NATL: MELISSA - Aftermath - Discussion: Josh Morgerman video of Melissa is up

[LarryWx]

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.

It isn’t just upwelling that cools the waters at or near where a hurricane crosses: it also cools due to the conservation of energy (potential energy from warm water transitions to kinetic (wind) energy of the storm/heat engine), cooling from raindrops (I assume this factor is relatively minor), and cooling from cloudcover blocking the sun:

Hurricanes cool the ocean by acting like "heat engines" that transfer heat from the ocean surface to the atmosphere through evaporation.

Cooling is also caused by upwelling of cold water from below due to the suction effect of the low-pressure center of the storm.

Additional cooling may come from cold water from raindrops that remain on the ocean surface for a time.

Cloud cover may also play a role in cooling the ocean by shielding the ocean surface from direct sunlight before and slightly after the storm passage.

All these effects can combine to produce a dramatic drop in sea surface temperature over a large area in just a few days.

https://earthobservatory.nasa.gov/image ... he%20storm

[cheezyWXguy]

Given the slow rate of intensification at the moment, I’m not sure that the ewrc/meld has fully completed just yet. Cdo and eye are still wobbling despite the notably cooler cloud tops and clear eye.i would imagine that completion of the cycle in such good conditions and such an optimal structure would result in at least a brief burst of faster intensification but we haven’t seen that quite yet. May still need more time to sort the last the process out.

[hipshot]

There's definitely a notable wobble to the SW, the latest VDM fixed Melissa at 16.3N when the official track never drops below 16.4N. Obviously its very difficult to predict future trochoidal wobbles but this SW motion is significant and persistent enough that you have to wonder if it will have long term impacts on the future track.

NHC specifically said in one of their discussions that a SW movement was probable, but opted to show a due west movement because the SW movement wouldnt likely be sustained.

I'm still concerned about that trough catching Melissa and pulling it NE. If it doesn't, we have a huge problem!

[Tekken_Guy]

There's definitely a notable wobble to the SW, the latest VDM fixed Melissa at 16.3N when the official track never drops below 16.4N. Obviously its very difficult to predict future trochoidal wobbles but this SW motion is significant and persistent enough that you have to wonder if it will have long term impacts on the future track.

NHC specifically said in one of their discussions that a SW movement was probable, but opted to show a due west movement because the SW movement wouldnt likely be sustained.

I'm still concerned about that trough catching Melissa and pulling it NE. If it doesn't, we have a huge problem!

What exactly are you referring to?

[BobHarlem]

There's definitely a notable wobble to the SW, the latest VDM fixed Melissa at 16.3N when the official track never drops below 16.4N. Obviously its very difficult to predict future trochoidal wobbles but this SW motion is significant and persistent enough that you have to wonder if it will have long term impacts on the future track.

NHC specifically said in one of their discussions that a SW movement was probable, but opted to show a due west movement because the SW movement wouldnt likely be sustained.

The halfs models showed the sw dip (to around 16.2N -- The last recon fix was 16.3N), and they show it gaining latitude in about 3-4 hours from now, but not really going north until later tomorrow (landfall Tuesday morning). (halfs a also shows 905-910mb landfall) So that's what to look out for.

[hipshot]

NHC specifically said in one of their discussions that a SW movement was probable, but opted to show a due west movement because the SW movement wouldnt likely be sustained.

I'm still concerned about that trough catching Melissa and pulling it NE. If it doesn't, we have a huge problem!

What exactly are you referring to?

As I understand it, there is a trough coming through to the north that will pull Melissa north, up through Jamaica, eastern Cuba and
then the Bahamas and that should happen in about 36 hours our so from now. If Melissa continues south and then to the west, it might
not be able to get the pull they are all talking about. I'm just a weather nerd but I get concerned when we have this kind of storm
moving towards the gulf.

[Tekken_Guy]

I'm still concerned about that trough catching Melissa and pulling it NE. If it doesn't, we have a huge problem!

What exactly are you referring to?

As I understand it, there is a trough coming through to the north that will pull Melissa north, up through Jamaica, eastern Cuba and
then the Bahamas and that should happen in about 36 hours our so from now. If Melissa continues south and then to the west, it might
not be able to get the pull they are all talking about. I'm just a weather nerd but I get concerned when we have this kind of storm
moving towards the gulf.

I don’t believe that’s a trough. Just the typical late-season recurve.

[hipshot]

What exactly are you referring to?

