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Hurricane Linda Discussion Number  35
NWS National Hurricane Center Miami FL       EP122021
1100 AM HST Wed Aug 18 2021
 
Since the time of the previous advisory, satellite images show that 
Linda's cloud tops have warmed and are less prevalent on its west 
side. Visible imagery has also shown an increase in the low-level 
cloud cover inside the eye, though Linda still displays a fairly 
well-defined eye in infrared imagery. Dvorak T-numbers from TAFB and 
SAB have decreased, and the initial intensity has been lowered to 85 
kt for this advisory. 

Linda is currently over SSTs near 26 C, but SSTs along the path of 
the cyclone will decrease to below 25 C in about 6 hours, then 
remain in the 24-25 C range between 6 to 48 hours.  Vertical wind 
shear will remain low through 48 h, then steadily increase during 
the day 3 to 5 period as Linda approaches a potent upper-level 
trough located to the northwest of Oahu. Perhaps even more 
detrimental than the gradually increasing wind shear is the dry 
airmass that Linda is embedded in, with environmental mid-level 
relative humidity values of less than 40 percent. Mid-level moisture 
is forecast to decrease further over the next 48 hours. A 
combination of these environmental factors will ultimately lead to 
the loss of deep convection, and Linda is forecast to become a 
post-tropical gale by Saturday. Although the intensity forecast 
reasoning has not changed appreciably, a slightly faster weakening  
rate is forecast through the first 36 hours. However, the new NHC 
intensity forecast still lies at the high end of the guidance during 
that time. Beyond 36 h, little change has been made to the previous 
forecast.

The initial motion is 285/12 kt. A well-established subtropical 
ridge should steer Linda in a westward to west-northwestward fashion 
during the next 5 days. There is essentially no change to the 
forecast track through 72 hours. Thereafter, a slight southward 
nudge was made, but still lies just to the north of the TVCE and 
HCCA consensus aids. Linda is forecast to cross into the Central 
Pacific in about 30 h and is expected to pass to the north of the 
Hawaiian Islands as a post-tropical gale late Sunday into Monday.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  18/2100Z 18.7N 133.2W   85 KT 100 MPH
 12H  19/0600Z 19.3N 135.3W   75 KT  85 MPH
 24H  19/1800Z 20.0N 138.3W   65 KT  75 MPH
 36H  20/0600Z 20.6N 141.4W   55 KT  65 MPH
 48H  20/1800Z 21.0N 144.2W   50 KT  60 MPH
 60H  21/0600Z 21.3N 146.7W   45 KT  50 MPH
 72H  21/1800Z 21.8N 149.0W   40 KT  45 MPH...POST-TROPICAL
 96H  22/1800Z 22.7N 153.5W   35 KT  40 MPH...POST-TROPICAL
120H  23/1800Z 23.4N 158.5W   30 KT  35 MPH...POST-TROPICAL
 
$$
Forecaster Hagen/Papin/Cangialosi
 
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