ATL: LORENZO - Post-Tropical - Discussion

[1900hurricane]

 https://twitter.com/1900hurricane/status/1178509784259141632



 https://twitter.com/1900hurricane/status/1178511026024845312

[CrazyC83]

What are the upper level environmental temperatures like? Could this maintain itself over cooler water with greater instability (i.e. colder aloft)?

[1900hurricane]

What are the upper level environmental temperatures like? Could this maintain itself over cooler water with greater instability (i.e. colder aloft)?

Upper level temperatures surrounding Lorenzo are warmer than the environment would be otherwise due to outflow from the system's deep warm core. Once it moves over colder waters, it would need to depend on baroclinic influences (i.e. begin transitioning to a hybrid or extratropical cyclone) to keep from falling apart. Systems that can maintain themselves over marginal waters due to cold temperatures aloft have more shallow warm cores.



Using phase space from the 18Z GFS, the warm core does transition from deep to shallow, but that's a result of taking on baroclinic influences (becoming very asymmetric).

[TallyTracker]

Lorenzo’s TS winds are now about 500 miles across...(255 miles out from center based on 8 am advisory). How large is the hurricane supposed to get before ET transition is complete?

[CrazyC83]

Lorenzo’s TS winds are now about 500 miles across...(255 miles out from center based on 8 am advisory). How large is the hurricane supposed to get before ET transition is complete?

You can probably add at least another 100 miles in each direction.

[Astromanía]

Lorenzo will be lowered to a category 4 at peak intensity in post season analisys? or its peak intensity will stay as a categoiry 5? based on dvorak I think there is more reasons to lower its peak intensity, but I don´t think they will do it.

[TropicalAnalystwx13]

Lorenzo will be lowered to a category 4 at peak intensity in post season analisys? or its peak intensity will stay as a categoiry 5? based on dvorak I think there is more reasons to lower its peak intensity, but I don´t think they will do it.

Satellite intensity estimates from the agencies NHC most commonly uses, SAB, TAFB, and UW-CIMSS ADT, were a consensus T7.0/140kt. The chance Lorenzo is downgraded is near 0%.

[Ubuntwo]

Lorenzo will be lowered to a category 4 at peak intensity in post season analisys? or its peak intensity will stay as a categoiry 5? based on dvorak I think there is more reasons to lower its peak intensity, but I don´t think they will do it.

Dvorak was T7.0 but most microwave estimates were lower than that. I think they keep it for record's sake and, after all, for the other recon flights the intensity was in line with Dvorak. They lowered the best track to 135kt but it seems likely they make the cat 5 peak a point in between those 6-hour intervals.

[Hammy]

Lorenzo will be lowered to a category 4 at peak intensity in post season analisys? or its peak intensity will stay as a categoiry 5? based on dvorak I think there is more reasons to lower its peak intensity, but I don´t think they will do it.

Satellite intensity estimates from the agencies NHC most commonly uses, SAB, TAFB, and UW-CIMSS ADT, were a consensus T7.0/140kt. The chance Lorenzo is downgraded is near 0%.

I do wonder if the BT change means they'll have an extra position indicating it attained Cat 5 advisory between positions, so for the 03z position.

[Kazmit]

It's certainly maintaining it's satellite appearance this evening. Might even be a bit better than earlier today.

[Chris90]

NHC upgraded Lorenzo to Cat 5 with surprising ease in my opinion. EPAC storms have to work a lot harder than that to get the classification.

But if Lorenzo is a Cat 5, then Hector at least deserves the upgrade. Recon got a 137kt SFMR when they flew that storm as well as flagged SFMR values as high as 153kts. His satellite appearance at peak was pretty fantastic, and his microwave presentation was pretty great at peak as well. Norman is a bit less of a sure thing in my opinion, but still worthy of the upgrade, and you might even be able to throw in Rosa from last year too.
I can't help but feel like a major reason Lorenzo got the upgrade was because of his history making position. If he was an EPAC storm I think he would also be stuck in the 135kt purgatory. Just my opinion though.

[CrazyC83]

Indeed it looks better than it has at any time in the last 24-36 hours. Could it intensify on the way to the Azores? AFAIK, no major hurricane has ever hit the region.

