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Tropical Storm Polo Discussion Number   4
NWS National Hurricane Center Miami FL       EP212020
700 AM PST Wed Nov 18 2020

Satellite images indicate that the depression has strengthened into 
a tropical storm.  The small central dense overcast has grown  
during the past several hours and a few banding features have 
formed.  Dvorak estimates range from 30 to 45 kt, and the initial 
wind speed is set to 40 kt, which matches the latest CIMSS 
satellite consensus estimate.  Polo could strengthen a little more 
today, but an increase in shear and dry-air entrainment should 
start the weakening process on Thursday, with the system expected 
to become a non-convective remnant low on Friday.  The new NHC 
forecast is a little below the model consensus, close to the 
previous NHC forecast, leaning toward the idea that the small 
tropical cyclone will probably weaken faster than the bulk of the 
guidance anticipates.
 
The initial motion continues to be west-northwestward at 10 kt.
There has been no change to the forecast philosophy, with Polo 
forecast to remain on the southern side of a mid-level ridge 
throughout the period.  The storm should turn more westward on 
Thursday as the system weakens and becomes more shallow.  The new 
forecast is south of the latest model consensus, nudged slightly 
north of the previous NHC forecast.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  18/1500Z 16.3N 116.0W   40 KT  45 MPH
 12H  19/0000Z 16.5N 117.6W   40 KT  45 MPH
 24H  19/1200Z 16.7N 119.6W   35 KT  40 MPH
 36H  20/0000Z 16.9N 121.5W   30 KT  35 MPH
 48H  20/1200Z 17.0N 123.6W   25 KT  30 MPH...POST-TROP/REMNT LOW
 60H  21/0000Z 17.0N 126.0W   25 KT  30 MPH...POST-TROP/REMNT LOW
 72H  21/1200Z...DISSIPATED
 
$$
Forecaster Blake
 
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