ATL: NIGEL - Post-Tropical - Discussion

[WalterWhite]

I still think this will become a major hurricane. SSTs are still very warm in 15L's projected path.

[aspen]

12z hurricane models are generally showing a pretty broad core, which would likely prevent this from becoming too strong. Of the four models, only the HWRF has it becoming a major. Not surprised the NHC bumped the peak down slightly, although this becoming a major is still very possible (maybe even likely)

18z runs are about to start, we'll see if they're similar to the 12z runs

The HAFS models showing a large core is pretty telling, as unlike the HWRF, they don’t have a big core bias. I think we’ll see something similar to Larry ‘21: a low-end major with a giant eye.

[cycloneye]

THe squadron has been very busy this season and looks like it will continue that way with this Tropical Cyclone.

POSSIBLY BEGIN FIXES ON TROPICAL
DEPRESSION FIFTEEN AT 18/1730Z.

[Sciencerocks]

[zzzh]

ASCAT shows a broad structure. Needs to tighten up.

[abajan]

Best Track:

AL, 15, 2023091612, , BEST, 0, 191N, 458W, 30, 1006, TD

Central pressure has dropped a millibar and the CoC has moved NNW from its previous estimated position:

AL, 15, 2023091606, , BEST, 0, 172N, 450W, 30, 1007, TD

Source: https://ftp.nhc.noaa.gov/atcf/btk/bal152023.dat

[ChrisH-UK]

TD 15 is stretched out into a oval with most of the convection been at the northern end. As the convection builds it should coalesce at the northern end which seems to of started to happen.

Source - https://col.st/qU7me

[cycloneye]

THe squadron has been very busy this season and looks like it will continue that way with this Tropical Cyclone.

POSSIBLY BEGIN FIXES ON TROPICAL
DEPRESSION FIFTEEN AT 18/1730Z.

There will be no recon for this system as it will move well east of Bermuda. The above from Fridays TCPOD has been canceled.

[Sciencerocks]

[Sciencerocks]

[Landy]

AL, 15, 2023091700, , BEST, 0, 215N, 476W, 35, 1005, TS

[Hurricane2022]

AL, 15, 2023091700, , BEST, 0, 215N, 476W, 35, 1005, TS

After 6 years Nigel finally is a TS!!!

[Sciencerocks]

[cycloneye]

...TROPICAL STORM NIGEL FORMS IN THE CENTRAL ATLANTIC...
...EXPECTED TO BECOME A HURRICANE ON MONDAY.

[Hurricane2022]

000
WTNT35 KNHC 170240
TCPAT5

BULLETIN
Tropical Storm Nigel Advisory Number 7
NWS National Hurricane Center Miami FL AL152023
1100 PM AST Sat Sep 16 2023

...TROPICAL STORM NIGEL FORMS IN THE CENTRAL ATLANTIC...
...EXPECTED TO BECOME A HURRICANE ON MONDAY...


SUMMARY OF 1100 PM AST...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...22.0N 48.0W
ABOUT 980 MI...1580 KM ENE OF THE LESSER ANTILLES
MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H
PRESENT MOVEMENT...NW OR 325 DEGREES AT 16 MPH...26 KM/H
MINIMUM CENTRAL PRESSURE...1005 MB...29.68 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.


DISCUSSION AND OUTLOOK
----------------------
The satellite presentation of the cyclone has improved this evening
as there has been an increase in convective banding over the
northern portion of the circulation. The center appears to be
located near the southern portion of the convective mass. Dvorak
Data T-numbers from both SAB and TAFB were T2.5 (35 kt) at 0000 UTC
and objective satellite estimates from UW/CIMSS are in the 35 to 40
kt range. Based on these data, the initial intensity has been
raised to 35 kt. Nigel becomes the 10th named storm to form in
the Atlantic basin since August 20th.

Nigel is moving northwestward at about 14 kt. A mid-level ridge
to the northeast of the cyclone should steer the storm
northwestward during the next few days. After that time, Nigel is
expected to turn northward around the western side of the ridge. By
the middle of next week, the global model guidance indicates that
the storm should turn northeast ahead of a broad mid-latitude
trough over the western Atlantic. There is fairly good agreement
in the global model guidance on the overall scenario, but there are
some timing or forward speed difference later in the period. The
NHC forecast track is near the HFIP corrected consensus which is
close to a blend of the latest GFS and ECMWF models.

Environmental conditions are expected to be conducive for steady
intensification during the next few days, with low vertical wind
shear and warm sea surface temperatures along the forecast track.
A period of rapid intensification is is certainly possible within
the next two to three days. Although the SHIP RI probabilities are
not very high at the moment, DTOPS gives a 50 percent chance of a 65
kt increase in intensity during the next 72 hours. The NHC forecast
is close to that, showing a 60 kt increase in strength during the
time. After 72 hours, increasing southwesterly shear is likely to
cause gradual weakening. The NHC wind speed forecast is closest to
the HFIP corrected consensus.


FORECAST POSITIONS AND MAX WINDS

INIT 17/0300Z 22.0N 48.0W 35 KT 40 MPH
12H 17/1200Z 23.6N 49.2W 45 KT 50 MPH
24H 18/0000Z 25.3N 50.6W 55 KT 65 MPH
36H 18/1200Z 26.7N 52.2W 65 KT 75 MPH
48H 19/0000Z 27.8N 54.0W 75 KT 85 MPH
60H 19/1200Z 29.4N 55.7W 85 KT 100 MPH
72H 20/0000Z 31.3N 56.7W 95 KT 110 MPH
96H 21/0000Z 36.0N 55.6W 85 KT 100 MPH
120H 22/0000Z 41.9N 47.3W 80 KT 90 MPH

$$
Forecaster Brown

[galaxy401]

Wrapping up quicker now. Up to 45 kts on Best Track. Won't be surprised to see another major out of this.

[Sciencerocks]

[cycloneye]

Going up fast.

AL, 15, 2023091712, , BEST, 0, 235N, 488W, 50, 997, TS

[Kazmit]

Go Nigel go!

[Sciencerocks]