NATL: MELISSA - Aftermath - Discussion

[WaveBreaking]

Some images I grabbed from the GOES-19 satellite using NOAA CLASS data and McIDAS-V during/near its peak intensity

[cycloneye]

Yes!! On monday, Josh will release preliminary data. Can't wait.

 https://x.com/iCyclone/status/1989825156639035639

[cycloneye]

And here it is, the Josh report of his chase of Melissa in Jamaica.

 https://x.com/iCyclone/status/1990510838663336169

@iCyclone
And here's my report on #Hurricane #MELISSA in #Jamaica. Please note this is purely meteorological & it's quite technical—so casual readers focused on the human impact won't find it interesting. Meteorologists & weather nerds, on the other hand, will find this rare look deep inside the core of one of the strongest known hurricane landfalls fascinating. Main points:

* My location was well inside the RMW (radius of maximum winds) & got totally raked by the eyewall’s inner right-front quadrant.

* The SE edge of the eye apparently grazed my location, temporarily bringing reduced wind speeds, improved visibility, and a marked shift in wind direction.

* My minimum pressure was 926.0 mb. While this might seem high, the report discusses how it actually makes sense, given recon data & the fact that I was probably a few miles from the absolute center.

* MELISSA's winds were absolutely ferocious—the most intense I've witnessed in 84 hurricanes. And the resultant damage was spectacular. This was a truly rare specimen.

This is a preliminary version of this report which I rushed to completion because of time-sensitive requests for the data. In the next couple of weeks, I'll be releasing an expanded version with plentiful damage pics.

My next focus: the video! I am hoping to get that out in the next 1-2 weeks.


Link to whole report= [b] https://static1.squarespace.com/static/ ... SA2025.pdf

[/b]

[CrazyC83]

Based on all that data, I wonder if the pressure actually dropped before landfall, despite the slightly warmer cloud tops - perhaps the push of momentum? The Recon in the same spot measured about 935 mb and he measured 926 mb, although that may be too inconclusive.

Another scenario is that the RMW was starting to expand due to the famous eyewall melds (one was likely ongoing at its peak), so it may have raised the central pressure but started to spread it out. I would personally lean towards that scenario and trust the satellite imagery. After all, Melissa's 892 mb pressure was the lowest on record for an Atlantic storm with an eye of 15 nmi or larger (previous record was Rita) - all the others in extreme intensity territory had pinholes. That makes me think that 897 mb (+/- 5 mb) was the most likely landfall pressure. That would also support the landfall intensity being 5 kt (maybe 10 kt) lower than the peak.

It is worth noting that he probably got the eyewall about 20-30 minutes before the actual landfall, since that was a bit further up the coast, likely at 1715Z between New Hope and Auchindown.

I also calculated using the Schloemer equation, starting with my 897 mb assessment, and it comes out at 926 using the RMW of 8 nm, the distance of 6 nm and the OCI of 1008 mb.

[CronkPSU]

https://www.cbsnews.com/news/hurricane-melissa-record-breaking-winds-dropsonde-data-confirms/

"NOAA researchers contacted the NSF NCAR to confirm that it was the highest wind speed ever recorded by a dropsonde.

"NOAA looped us in when they saw the high wind speed and asked, 'Are these numbers any good?'" said Holger Vömel, an NSF NCAR senior scientist who works with the organization's Dropsonde Program.

To verify the data, Vömel and other researchers reviewed the numbers with a quality control software. They also confirmed that the reported 252 mile wind gust would have been physically possible, and that it tracked with the hurricane's behavior, as well as previous storm patterns. The review confirmed that the wind gust measurement was accurate.

The previous fastest wind gust recorded by a dropsonde was in 2010, when Typhoon Megi unleashed a 248 mile per hour blast while over the western Pacific Ocean. During Hurricane Katrina, researchers thought they had recorded an even stronger gust, but the data had substantial issues, the NSF NCAR said. "

[mrbagyo]

https://www.cbsnews.com/news/hurricane-melissa-record-breaking-winds-dropsonde-data-confirms/

"NOAA researchers contacted the NSF NCAR to confirm that it was the highest wind speed ever recorded by a dropsonde.