[Astromanía]

NHC upgraded Lorenzo to Cat 5 with surprising ease in my opinion. EPAC storms have to work a lot harder than that to get the classification.

But if Lorenzo is a Cat 5, then Hector at least deserves the upgrade. Recon got a 137kt SFMR when they flew that storm as well as flagged SFMR values as high as 153kts. His satellite appearance at peak was pretty fantastic, and his microwave presentation was pretty great at peak as well. Norman is a bit less of a sure thing in my opinion, but still worthy of the upgrade, and you might even be able to throw in Rosa from last year too.
I can't help but feel like a major reason Lorenzo got the upgrade was because of his history making position. If he was an EPAC storm I think he would also be stuck in the 135kt purgatory. Just my opinion though.

You are right, that's why I'm mad about this upgrade. Why should ATL have an special treat when its an objetively classification? It was already an impressive cat 4 storm you don't need to upgrade an hurricane to a cat 5 when it was like less than an hour at that intensity, if they will do that, then many storms from the past should be upgraded, this is only an opinion, I don't try to ofend anyone

[Ubuntwo]

NHC upgraded Lorenzo to Cat 5 with surprising ease in my opinion. EPAC storms have to work a lot harder than that to get the classification.

But if Lorenzo is a Cat 5, then Hector at least deserves the upgrade. Recon got a 137kt SFMR when they flew that storm as well as flagged SFMR values as high as 153kts. His satellite appearance at peak was pretty fantastic, and his microwave presentation was pretty great at peak as well. Norman is a bit less of a sure thing in my opinion, but still worthy of the upgrade, and you might even be able to throw in Rosa from last year too.
I can't help but feel like a major reason Lorenzo got the upgrade was because of his history making position. If he was an EPAC storm I think he would also be stuck in the 135kt purgatory. Just my opinion though.

You are right, that's why I'm mad about this upgrade. Why should ATL have an special treat when its an objetively classification? It was already an impressive cat 4 storm you don't need to upgrade an hurricane to a cat 5 when it was like less than an hour at that intensity, if they will do that, then many storms from the past should be upgraded, this is only an opinion, I don't try to ofend anyone

Someone on twitter, maybe an NHC forecaster, said that the significantly lower troposphere heights in this part of the world mean that cloud tops like Lorenzo had were significantly more impressive and more likely to indicate higher winds than in, say, the Caribbean or Pacific.

[Hypercane_Kyle]

NHC upgraded Lorenzo to Cat 5 with surprising ease in my opinion. EPAC storms have to work a lot harder than that to get the classification.

Not really, see Igor in 2010 and Joaquin in 2015.

Lorenzo ticked all the marks that Cody mentioned. Clear cut Category 5, IMO.

[1900hurricane]

Worth noting that if you venture into NHC's f-deck for Lorenzo, NHC/TAFB actually edited their special 0130Z Dvorak fix from 7.0 to 6.5. Coupled with SAB's 7.0 on the same special 0130Z fix, that is probably the reason for the drop to 135 kt from 140 kt. Based on this, I don't think 140 kt is as sure as some think.

AL, 13, 201909290130, 10, DVTS, CI, , 2380N, 4480W, , 1, 127, 2, , , , , , , , , , , , , , , , , , NHC, AL, I, 1, 6565 /////, , , GOES16, LLCC, T, Correction - Original fix of 7.0/7.0 broke constrain
AL, 13, 201909290130, 10, DVTS, CI, , 2400N, 4480W, , 1, 140, 2, , , , , , , , , , , , , , , , , L, SAB, MT, IM, 1, 7070 /////, , , GOES16, LLCC, T, DT=7.0 BO EYE MET=X.X PT=X.X FTBO DT

[somethingfunny]

A sad update on the Bourbon Rhode sinking as one body was recovered yesterday. 10 sailors remain missing.

https://www.google.com/amp/s/www.foxnew ... inique.amp

[Astromanía]

I knew I had a bad feeling, is not good that there are still 10 people there missing

[supercane4867]

[Emmett_Brown]

Lorenzo is one of the larger ATL Hurricanes you will see; per the 11am advisory:

"Hurricane-force winds extend outward up to 90 miles (150 km) from
the center and tropical-storm-force winds extend outward up to 345
miles (555 km)."

It's YUGE...