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Hurricane Linda Discussion Number  32
NWS National Hurricane Center Miami FL       EP122021
500 PM HST Tue Aug 17 2021

Linda has made a bit of a comeback over the last 6-12 hours. While 
the eye continues to remain clear and warm, the eyewall convection 
has been gradually cooling over the course of the day, with a 
thickening ring of -60 to -65 C cloud top temperatures occasionally 
surrounding the eye. This has led to an increase in the most recent 
subjective Dvorak intensity estimates which at 0000 UTC were 
T5.5/102 kt from SAB and T5.0/90 kt from TAFB. The latest objective 
UW-CIMSS ADT estimate is up to T5.3/97 kt though the most recent 
SATCON estimate was only 79 kt. Taking a blend of these data yields 
an estimated intensity of 90 kt for this advisory.

Linda is starting to gain some latitude, with the estimated motion 
now at 280/10 kt. The track guidance philosophy remains the same, 
with a mid-level ridge well-established across the North Pacific 
expected to keep Linda moving on a west-northwestward track thorough 
the forecast period. Once again, the guidance has shifted a bit 
faster over the forecast period, and the latest NHC track forecast 
has also been nudged a little faster. Based on the latest forecast, 
Linda should be crossing into the Central Pacific in about 48 hours, 
and is expected to pass by to the north of the Hawaiian Islands as a 
post-tropical gale late in the weekend.

Linda's recent increase in intensity could be related to the cyclone 
moving over a small finger of warmer sea-surface temperatures (SSTs) 
currently. The storm has continued to maintain its stable annular 
structure, and little change in strength is expected during the next 
12 h. However, SSTs will soon begin to decrease once again and 
should drop below 25 C beyond 24 hours. While the deep-layer 
vertical wind shear diagnosed by SHIPS is expected to remain low for 
the next 72 hours, a bit more westerly mid-level shear could begin 
to undercut the outflow layer in 24-36 hours. For these reasons, 
Linda should begin a more pronounced weakening trend after 24 hours, 
with the tropical cyclone forecast to finally drop below hurricane 
intensity Thursday Night. The latest NHC intensity forecast remains 
on the high side of the guidance for the first 24 hours, but then is 
brought down to the guidance mean afterwards, in best agreement with 
the HFIP Corrected Consensus Approach (HCCA) guidance. While SSTs do 
begin to increase again after 72 hours, an increase in southwesterly 
shear is expected to prevent organized convection from redeveloping 
near the center, and Linda is forecast to become a post-tropical 
gale by that time.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  18/0300Z 17.9N 129.5W   90 KT 105 MPH
 12H  18/1200Z 18.4N 131.2W   90 KT 105 MPH
 24H  19/0000Z 19.2N 133.9W   80 KT  90 MPH
 36H  19/1200Z 20.0N 136.9W   70 KT  80 MPH
 48H  20/0000Z 20.7N 140.0W   60 KT  70 MPH
 60H  20/1200Z 21.3N 142.9W   50 KT  60 MPH
 72H  21/0000Z 21.6N 145.6W   40 KT  45 MPH...POST-TROPICAL
 96H  22/0000Z 22.2N 150.0W   35 KT  40 MPH...POST-TROPICAL
120H  23/0000Z 22.7N 154.2W   35 KT  40 MPH...POST-TROPICAL
 
$$
Forecaster Papin/Brown
 
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