"NOAA looped us in when they saw the high wind speed and asked, 'Are these numbers any good?'" said Holger Vömel, an NSF NCAR senior scientist who works with the organization's Dropsonde Program.

To verify the data, Vömel and other researchers reviewed the numbers with a quality control software. They also confirmed that the reported 252 mile wind gust would have been physically possible, and that it tracked with the hurricane's behavior, as well as previous storm patterns. The review confirmed that the wind gust measurement was accurate.

The previous fastest wind gust recorded by a dropsonde was in 2010, when Typhoon Megi unleashed a 248 mile per hour blast while over the western Pacific Ocean. During Hurricane Katrina, researchers thought they had recorded an even stronger gust, but the data had substantial issues, the NSF NCAR said. "

Does that "gust" meet WMO's definition of wind gust (3 second average wind speed) or is it just instantaneous wind speed?

[Team Ghost]

Reports indicate that drinking water has been contaminated in the aftermath of Hurricane Melissa, leading to an outbreak of leptospirosis.

https://www.nytimes.com/2025/11/21/us/j ... lissa.html

[WaveBreaking]

Some images I grabbed from the GOES-19 satellite using NOAA CLASS data and McIDAS-V during/near its peak intensity

https://i.imgur.com/7Q1Gsof.png

https://i.imgur.com/XvQ5C6s.png

Got the color table wrong on the IR one so the values were blown out of proportion. Here's the corrected image.

[cycloneye]

Josh Morgerman analisis of the landfall.



 https://x.com/iCyclone/status/1992727637635014892

[cycloneye]

It will take years to recover completly and he is going back.

 https://x.com/iCyclone/status/1995622350059176250

[cycloneye]

Josh final report. The video is comming very soon.

 https://x.com/iCyclone/status/1996176765753147735



Hyperlink to final report

[CrazyC83]

I took a second look at the BT based on the data. A few changes in timing, track and intensity are warranted, largely based on Josh's data.

