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

[Nimbus]

The level of intensity that Jamaica took from Melissa is surprising. Are "perfect" storms like Melissa, particularly vulnerable to severe attenuation , in comparison to your normal run of the mill big blob Cat III or the like?

Not really, most of the Montego Bay habitation is located on the west side of 1000 foot hills which shields them from high wind observations till they get back out over water. Melissa looks to be coming back some tonight unless the dry air has arrived?

[ljmac75]

It looks to me like the NHC went with the standard inland decay rate for Melissa's weakening after landfall (presumably because they have nothing else to go by, this is the first hurricane to take a northward track over the western side of Jamaica in almost 100 years). Works pretty well for the gulf coast, not so well for a rather rugged island.

[CrazyC83]

It looks to me like the NHC went with the standard inland decay rate for Melissa's weakening after landfall (presumably because they have nothing else to go by, this is the first hurricane to take a northward track over the western side of Jamaica in almost 100 years). Works pretty well for the gulf coast, not so well for a rather rugged island.

Maria, which was moving faster and had a larger RMW, dropped from 135 kt to 95 kt in about 4 hours over Puerto Rico. I was thinking that could be a comparison.

[Beef Stew]

The level of intensity that Jamaica took from Melissa is surprising. Are "perfect" storms like Melissa, particularly vulnerable to severe attenuation , in comparison to your normal run of the mill big blob Cat III or the like?

Generally, yes. The way I like to think of it is this: which is going to be an easier repair job if you crash it- a 2005 Ford F150 or a brand new Ferrari?

A category 5, especially an upper echelon one like Melissa, is a highly refined, highly sensitive heat engine. It performs at the highest standards as a cyclone can, but any little perturbation can quickly spiral and cause a huge disruption (think Delta in 2020) that can be difficult to recover from. A run of the mill cat 3, as you mentioned- or certainly a lesser storm- might be more resilient to having its circulation disrupted by land, shear, etc because it doesn’t have to be as efficient, as perfect by nature- that’s why it’s not a C4 or 5.

If circulation can persist, a former category 5 can reintensify at a good pace if conditions are favorable, but after traversing significant elevation it’s never a seamless process.

[Nimbus]

The level of intensity that Jamaica took from Melissa is surprising. Are "perfect" storms like Melissa, particularly vulnerable to severe attenuation , in comparison to your normal run of the mill big blob Cat III or the like?

In spite of its strength and intensity landfall, I think the Melissa's relatively small RMW made it more easily disrupted by the high terrain of Jamaica (even though the higher peaks are on the central-east part of the island).

The drier air earlier in Melissas development kept the RMW in check and there were no major EWRcs to increase that which is the thing that is a little strange. Small core system going over rough terrain gets beat up temporarily.

[ljmac75]

I didn't see the high altitude of the plane earlier when reporting FL winds. Sorry if that misled anyone.

This drop is from the weaker NW eyewall, which still seems to show relatively good mixing down to the surface (as well as high FL/surface ratios).

https://i.postimg.cc/XYXN4c3k/MELISSA-NOAA2-2513A-dropsonde-202510282207.png

Here's the NE eyewall. While definitely not a major anymore, it probably doesn't change anything I said above fundamentally.

https://i.postimg.cc/k5dHfqjc/MELISSA-NOAA2-2513A-dropsonde-202510282214.png

Gusts to 60 knots currently being reported for Montego bay so this sounds reasonable.
They can't work on restoring the power lines till the wind subsides.

Cuba may luck out if we can get a little dry air entrained before landfall.

Where are you getting these obs for Montego bay?

[Nimbus]

Here's the NE eyewall. While definitely not a major anymore, it probably doesn't change anything I said above fundamentally.

https://i.postimg.cc/k5dHfqjc/MELISSA-NOAA2-2513A-dropsonde-202510282214.png

Gusts to 60 knots currently being reported for Montego bay so this sounds reasonable.
They can't work on restoring the power lines till the wind subsides.

