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Tropical Storm Linda Discussion Number  41
NWS Central Pacific Hurricane Center Honolulu HI   EP122021
1100 PM HST Thu Aug 19 2021
 
The clock is ticking on Linda's time as a tropical cyclone. 
Infrared satellite imagery indicates a lack of deep convection over 
the last 12 to 18 hours, with some cooler cloud tops north of the 
low-level center being rapidly ushered away by strong upper-level 
winds. A well-timed 0528Z ASCAT pass was the primary reason for 
maintaining the initial intensity at 40 kt for this advisory, with 
these winds confined to the northern semicircle. 

The initial motion estimate is 270/15 kt, with Linda being steered 
by a low- to mid-level ridge to the north. The ridge will continue 
to steer the system westward, although some slowing in forward speed 
is expected Friday and Saturday. The updated track forecast has 
changed very little from the previous official forecast, but a 
slight southward nudge was made beyond 48 hours, in line with the 
latest, tightly-clustered guidance. 

Although Linda has rapidly weakened over the last day or so, a much 
slower rate of weakening is expected over the next couple of days, 
even as Linda becomes post-tropical. This is supported by global 
model guidance, as well as the intensity consensus IVCN, which 
indicate a gradual spin-down of the low-level cloud swirl, with gale 
force winds persisting in the northern semicircle for a couple more 
days. The combined effects of cool SSTs, dry air in the mid- and 
upper-levels, and strong vertical wind shear will lead to system 
dissipation by day 5.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  20/0900Z 19.9N 142.5W   40 KT  45 MPH
 12H  20/1800Z 20.3N 144.8W   35 KT  40 MPH...POST-TROPICAL
 24H  21/0600Z 20.5N 147.4W   35 KT  40 MPH...POST-TROPICAL
 36H  21/1800Z 20.9N 149.6W   35 KT  40 MPH...POST-TROPICAL
 48H  22/0600Z 21.1N 151.7W   35 KT  40 MPH...POST-TROPICAL
 60H  22/1800Z 21.4N 153.9W   30 KT  35 MPH...POST-TROP/REMNT LOW
 72H  23/0600Z 21.4N 156.1W   30 KT  35 MPH...POST-TROP/REMNT LOW
 96H  24/0600Z 21.5N 161.2W   25 KT  30 MPH...POST-TROP/REMNT LOW
120H  25/0600Z...DISSIPATED
 
$$
Forecaster Birchard
 
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