ATL: SAM - Remnants - Discussion

[cheezyWXguy]

This is easily the weakest-looking 130-kt system that I have seen on satellite, given lingering southwestern shear, the large, some what ragged eye, and the fairly warm, expansive CDO. Dorian, by contrast, was less sheared and far better organized. I wonder whether those FL winds are mixing to the surface. Also, 936 mb is a relatively high MSLP for a large 130-kt system at Sam's current cooordinates, near the subtropics. I am not a professional, of course, but maybe surface winds are lower than FL would suggest.

Looks pretty good to me

[grapealcoholic]

936 is lower than Laura's peak

[beoumont]

Quite a satellite study of an intense MATURE hurricane. One thing to my recollection: the relatively not-so-cold cloud tops in the central core is quite rare for such an intense system.

[cheezyWXguy]

It’s pretty amazing to me that there was not one, but 4 consecutive obs at or above 145kt FL. Usually you’re lucky to get a brief spike. Did any storm last year have FL winds this strong?

[grapealcoholic]

It's getting a huge boost from the trough via divergence; also there's stronger coriolisis effect at Sam's latitude

[Yellow Evan]

Way outrunning Dvorak here.

[Sciencerocks]

Is there any cat5's north of 26 and east of 70 and west of 50 in recorded history???

Closes
Dorian
Andrew
1938 hurricane
1932 Great bahama hurricane

[kevin]

Hopefully they can do one more NE pass, the strongest winds are clearly in quadrant.

[grapealcoholic]

Need some convection to wrap around that NE side

[bob rulz]

https://cdn.discordapp.com/attachments/733552978572869632/893385532648865822/image0.png

Way outrunning Dvorak here.

This shows just how vital recon is. Same with Dorian 2019. Dvorak is usually pretty close, but sometimes it's way off and it's important to understand why.

[kevin]

The most impressive thing about Sam is just how long he's been able to stay this strong despite forecast saying that he should weaken. An advisory from 3 days ago said that Sam should be weakening and back to 110 kt right now, but instead FL winds indicate that it's still a 130-135 kt monster.

[kevin]

Looks like recon is leaving. Next one arrives in 10 hours. I really thought Sam should be weakening by now, but he keeps surprising me so who knows what the next recon will find.

[kevin]

It’s pretty amazing to me that there was not one, but 4 consecutive obs at or above 145kt FL. Usually you’re lucky to get a brief spike. Did any storm last year have FL winds this strong?

Highest FL winds found in last year's MHs, all sourced from the official NHC reports. Thresholds are based on a 0.9 conversion factor.

--- cat 5 threshold = 152 kt
Laura = 148 kt
Sam (2021) = 147 kt
Iota = 147 kt
Eta = 137 kt
Delta = 132 kt
Teddy = 130 kt
--- cat 4 threshold = 126 kt
Zeta = 119 kt
Epsilon = 110 kt
--- cat 3 threshold = 107 kt

[kevin]

One of these is a 130 kt cat 4, the other one a 160 kt cat 5. If you didn't know which storms they are I can imagine you might accidentally assign the intensity the wrong way around. Sam is another case more similar to Dorian where the intensity outperforms the IR based estimates.

[grapealcoholic]

Of course Sam starts ripping after recon leaves lol

[Ubuntwo]

This is easily the weakest-looking 130-kt system that I have seen on satellite, given lingering southwestern shear, the large, some what ragged eye, and the fairly warm, expansive CDO. Dorian, by contrast, was less sheared and far better organized. I wonder whether those FL winds are mixing to the surface. Also, 936 mb is a relatively high MSLP for a large 130-kt system at Sam's current cooordinates, near the subtropics. I am not a professional, of course, but maybe surface winds are lower than FL would suggest.

KZC analysis for Sam right now comes out to 129.2kt.

[SteveM]

As others have mentioned, the cloud tops are warmer than one might expect. Do I see slight contraction of the eye, though?

[FLpanhandle91]

Warm eyes can do more for a storm than cold convection in a lot of cases.

[aspen]

I’m doubtful the next recon mission will still find a 130 kt Cat 4; Sam is probably down to 125 kt now IMO. Regardless, it’ll most likely hit 40 ACE sometime today, and the longer it holds on to Cat 4 status, the better shot it has at hitting 50 ACE.

[beoumont]

Is there any cat5's north of 26 and east of 70 and west of 50 in recorded history???

Closes
Dorian
Andrew
1938 hurricane
1932 Great bahama hurricane

Hurricane Esther 1961. 26.4 n / 68.9 w. 150 mph sustained, gusts 175-200. Gales extend 350 miles NE, 200 SW. Hurricane winds 170 miles NE, 110 SW.

<<<<However, reanalysis as part of the Atlantic hurricane reanalysis project concluded that Esther was in fact a Category 5 hurricane with winds of 160 mph (260 km/h) and a minimum pressure of 919 mbar (91.9 kPa; 27.1 inHg); this has now been officially incorporated into HURDAT.[6]>>>>>>

On September 16, a Navy plane flew into the eye of Esther about 400 miles (644 km) northeast of Puerto Rico, and dropped canisters of silver iodide into the storm. (not spinach, Popeye.) hurricane appeared to weaken slightly in response to the seeding, reportedly by ten percent. This weakening was temporary, however, as the hurricane resumed strengthening shortly after