Cuba may luck out if we can get a little dry air entrained before landfall.

Where are you getting these obs for Montego bay?

Weather Underground link updates every few minutes I've seen wind speeds as high as 75 knots in squalls.

https://www.wunderground.com/weather/jm/montego-bay

[dukeblue219]

AF recon looks to be back airborne

[zzzh]

There was definitely some sort of ERC going on with Melissa while inside Jamaica.

[ljmac75]

Gusts to 60 knots currently being reported for Montego bay so this sounds reasonable.
They can't work on restoring the power lines till the wind subsides.

Cuba may luck out if we can get a little dry air entrained before landfall.

Where are you getting these obs for Montego bay?

Weather Underground link updates every few minutes I've seen wind speeds as high as 75 knots in squalls.

https://www.wunderground.com/weather/jm/montego-bay

Looks like it's just model output, nearest station hasn't reported since very early this morning.

[LarryWx]

Good news for Cuba but man the core got destroyed. We’re gonna be getting Erin post-ERC ratios now aren’t we. Also cuts down on the remaining ACE forecasted so it doesn’t seem like Melissa will beat Erin in terms of ACE as I don’t think it’ll regain major, and in fact the mountains of Cuba probably screw with it to the point it comes out the other side a sloppy Cat 1 or low-end 2, not the major NHC currently has tracking through there.

With Melissa headed to ~27.25 as of 0Z this evening, it will then be only 5 lower than Erin. I see very little chance (5%) that it won’t get an additional >5 ACE the next 96 hours before extratropical transition. Thus I feel quite confident that Melissa’s ACE will exceed Erin’s 32.2.

We’re now at 123.81 season to date with low 130s+ highly likely through Melissa.

[Nimbus]

Where are you getting these obs for Montego bay?

Weather Underground link updates every few minutes I've seen wind speeds as high as 75 knots in squalls.

https://www.wunderground.com/weather/jm/montego-bay

Looks like it's just model output, nearest station hasn't reported since very early this morning.

So you think the gusts being updated and changing every 5 minutes is just for show?
The airport closed this morning and there are internet connection outages all over the island but Weather Underground is usually connected to something.

The airport normally needs to have up to the minute wind speed information for take offs and landings. 5 or 10 mph wrong and you can cause an excursion.

[Ubuntwo]

Based on an analysis of recon data (TDR/HDOBs) and Cuban radar, I estimate that Josh's location in Crawford did see a brief pause in precip, but with gusty mesovortex winds to hurricane force. The location may have had glimpses of the stadium effect at times. His pressure observation won't be directly representative of the landfall intensity - at his distance from the eye, pressures could have been as high as 910mb w/ a 892mb landfall. The gradient was extremely sharp! Pressures above this could suggest some weakening prior to landfall, and pressures 900mb and below would at the very least confirm an 892mb landfall intensity & imply that it may have been stronger. Let's hope he had a barometer set up further west.

[Blown Away]

Based on an analysis of recon data (TDR/HDOBs) and Cuban radar, I estimate that Josh's location in Crawford did see a brief pause in precip, but with gusty mesovortex winds to hurricane force. The location may have had glimpses of the stadium effect at times. His pressure observation won't be directly representative of the landfall intensity - at his distance from the eye, pressures could have been as high as 910mb w/ a 892mb landfall. The gradient was extremely sharp! Pressures above this could suggest some weakening prior to landfall, and pressures 900mb and below would at the very least confirm an 892mb landfall intensity & imply that it may have been stronger. Let's hope he had a barometer set up further west.

Josh M was literally on the E edge of that eyewall. I was hoping he would see the stadium since he documents these storms so amazingly well.

[Ubuntwo]

So you think the gusts being updated and changing every 5 minutes is just for show?
The airport closed this morning and there are internet connection outages all over the island but Weather Underground is usually connected to something.

