Eastern Pacific Basin Tropical Cyclones

Tropical Storm Newton Forecast Discussion


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Tropical Storm Newton Discussion Number   3
NWS National Hurricane Center Miami FL       EP152022
300 AM MDT Thu Sep 22 2022

Newton is a small, but well-organized tropical cyclone. The earlier
banding pattern has now evolved more into a very small central
dense overcast. While we have not received any recent microwave or
scatterometer data in the last 6 hours, the earlier GPM pass at 2207
UTC suggested a formative inner core was taking shape. Satellite
intensity estimates cover a large range this morning, from
T2.5/35-kt from SAB, T3.5/55-kt from TAFB, and T2.8/41-kt from
UW-CIMSS ADT. Favoring the higher end of those estimates, the
initial intensity was raised to 50-kt for this advisory.

Newton continues to move to the west-northwest but is beginning to
slow down somewhat, with the latest estimate at 285/8 kt. This
general motion with an additional slow down in forward motion is
expected over the next 24-36 hours as the system remains steered by
a prominent mid-level ridge to the northeast. The NHC track this
cycle was adjusted ever so slightly faster, but remains close to
the tightly clustered consensus aids.

The intensity forecast is a bit tricky for Newton. The storm is very 
small, and has not been recently sampled by scatterometer or 
microwave imagery, so it is unclear if the inner core structure seen 
earlier on microwave yesterday evening has persisted. Vertical wind 
shear, as diagnosed by the GFS and ECMWF-based SHIPS is expected to 
remain at or under 10 kts for the next 2-3 days. However, the 
tropical cyclone will be moving over the cold wake induced by 
Hurricane Kay and more recently Tropical Storm Madeline over the 
last several weeks. Sea-surface temperatures (SSTs) drop below 26 C 
in around 24 hours. The global models respond to this environment by 
showing all convection collapsing near Newton in 24-48 hours and it 
seems that the small circulation will not be able to survive these 
anomalously cold SSTs. Then again, the cyclone is so small, the 
guidance may not be resolving the current structure of the cyclone 
well. Thus the latest NHC intensity forecast calls for a little bit 
of additional intensification today, similar to the SHIPS guidance 
in the short-term. After that, the cooler SSTs should induce a 
weakening trend, and Newton is still expected to become a 
post-tropical remnant low by 60 hours, continuing to blend the 
dynamical and statistical intensity aids.

FORECAST POSITIONS AND MAX WINDS

INIT  22/0900Z 17.7N 107.8W   50 KT  60 MPH
 12H  22/1800Z 18.0N 109.1W   55 KT  65 MPH
 24H  23/0600Z 18.2N 110.5W   50 KT  60 MPH
 36H  23/1800Z 18.6N 112.0W   45 KT  50 MPH
 48H  24/0600Z 19.2N 113.5W   40 KT  45 MPH
 60H  24/1800Z 19.3N 115.0W   30 KT  35 MPH...POST-TROP/REMNT LOW
 72H  25/0600Z 19.3N 116.5W   25 KT  30 MPH...POST-TROP/REMNT LOW
 96H  26/0600Z...DISSIPATED

$$
Forecaster Papin

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