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Hurricane Linda Discussion Number  37
NWS National Hurricane Center Miami FL       EP122021
1100 PM HST Wed Aug 18 2021
 
Linda is slowly losing convective organization with the eye now
open in the western quadrant in both infrared and passive microwave
satellite imagery. However, the upper-level cirrus outflow remains
quite impressive and nearly symmetrical. The initial intensity has 
been lowered to 75 kt based a blend of Dvorak satellite current 
intensity (CI) estimates of 65 kt from TAFB and 77 kt from SAB, and 
objective satellite intensity estimates of T4.3/72 kt and 77 kt 
from UW-CIMSS ADT and SATCON, respectively.
 
The initial motion estimate remains west-northwestward, or 285/15
kt. This general motion is forecast by the global and regional
models to continue throughout the forecast period as Linda moves
along the southern periphery of a strong deep-layer ridge anchored
across most of the eastern and central Pacific basins. The new NHC
forecast track is essentially just an update of the previous
advisory track and lies close to the middle of the tightly clustered
simple- and corrected-consensus track models. On the current track,
Linda should cross into the Central Pacific basin in about 18 hours.
 
Linda is located over 24-25 C sea-surface temperatures (SST), which
are expected to remain steady for the next 48-60 hours, during 
which the vertical wind shear is expected to remain low at around
5 kt. The favorable shear should help to offset the unfavorable
SSTs beneath the cyclone, resulting in a slower-than-normal rate
of weakening. Thereafter, SSTs are forecast to gradually increase
above 26 deg C on days 4 and 5. However, the vertical wind shear is
forecast to increase from the southwest in excess of 30 kt, causing
even greater weakening. The new official intensity forecast is
similar to the previous advisory and calls for Linda to steadily
weaken through the forecast period and degenerate into a 
post-tropical gale by 60 hours, which is in line with the trend in
the IVCN and HCCA intensity consensus models.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  19/0900Z 19.7N 136.2W   75 KT  85 MPH
 12H  19/1800Z 20.2N 138.5W   60 KT  70 MPH
 24H  20/0600Z 20.7N 141.6W   50 KT  60 MPH
 36H  20/1800Z 21.0N 144.5W   45 KT  50 MPH
 48H  21/0600Z 21.3N 147.0W   40 KT  45 MPH
 60H  21/1800Z 21.7N 149.4W   40 KT  45 MPH...POST-TROPICAL
 72H  22/0600Z 22.1N 151.6W   40 KT  45 MPH...POST-TROPICAL
 96H  23/0600Z 23.0N 156.2W   35 KT  40 MPH...POST-TROPICAL
120H  24/0600Z 23.6N 161.4W   25 KT  30 MPH...POST-TROP/REMNT LOW
 
$$
Forecaster Stewart
 
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