The airport normally needs to have up to the minute wind speed information for take offs and landings. 5 or 10 mph wrong and you can cause an excursion.

They have a history section for the airport station and the most recent observation is from 5 AM, despite regularly updating "current conditions":


NWS also has direct obs from the airport & the most recent one is from 5 AM as well.
https://forecast.weather.gov/data/obhistory/MKJS.html

I would agree that Wunderground appears to be displaying model outputs. Though I would be surprised if Montego Bay saw conditions exceeding category 2 due to the rapid deterioration we observed.

[Nimbus]

Based on an analysis of recon data (TDR/HDOBs) and Cuban radar, I estimate that Josh's location in Crawford did see a brief pause in precip, but with gusty mesovortex winds to hurricane force. The location may have had glimpses of the stadium effect at times. His pressure observation won't be directly representative of the landfall intensity - at his distance from the eye, pressures could have been as high as 910mb w/ a 892mb landfall. The gradient was extremely sharp! Pressures above this could suggest some weakening prior to landfall, and pressures 900mb and below would at the very least confirm an 892mb landfall intensity & imply that it may have been stronger. Let's hope he had a barometer set up further west.

Southern shore of west Jamaica is a disaster area now, he must have been caught up helping with search and rescue. Maybe upload some video tonight?

[MEANINGLESS_NUMBERS]

Is that an eye coming out? If the mid-level core survived the mountains and drills down the surface we could be off to the races again.

[Ubuntwo]

Based on an analysis of recon data (TDR/HDOBs) and Cuban radar, I estimate that Josh's location in Crawford did see a brief pause in precip, but with gusty mesovortex winds to hurricane force. The location may have had glimpses of the stadium effect at times. His pressure observation won't be directly representative of the landfall intensity - at his distance from the eye, pressures could have been as high as 910mb w/ a 892mb landfall. The gradient was extremely sharp! Pressures above this could suggest some weakening prior to landfall, and pressures 900mb and below would at the very least confirm an 892mb landfall intensity & imply that it may have been stronger. Let's hope he had a barometer set up further west.

Southern shore of west Jamaica is a disaster area now, he must have been caught up helping with search and rescue. Maybe upload some video tonight?

I hope he's alright. The entire parish is without internet/electricity, so he will need to wait on access to Starlink or the like before any uploads. I would concur disaster response is probably his priority at the moment. Crawford saw the RMW for over an hour.

Josh M was literally on the E edge of that eyewall. I was hoping he would see the stadium since he documents these storms so amazingly well.

Crawford was balanced on the razor's edge. +- .5 miles would have made the difference. Parallax, inward slope of the eye, and mesovortex timing makes it really tough to say whether he saw the stadium or not.

[Hurrilurker]

Jamaica's terrain really put the clamps on it more than I expected for a relatively short pass, but it looks like it's recovering quickly offshore. Wouldn't be surprised to see it get back down to the 940s.

[Nimbus]

So you think the gusts being updated and changing every 5 minutes is just for show?
The airport closed this morning and there are internet connection outages all over the island but Weather Underground is usually connected to something.

The airport normally needs to have up to the minute wind speed information for take offs and landings. 5 or 10 mph wrong and you can cause an excursion.

They have a history section for the airport station and the most recent observation is from 5 AM, despite regularly updating "current conditions":
https://i.imgur.com/BSPiIyS.png

NWS also has direct obs from the airport & the most recent one is from 5 AM as well.
https://forecast.weather.gov/data/obhistory/MKJS.html

I would agree that Wunderground appears to be displaying model outputs. Though I would be surprised if Montego Bay saw conditions exceeding category 2 due to the rapid deterioration we observed.

Its not model output changing every couple minutes.
Would have to be an elaborate hoax on the part of Weather Underground.
Just changed again and I'm thinking the airport just stopped updating their web page and left their wind speed observations connected to Weather Underground?