-900 nuclear Category 5 and it was actually like in the 930s. This reminds me of that a bit.

[Ubuntwo]

This is the most Cat 5-looking non-Cat 5 I’ve ever seen lol. You’d think it’s like 10 mb deeper than it actually is. Really curious as to why it exhibits the classic Cat 5 structural hallmarks despite falling short in actual intensity. This could also have implications for some of the upper-end Cat 4s with speculated Cat 5 status.

It makes sense here - this is the Caribbean in late season. Dvorak is overreliant on convective depth, so a high tropopause can cause overestimates in intensity. Eta's a great extreme example. This is the same reason open Atlantic 130kt+ systems (Sam, Fiona, Jose, Kirk etc) struggle so hard to hit T7.0. I think we've come to recognize here that eye warmth, roundness, and stability plus CDO smoothness are better indicators of extreme intensity. Melissa did briefly have a near-perfect eye, but its CDO has yet to transition past the bursting phase, at least consistently.

[michelinj]

This is the most Cat 5-looking non-Cat 5 I’ve ever seen lol. You’d think it’s like 10 mb deeper than it actually is. Really curious as to why it exhibits the classic Cat 5 structural hallmarks despite falling short in actual intensity. This could also have implications for some of the upper-end Cat 4s with speculated Cat 5 status.

My thinking is that this is similar to what we saw with Eta in 2020 which had super-cold cloud tops and incredible satellite presentation and then recon arrived to find a low-mid level cat4. These late season storms can be misleading due to the extra cold cloud tops. I suspect we’re seeing the same again.

Just because we’ve had lots of cat5s lately doesn’t mean that to get that strong a storm doesn’t need to be pretty much PERFECT, and I wouldn’t say Melissa has looked like that yet. Cold CDO? Yes. Warm eye? Yes. But we had something going on in the west eye wall earlier, and even now the eye is slightly misshapen as if some eyewall process is still ongoing. Not saying she won’t get there though…

[BobHarlem]

The radar loop makes it look like it's wobbling wsw