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Hurricane Melissa

Working theory - there have been EWRCs, it's just so moist at all levels that they are basically mergers that weren't as obvious because they are less disruptive.

Nerdy AI assisted theorizing:
Rainband downdrafts & θe dilution: Outer rainband convection often seeds the secondary ring but also drives evaporatively cooled downdrafts that inject low-θe (drier, cooler) air into the moat/inner core. In a moist envelope (high 700–500 hPa RH), those downdrafts are weaker (less evaporative cooling), so there’s less dry air intrusion to erode the inner eyewall. The inner ring stays healthier, so “replacement” becomes “merger.”

PV mixing vs. collapse: With less θe dilution, vortex-Rossby-wave activity and axisymmetric inflow can radially mix PV between the two rings. The result is a reconstitution into a single, still-strong ring rather than the inner ring starving to death.

Energy supply not pinched: In very high OHC/SST setups, surface enthalpy flux can feed both rings for longer. That reduces the classic energy-competition phase that forces the inner ring to decay, again favoring a gentle merge.

Less moat subsidence drying: The diabatic heating in the budding outer ring normally induces subsidence/drying in the moat. If the environment starts moist, the moat never gets as stable/dry, keeping convective “bridges” alive that physically knit the rings together.

What moisture probably doesn’t do:
It likely doesn’t prevent SEF/EWRC outright - those are largely internal dynamical processes tied to angular-momentum fluxes and the radial wind profile. But moisture can modulate the character of the cycle: shallow or near-zero intensity dip, shorter duration, and a higher chance of the “merge” phenotype.

Straight up though - to test this theory will require a lot more data than just Melissa.
 
Truly remarkable that we can make comparisons to Pacific Super Typhoons and it's not even hyperbolic here. Not sure what kinds of records she'll break in the end, but she's at the very top of my list on Atlantic storms. Also, she is making a northward jog, as @slenker mentioned.
goes19_ir_13L_202510272345.gif
 
Final overnight prediction: this doesn't go sub-900. Whether it's recon missing the peak or the actual intensity not matching with the appearance, what I've been seeing from this storm so far makes me think we'll have a peak pressure of perhaps 902 as on the previous dropsonde.

Now I must sleep.
 
Since we are confessing things out of the blue, I'm a word nerd. Hurricane words combine two things I love.

"Surface enthalpy flux". Sounds inappropriate - is about hurricanes. One of my favorite nerdy hurricane phrases. Not nearly as complicated as it sounds - it's the total energy transferred from the ocean surface to the atmosphere in the form of both sensible heat (warm air exchange) and latent heat (moisture evaporation). It’s the hurricane’s fuel delivery system.
 
Lake Martin EF4 said:
Final overnight prediction: this doesn't go sub-900. Whether it's recon missing the peak or the actual intensity not matching with the appearance, what I've been seeing from this storm so far makes me think we'll have a peak pressure of perhaps 902 as on the previous dropsonde.

Now I must sleep.
Click to expand...
I agree just because we probably only have two more drops. I doubt the first pass in the morning (scheduled to be about 630 am EDT) will get there in time.
 
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