AL132025, MELISSA, xx,
20251020, 1200, , LO, 13.5N, 66.5W, 30, 1008,
20251020, 1800, , LO, 13.7N, 67.7W, 35, 1006,
20251021, 0000, , LO, 13.9N, 68.9W, 35, 1005,
20251021, 0600, , LO, 14.1N, 70.1W, 40, 1004,
20251021, 1200, , LO, 14.1N, 71.3W, 40, 1003,
20251021, 1800, , LO, 14.1N, 72.5W, 40, 1002,
20251022, 0000, , TS, 14.1N, 73.2W, 45, 1002,
20251022, 0600, , TS, 14.2N, 73.4W, 45, 1001,
20251022, 1200, , TS, 14.3N, 73.6W, 45, 1000,
20251022, 1800, , TS, 14.4N, 73.9W, 40, 1002,
20251023, 0000, , TS, 14.6N, 74.3W, 40, 1004,
20251023, 0600, , TS, 14.8N, 74.6W, 35, 1005,
20251023, 1200, , TS, 15.2N, 75.0W, 35, 1005,
20251023, 1800, , TS, 15.5N, 75.3W, 40, 1002,
20251024, 0000, , TS, 15.7N, 75.6W, 40, 1001,
20251024, 0600, , TS, 16.0N, 75.3W, 40, 1001,
20251024, 1200, , TS, 15.8N, 74.9W, 45, 1000,
20251024, 1800, , TS, 15.8N, 74.5W, 50, 996,
20251025, 0000, , TS, 16.1N, 74.7W, 55, 993,
20251025, 0600, , TS, 16.3N, 74.9W, 60, 986,
20251025, 1200, , HU, 16.4N, 75.1W, 65, 983,
20251025, 1800, , HU, 16.5N, 75.3W, 70, 977,
20251026, 0000, , HU, 16.4N, 75.7W, 85, 970,
20251026, 0600, , HU, 16.3N, 76.0W, 100, 957,
20251026, 1200, , HU, 16.4N, 76.4W, 110, 952,
20251026, 1800, , HU, 16.4N, 76.9W, 120, 944,
20251027, 0000, , HU, 16.4N, 77.3W, 130, 932,
20251027, 0600, , HU, 16.3N, 77.7W, 135, 922,
20251027, 1200, , HU, 16.4N, 78.0W, 145, 913,
20251027, 1800, , HU, 16.4N, 78.3W, 155, 906,
20251028, 0000, , HU, 16.5N, 78.6W, 155, 905,
20251028, 0600, , HU, 16.9N, 78.4W, 160, 899,
20251028, 1200, , HU, 17.5N, 78.2W, 170, 890,
20251028, 1730, L, HU, 18.1N, 78.0W, 155, 901,
20251028, 1800, , HU, 18.2N, 77.9W, 140, 908,
20251029, 2130, R, HU, 18.6N, 77.4W, 95, 955,
20251029, 0000, , HU, 18.9N, 77.2W, 100, 953,
20251029, 0600, , HU, 19.8N, 76.3W, 105, 951,
20251029, 0715, L, HU, 20.0N, 76.1W, 105, 950,
20251029, 1200, , HU, 20.9N, 75.8W, 75, 972,
20251029, 1800, , HU, 22.1N, 75.3W, 80, 974,
20251029, 2130, L, HU, 22.5N, 75.0W, 85, 971,
20251030, 0000, , HU, 23.5N, 74.8W, 90, 970,
20251030, 0215, L, HU, 24.0N, 74.5W, 90, 969,
20251030, 0600, , HU, 24.9N, 73.8W, 95, 966,
20251030, 1200, , HU, 26.6N, 72.8W, 100, 964,
20251030, 1800, , HU, 28.8N, 71.0W, 90, 968,
20251031, 0000, , HU, 31.3N, 68.9W, 80, 970,
20251031, 0600, , HU, 34.4N, 65.5W, 75, 972,
20251031, 1200, , HU, 37.5N, 62.1W, 70, 972,
20251031, 1800, , EX, 40.6N, 58.6W, 70, 972,
20151101, 0000, , EX, 44.1N, 55.2W, 65, 973,
20151101, 0600, , EX, 47.4N, 49.0W, 60, 975,
20151101, 1200, , EX, 49.8N, 44.5W, 55, 979,
20151101, 1800, , EX, 51.0N, 42.0W, 50, 983,

The first big change is in the period at peak intensity and near landfall in Jamaica. The landfall time is delayed 30 minutes to 1730Z based on a blend of radar and satellite analysis (leaning towards radar but understanding there was a bit of angle differences) and the timing of the calm winds and pressure minima, which support a later landfall time.

Additionally, the thought that Melissa peaked before Recon arrived is validated by the readings and trends from the limited Recon data. As a result, a new minimum pressure estimate of 890 mb is analyzed at 1200Z (which fits in at synoptic time). Based on weakening up to landfall and timing differences, the landfall pressure is adjusted upwards to 901 mb, and the intensity revised downward slightly to 155 kt.

Departure time from Jamaica is also moved up to 2130Z, although the intensity at that time - 95 kt - is unchanged. (That is considerably lower than the NHC operational 115-120 kt then - this assessment assumes slight strengthening before Cuba where the 105 kt intensity appears accurate, as opposed to weakening).

An intensity of 100 kt is also added at 1200Z October 30 near the Bahamas, when readings seemed to suggest T5.5 and Recon was showing a final peak before rapid weakening.

[ljmac75]

Josh has really been busy, looks like he met with an NHC guy. (Probably to lobby for Melissa being upgraded to 190 mph. At a non-synoptic point labelled "eyewall hitting Crawford." (This is a joke, he does good work)

https://x.com/iCyclone/status/1994602362087063644