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Hurricane Felicia Discussion Number  18
NWS National Hurricane Center Miami FL       EP062021
500 AM HST Sun Jul 18 2021
 
Some changes have been seen with Felicia during the past several 
hours.  The eye is not quite as warm in satellite pictures, and 
there are banding features present in the eastern semicircle of the 
hurricane.  Overall, Felicia's previously very symmetric appearance 
has become a little distorted to the northeast. Both SAB and TAFB 
give an initial wind estimate of 115 kt, and that value is used for 
this advisory.
 
The big question is when will Felicia begin to weaken more 
significantly.  Any environmental changes are fairly subtle during 
the next couple of days, with somewhat cooler waters and a slight 
increase in upper-level shear likely.  While annular structure 
tends to be more stable, Felicia is a very small tropical cyclone, 
and those petite systems usually weaken quickly in marginal 
environments.  Additionally, the latest microwave data has some 
suggestion of the early stages of an eyewall cycle (although it 
showed the same thing yesterday without much impact).  All of these 
complex factors lead to this being a low confidence forecast during 
the next day or two.  The new intensity forecast is a bit lower 
than the previous one, owing to the recent degradation in 
structure, but is still above the guidance mean.  In about 3 days, 
much stronger shear should impact Felicia, leading to a quick death 
near or just after day 4.
 
Felicia is moving west-northwestward at about 10 kt.  The cyclone is 
expected to turn westward by Monday, then move west-southwestward 
through midweek as Felicia becomes steered by a large ridge across 
the central Pacific.  There is a little more spread in the guidance 
this morning, partially related to exactly how quickly Felicia 
weakens.  The ECMWF, for instance, shows a faster decrease in wind 
speed, and is more to the southwest of the other guidance, 
consistent with the low-level steering flow.  The GFS has the system 
moving slower and a little more poleward due to its stronger 
depiction of Felicia. The new forecast is slightly weighted toward 
the GFS solution, near the TCVN consensus, resulting in a small 
northward adjustment.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  18/1500Z 15.7N 128.1W  115 KT 130 MPH
 12H  19/0000Z 16.1N 129.6W  105 KT 120 MPH
 24H  19/1200Z 16.3N 131.7W   95 KT 110 MPH
 36H  20/0000Z 16.4N 133.9W   85 KT 100 MPH
 48H  20/1200Z 16.2N 136.3W   75 KT  85 MPH
 60H  21/0000Z 15.8N 139.0W   60 KT  70 MPH
 72H  21/1200Z 15.2N 141.6W   45 KT  50 MPH
 96H  22/1200Z 14.2N 146.8W   30 KT  35 MPH
120H  23/1200Z 13.5N 152.5W   25 KT  30 MPH...POST-TROP/REMNT LOW
 
$$
Forecaster Blake
 
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