ATL: SAM - Remnants - Discussion

[AlphaToOmega]

Now at 60 knots

AL, 18, 2021092400, , BEST, 0, 111N, 403W, 60, 997, TS, 50, NEQ, 20, 0, 0, 10, 1012, 120, 15, 0, 0, L, 0, , 0, 0, SAM, D, 0, , 0, 0, 0, 0, genesis-num, 038,

[GCANE]

This will be approaching the islands under the best looking ARWB I have seen in a long time.

How high do you think the ceiling is for Sam, and what are your comment on the potential TUTT and bit of shear early next week?

Haven't looked too closely at this yet.
Not a lot of CAPE ahead of it and TPW feed doesn't look all that great.
Probably a low Cat 3 near the Bahamas.
At that point high OHC will play the key role for further intensification.

Later when it transitions could be the more worst-case scenario.
Would hate to see New England take a hit.

Would love to hear your thoughts.

[GCANE]

Current IR satellites estimating 55 knt winds.

[aspen]

This will be approaching the islands under the best looking ARWB I have seen in a long time.

How high do you think the ceiling is for Sam, and what are your comment on the potential TUTT and bit of shear early next week?

Haven't looked too closely at this yet.
Not a lot of CAPE ahead of it and TPW feed doesn't look all that great.
Probably a low Cat 3 near the Bahamas.
At that point high OHC will play the key role for further intensification.

Later when it transitions could be the more worst-case scenario.
Would hate to see New England take a hit.

Would love to hear your thoughts.

IMO, the only things holding this back are slow movement later this weekend which would result in some upwelling, and any random unpredictable EWRC. The UL setup is excellent, and combined with low shear and moist air, Sam could attempt to reach the MPIs of its region.

This is my assessment of the region only in its 5-day cone btw. There’s too much uncertainty afterwards; I’m surprised you think it’ll get to the Bahamas.

[grapealcoholic]

It's done what looks like a whole day's worth of organizing in a few hours

[ElectricStorm]

Looks like Sam is exploding. Will likely be a major by midday tomorrow at this rate.

[WiscoWx02]

Convection now wrapping around the eye now, although it is a super small eye at that. Gonna take a few days to get a better structure but probably going to wake up to Hurricane Sam tomorrow morning at this rate.

[skyline385]

Look at those rotating towers near the centre

[GCANE]

How high do you think the ceiling is for Sam, and what are your comment on the potential TUTT and bit of shear early next week?

Haven't looked too closely at this yet.
Not a lot of CAPE ahead of it and TPW feed doesn't look all that great.
Probably a low Cat 3 near the Bahamas.
At that point high OHC will play the key role for further intensification.

Later when it transitions could be the more worst-case scenario.
Would hate to see New England take a hit.

Would love to hear your thoughts.

IMO, the only things holding this back are slow movement later this weekend which would result in some upwelling, and any random unpredictable EWRC. The UL setup is excellent, and combined with low shear and moist air, Sam could attempt to reach the MPIs of its region.

This is my assessment of the region only in its 5-day cone btw. There’s too much uncertainty afterwards; I’m surprised you think it’ll get to the Bahamas.

I am not saying into the Bahamas, more like skirting east of the Bahamas.
It'll curve from the Coriolis differential. However, not seeing any strong steering patterns until it gets close to the Rossby Wave which is too far out too make any type of accurate estimate at this time.

[Nimbus]

Near the Bahamas usually means near Puerto Rico and we are starting to get in model range of forecast that would effect the islands.

[Stormybajan]

Now at 60 knots

AL, 18, 2021092400, , BEST, 0, 111N, 403W, 60, 997, TS, 50, NEQ, 20, 0, 0, 10, 1012, 120, 15, 0, 0, L, 0, , 0, 0, SAM, D, 0, , 0, 0, 0, 0, genesis-num, 038,

WOW. And at the rate its intensifying right now, by 11 pm NHC may actually go with a hurricane

[Shell Mound]

Looks like Sam is exploding. Will likely be a major by midday tomorrow at this rate.

The ongoing spate of (E)RI will almost certainly contribute to eastward shifts in the guidance and allow Sam to miss the Leeward Islands, however narrowly. The strongest EPS and GEFS members have consistently taken Sam to the northeast of the Islands. Given that Sam is intensifying even more rapidly than either these or the intensity guidance indicated, the likelihood of an OTS trajectory increases tremendously. Ridging is not expected to be particularly strong, hence’s Sam relatively slow forward speed through D5. The only factor that will prevent Category-5 status at this point is the marginal thermodynamic environment, but otherwise all other indicators favour yet another powerful annular MH in D3–5. Expect Sam to be a stronger version of Larry.

[Nuno]

[InfernoFlameCat]

Yeah this thing is going super. Those waters have not been tapped by anything besides Elsa. Also Elsa was just a wave at that point. What a beast this thing is becoming.

[Shell Mound]

This will be approaching the islands under the best looking ARWB I have seen in a long time.

How high do you think the ceiling is for Sam, and what are your comment on the potential TUTT and bit of shear early next week?

 https://twitter.com/AndyHazelton/status/1441142303112925192

[galaxy401]

Sam is looking very impressive tonight. There isn't much in the way for it during the next few days. Hard to say if its a hurricane yet but it's about to be.

[supercane4867]

One thing to note: the euro has been consistently implying a potential SW dive during Sam's closest approach to the islands (it was more pronounced a few runs ago but still possible given how quickly the ridge rebuilds), which reminiscent of Irma albeit at a higher latitude. We all know SW dives by intense TCs almost always manage to produce the worst outcomes in the NHEM basins

[Teban54]

It's fascinating to watch Sam consistently producing tiny rotating hot towers. IMO this is likely a hurricane already.

[ScottNAtlanta]

Looks like Sam is exploding. Will likely be a major by midday tomorrow at this rate.

The ongoing spate of (E)RI will almost certainly contribute to eastward shifts in the guidance and allow Sam to miss the Leeward Islands, however narrowly. The strongest EPS and GEFS members have consistently taken Sam to the northeast of the Islands. Given that Sam is intensifying even more rapidly than either these or the intensity guidance indicated, the likelihood of an OTS trajectory increases tremendously. Ridging is not expected to be particularly strong, hence’s Sam relatively slow forward speed through D5. The only factor that will prevent Category-5 status at this point is the marginal thermodynamic environment, but otherwise all other indicators favour yet another powerful annular MH in D3–5. Expect Sam to be a stronger version of Larry.

I don't think that it is certain at all this is going out. The speed at which it is traveling is much more of an issue than how strong it is. If its a 70kt storm or a 120kt storm it is still going to follow the same steering. I think we need to pay very close attention as to whether this is hitting track forecast points and if it is off...which direction

[Spacecoast]

Latest Multi - model diagnostic plot from 18z runs(updated 9-24 0z)
ECMF lags in intensity?