Eastern Pacific Basin Tropical Cyclones

Tropical Storm Newton Forecast Discussion


000
WTPZ45 KNHC 220245
TCDEP5

Tropical Storm Newton Discussion Number   2
NWS National Hurricane Center Miami FL       EP152022
900 PM MDT Wed Sep 21 2022

The satellite presentation of the recently formed Tropical 
Depression Fifteen has improved considerably during the past 24 
hours. A well defined banding structure has developed and held in 
place during the past several hours, with nice outflow evident 
aloft in satellite imagery. The latest intensity estimates from TAFB 
and SAB were 35 knots, while ADT and AiDT from UW-CIMSS indicating 
slightly lower. These intensity estimates appear to be a bit behind 
the curve given the banding structure and organization seen in 
recent microwave imagery. In fact, TAFB provided a Dvorak pattern 
T-number of 3.0 (45 kt), which is the basis for the initial 
intensity of this advisory. 

The initial motion estimate on Newton is to the west-northwest 
or 285/11 kt. This general motion with a gradual slowing in the 
forward speed is expected during the next several days as the 
cyclone is steered by a mid-level ridge to the northeast and a 
weakness aloft to the west associated with the remnants of former 
tropical cyclone Madeline. The NHC track forecast was adjusted 
slightly faster and a bit north of the previous forecast, and is 
close to the tightly clustered consensus track guidance.

Environmental conditions appear favorable for some additional 
strengthening tonight and Wednesday, as vertical wind shear remains 
low, mid-levels moist, and sea surface temperatures (SSTs) remain at 
27/28C. Beyond this, while shear remains low, the mid-levels dry out 
considerably and SSTs decrease to near 26C. This should lead to 
steady weakening with Newton degenerating into a post-tropical 
remnant low Friday night or Saturday, and dissipating shortly 
thereafter. The NHC intensity forecast has been adjusted upward to 
account for the increase in initial intensity, and is roughly 
between the statistical and dynamical intensity aids.


FORECAST POSITIONS AND MAX WINDS

INIT  22/0300Z 17.6N 107.0W   45 KT  50 MPH
 12H  22/1200Z 18.0N 108.2W   50 KT  60 MPH
 24H  23/0000Z 18.3N 109.6W   50 KT  60 MPH
 36H  23/1200Z 18.6N 110.7W   50 KT  60 MPH
 48H  24/0000Z 18.9N 111.9W   40 KT  45 MPH
 60H  24/1200Z 19.3N 113.3W   30 KT  35 MPH...POST-TROP/REMNT LOW
 72H  25/0000Z...DISSIPATED

$$
Forecaster Brown/Jelsema



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