136
WTPA43 PHFO 111445
TCDCP3

Hurricane Henriette Discussion Number  30
NWS Central Pacific Hurricane Center Honolulu HI   EP082025
Issued by NWS National Hurricane Center Miami FL
500 AM HST Mon Aug 11 2025

Henriette has been going through some rapid structural changes
during the past several hours.  A 1138 UTC GMI microwave pass
confirmed that an eyewall replacement was in the process of
occurring, with a ring of deep convection surrounding a small
remnant of the previous eyewall.  Since that time, convection
appears to have redeveloped in the inner eyewall, and a small eye
is trying to form in conventional satellite imagery.  Dvorak CI
numbers at 1200 UTC from PHFO, SAB, and JTWC ranged between 4.0/65
kt and 4.5/77 kt, while most of the objective numbers are between
70-80 kt.  The initial intensity is raised to 75 kt as a blend of
all these numbers.

The hurricane is moving quickly toward the northwest, or 310/16 kt.
The forecast track is remarkably straight and steady during the next
48 hours or so, as Henriette is steered between a mid-level low
northwest of the Hawaiian Islands and a large ridge centered off the
coast of the Pacific Northwest United States.  After 48 hours, the
cyclone is expected to turn toward the north-northwest and slow down
when it reaches the western periphery of the ridge.  Confidence
remains high in the track forecast, and the new NHC prediction is
right on top of the previous one, lying close to the TVCE and HCCA
consensus aids.

Henriette probably has another 12-24 hours to take advantage of an
environment of sufficiently warm sea surface temperatures, low
shear, and upper-level divergence.  The NHC forecast therefore
shows a little more strengthening in the short term.  Although
ocean temperatures only become gradually cooler after that time,
the atmosphere quickly becomes less conducive with an increase in
shear and convergence aloft.  Weakening is therefore indicated, at
a rate similar to the bulk of the guidance, and Henriette could
become post-tropical in about 60 hours when it loses its organized
deep convection.  The post-tropical cyclone/remnant low is then
likely to dissipate by day 5 over the far northern Pacific.

FORECAST POSITIONS AND MAX WINDS

INIT  11/1500Z 28.8N 156.5W   75 KT  85 MPH
 12H  12/0000Z 30.4N 158.6W   80 KT  90 MPH
 24H  12/1200Z 32.5N 161.1W   75 KT  85 MPH
 36H  13/0000Z 34.5N 163.7W   70 KT  80 MPH
 48H  13/1200Z 36.5N 166.4W   50 KT  60 MPH
 60H  14/0000Z 38.5N 168.6W   40 KT  45 MPH...POST-TROPICAL
 72H  14/1200Z 40.4N 169.9W   30 KT  35 MPH...POST-TROP/REMNT LOW
 96H  15/1200Z 43.1N 171.1W   20 KT  25 MPH...POST-TROP/REMNT LOW
120H  16/1200Z...DISSIPATED

$$
Forecaster Berg