ATL: SAM - Remnants - Discussion

[Subtrop]

AL, 18, 2021092512, , BEST, 0, 128N, 472W, 105, 965, HU, 34, NEQ, 50, 40, 30, 50, 1013, 120, 15, 0, 0, L, 0, , 0, 0, SAM, D, 0, , 0, 0, 0, 0, genesis-num, 038,
AL, 18, 2021092512, , BEST, 0, 128N, 472W, 105, 965, HU, 50, NEQ, 30, 25, 15, 25, 1013, 120, 15, 0, 0, L, 0, , 0, 0, SAM, D, 0, , 0, 0, 0, 0, genesis-num, 038,
AL, 18, 2021092512, , BEST, 0, 128N, 472W, 105, 965, HU, 64, NEQ, 15, 15, 10, 15, 1013, 120, 15, 0, 0, L, 0, , 0, 0, SAM, D, 0, , 0, 0, 0, 0, genesis-num, 038,

[Zonacane]

Major hurricane number 4

[tolakram]

When you see the eye get obscured and cloud tops raising up it's sometimes the start of an intensification phase. Could be an ERC starting as well, we'll have to see.

[cycloneye]

Has it taken a temporary west jog?

I said the above at 5:04 AM and it continued with the west jog that now best track position is 12.8N, the same as the 5 AM advisory.

[zal0phus]

I wonder if they’re going to completely miss Sam’s obvious peak intensity from earlier this morning and not upgrade it to a major.

[AlphaToOmega]

I wonder if they’re going to completely miss Sam’s obvious peak intensity from earlier this morning and not upgrade it to a major.

Sam has already been upgraded.

[dexterlabio]

It looks tilted or stretched from NW to SE?

[Hypercane_Kyle]

I don't think we're seeing an EWRC. More likely some mid-level shear is creeping in.

[aspen]

This has likely weakened since the 5am advisory and was probably a stronger major then, but at least it got upgraded. That’s 19/7/4 by September 25th, between 2020’s and 2005’s paces in terms of NS/H and ahead of 2020 in terms of majors — and we still have a Nina-enhanced October ahead of us.

[Blinhart]

Upper-Level Steering is favoring due west into the Caribbean, especially the Triangle Ridge at 700-850 MB

200-700 MB
https://s9.gifyu.com/images/wg8dlm670a9a5d5bd581368.gif

700-850 MB
https://s9.gifyu.com/images/wg8dlm14bf2cbdaa02bdfd3.gif

Been looking like that for me the whole time, so was wondering what the models have been seeing for the past week.

[Blinhart]

When you see the eye get obscured and cloud tops raising up it's sometimes the start of an intensification phase. Could be an ERC starting as well, we'll have to see.

https://i.imgur.com/xXH4Bht.png

looks like he is actually trying to expand his size right now, getting the outflow on all sides, just need the SW side to fill out, then we will see him start his RI again.

[kevin]

Yes Sam has weakened for now, but note how most models and guidance don't show Sam peaking until roughly Monday. In fact none of the models even forecast this phase of ERI (at least not to this extent) that probably brought Sam to ~120 kt a few hours ago. So while Sam has taken a breather for now, I don't think we've seen it at peak intensity yet, especially if it can catch that anti-cyclone.

[Iceresistance]

The Anticyclone is to the West of Sam, if he can just catch up to it & latch on . . .



I've also noticed that the slight SW Shear is being caused by the Anticyclone

[Teban54]

How the hell did Sam suddenly wrap a full W ring during what appears to be a weakening or EWRC phase?

[Iceresistance]

The SW Shear is not strong enough to limit Sam from achieving the full W Ring, the Conditions are also very favorable for something like this to occur . . .

[Iceresistance]

Consistent Lightning has been detected in the NW Eyewall . . .

[Blinhart]

Consistent Lightning has been detected in the NW Eyewall . . .

So he could still be strengthening, or going through a small EW expansion.

[Owasso]

UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 9.0
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 25 SEP 2021 Time : 132020 UTC
Lat : 12:55:12 N Lon : 47:23:23 W


CI# /Pressure/ Vmax
6.0 / 952.8mb/115.0kt


Final T# Adj T# Raw T#
5.3 4.9 4.9

Estimated radius of max. wind based on IR : 9 km

Center Temp : -27.0C Cloud Region Temp : -57.2C

Scene Type : EYE

Subtropical Adjustment : OFF

Extratropical Adjustment : OFF

Positioning Method : ARCHER POSITIONING

Ocean Basin : ATLANTIC
Dvorak CI > MSLP Conversion Used : CKZ Method

Tno/CI Rules : Constraint Limits : NO LIMIT
Weakening Flag : ON
Rapid Dissipation Flag : FLAG

C/K/Z MSLP Estimate Inputs :
- Average 34 knot radii : 42nmi
- Environmental MSLP : 1013mb

Satellite Name : GOES16
Satellite Viewing Angle : 35.4 degrees

[NDG]

The Anticyclone is to the West of Sam, if he can just catch up to it & latch on . . .

https://s9.gifyu.com/images/wg8shr3d6a60d52450ec36.gif

I've also noticed that the slight SW Shear is being caused by the Anticyclone

I don't know why a shear map is used by some of you to locate an Anticylone, the best method to use a map of UL winds.
The anticyclone closest to Sam is actually just to the east of it with another one north of the Leeward Islands. The GFS shows Sam catching up to that one in 72 hrs.

[NDG]

Officially now MH.

 https://twitter.com/NHC_Atlantic/status/1441774506062663680