#Melissa has impressive outflow and upper divergence beginning as it interacts with the oncoming upper trough. This may allow for another unfortunate burst of intensification (barring an EWRC) as it approaches Jamaica

Apologies for the https://t.co/zedO4ptg7M outage. Unprecedented traffic puts my server under a lot of pressure! It should be back now, and hopefully it will stay that way

And there we have it. #Melissa's WV eye temperature has broken -5°C, making it warmer than any other eye observed through geostationary water vapor imagery. Takes an upper echelon warm core for this

Why guess when you can know?

Also crazy subsidence inversion in #Melissa's eye. At 907mb, you get weird stuff like 30C at 775mb!

#Melissa has had some interesting dropsonde observations. Dropsondes tend to be a rather conservative way of measuring maximum wind, but this one supports as high as 155kt. Bottom-heavy profile may be making flight level winds seem too weak

Also worth noting #Melissa's very warm eye on water vapor imagery. -7.5°C is even warmer than Erin from this August and reflects extreme subsidence (drying+warming) in the eye. About as strong as warm cores get in the Atlantic basin

#Melissa has continued strengthening overnight, to a pressure around 913-914mb, with winds having risen to about 145-150kt based on obs from this morning's recon. Surprisingly no sign of an ERC yet. Can only hope there is some weakening on the way soon, awful situation for

I have been seeing a significant amount of chatter on this “MERC” or merger eyewall replacement cycle and how one is thought to have occurred in Melissa. It’s my understanding this was first documented in Hurricane Irma in this paper I authored: https://t.co/07gLcNhWI8 🧵

As recon leaves, #Melissa's satellite presentation once again improves. Lots of new bursting around the eyewall and another cooling of the CDO. Look at those gravity waves going outwards! Suggests a strengthening storm but satellite trends haven't totally agreed with recon obs

#Melissa's satellite presentation has become quite impressive this afternoon, with a more symmetric, cold CDO, and a warming, drying eye. Suggests continued strengthening is occurring. Will be interesting to see just how much it's deepening from recon soon

#Melissa is well into Category 4 status this morning. After a pause in RI, recon is reporting that the eye has contracted significantly to pinhole size (8nm), and intensification has resumed. Jamaica will soon get into the NE quadrant, with torrential rain and embedded supercells

So far it seems despite the eye clearing out #Melissa's intensification hasn't been explosive as thought. Could be some of the shear that has still not gone away is subtly disrupting it for now. Still, landfall is not expected for another couple days so it is not time to let your

Recon is finding #Melissa notably stronger, at about 85kt with pressure having dropped all the way to 971mb. The wind field is much more coherent and symmetric, and there are double hot towers trying to surround the eye. Could see some impressive intensification rates from recon

#Melissa has had several vortical hot towers appear wrap around its eyewall, with another active right now. Likely heralds the beginning of RI when these wrap more. Will certainly be interesting to see what recon finds. Seems tonight will be the long-predicted quick strengthening

A pair of recent microwave passes over #Melissa show a nice cyan ring on the 37 GHz; a clear sign that a period of rapid intensification is likely on the way.

#Melissa looks like it has managed to stack this morning and looks fairly healthy on satellite. Wind field is a little interesting though. Was west weighted earlier and now east weighted. Doesn't look like a RI phase right now but the structure is no longer in the way like

While #Melissa has begun to strengthen and has a well-defined LLC, its MLC is still quite far off to the ESE. Sign of the shear that hasn't quite let up. Will not see more rapid intensification until the tilt reduces

#Melissa may finally be getting itself together this afternoon. It has begun to produce higher winds and deepen, and the center is well embedded within the convection. Shear is decreasing so this may herald the anticipated strengthening. Once again worth keeping a close eye on in

Massive cave by the GFS to other guidance for the track of #Melissa. Honestly that's pretty remarkable to see that kind of error/adjustment for a 3 day forecast - don't see that too often with modern NWP.

Looking at this morning's recon, #Melissa looks to have moved or reformed further east. A little fly in the ointment is the dropsondes suggest a surface center quite a bit further south. Could still be quite tilted. Melissa has a lot of work to do when shear comes down