As I understand it, there is a trough coming through to the north that will pull Melissa north, up through Jamaica, eastern Cuba and
then the Bahamas and that should happen in about 36 hours our so from now. If Melissa continues south and then to the west, it might
not be able to get the pull they are all talking about. I'm just a weather nerd but I get concerned when we have this kind of storm
moving towards the gulf.

I don’t believe that’s a trough. Just the typical late-season recurve.

I'm not aware of anything called a typical late-season recurve. There is always some weather pattern that causes those to happen.

[Hurricane2022]

I still can't believe this is not even a low-end C5...

[Beef Stew]

SE to NW pass coming up momentarily. Let’s see if she’s deepened any.

[Travorum]

SE to NW pass coming up momentarily. Let’s see if she’s deepened any.

Not sure if they hit the exact center since FL winds never dropped below 39kts, but minimum pressure was 934mb. Peak FL winds in both N and S were 124kts.

[Hurricane2022]

Looks like they missed the eye a bit, but the FL winds are the same. Melissa doing another pause for lunch.

[michelinj]

Based off that latest pass, the hints of a double wind max seem to have all but gone (slight one in the SE perhaps) so whatever eyewall process happened should be done or almost done. Will be interesting to see how satellite changes. I have to say she has a long way to go for cat 5 wind speed wise…

Devastating for Jamaica regardless of course

[AtlanticWind]

I'm still concerned about that trough catching Melissa and pulling it NE. If it doesn't, we have a huge problem!

What exactly are you referring to?

As I understand it, there is a trough coming through to the north that will pull Melissa north, up through Jamaica, eastern Cuba and
then the Bahamas and that should happen in about 36 hours our so from now. If Melissa continues south and then to the west, it might
not be able to get the pull they are all talking about. I'm just a weather nerd but I get concerned when we have this kind of storm
moving towards the gulf.

There is really no concern that a slight dip SW will make any difference in
The turn to the N and NE that will occur tomorrow

[IsabelaWeather]

There's definitely a notable wobble to the SW, the latest VDM fixed Melissa at 16.3N when the official track never drops below 16.4N. Obviously its very difficult to predict future trochoidal wobbles but this SW motion is significant and persistent enough that you have to wonder if it will have long term impacts on the future track.

NHC specifically said in one of their discussions that a SW movement was probable, but opted to show a due west movement because the SW movement wouldnt likely be sustained.

I'm still concerned about that trough catching Melissa and pulling it NE. If it doesn't, we have a huge problem!

Im not sure what youre worried about, there is pretty much zero threat to the CONUS. Even if it somehow hit, it would only be extreme south florida, but again, that is almost assured to not happen. It also wouldnt be the storm we have now, its almost november, the CONUS threat is pretty much closed. And any storm would be sheared like crazy.

[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.

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.

CDO temperature isn’t the main thing sticking out to me about Melissa, though. For a few hours it had among the most symmetrical and robust CDOs I’ve seen in the Atlantic, comparable to or even a little better than Sam. Even if you were to try and correct the cloud temperatures to something from outside the Caribbean, you’d probably still have a W ring on Dvorak (again, like Sam). ~20C eye temps also put it among the Atlantic’s best in recent years.

I agree with you about the CDO bursting/inconsistency, though I’m curious as to why it’s remained even as the system matures and deepens. It may also indicate that some of the Cat 4 EPac systems which have been suspected to be 130-140 kt — Douglas, Darby, Dora, Gilma, etc — may have also been a tad weaker than our typical assessments of eye temperature and CDO smoothness have suggested. Or maybe this is just a weird outlier lol.

[Teban54]

Is there something with Melissa's eye that makes the NOAA aircraft keep missing it, or is it just a streak of bad luck? This time, extrapolated pressure bottomed out at 934.0 mb with 39 kt FL winds. I don't even know if they did an eye drop at all; current data looks like they have skipped it.

Peak FL winds of 124 kt in both SE and NW quads remain unimpressive relative to the appearance, though not atypical of storms that just went through an EWRC (or similar).

Regardless, Melissa still found a way to look more impressive on IR. Whether that translates to intensification is anyone's guess.

[Hurricane Mike]

What a monster. Looks like it might do an ERC in the next 12 hrs or so. Not good, because then the wind field will expand further.

[ElectricStorm]

Eye drop 938/28, supports 935mb so rose slightly from last pass

[ScottNAtlanta]

Eye drop 938/28, supports 935mb so rose slightly from last pass

That would translate down to 935, so more or less steady. The other 2 passes were 937/936 but they missed a little both times