Hurricane Gilma Forecast Discussion

596 
WTPZ42 KNHC 252043
TCDEP2

Hurricane Gilma Discussion Number  31
NWS National Hurricane Center Miami FL       EP072024
1100 AM HST Sun Aug 25 2024

GOES-18 satellite images indicate that Gilma's eye continues to 
become more cloud-filled and less well-defined.  Microwave images 
from earlier this morning showed a better-defined eye at that time.  
The latest subjective intensity estimates from TAFB and SAB are 
T-5.5/102 kt.  The UW-CIMSS objective intensity estimates have also 
decreased from 6 hours ago, and range from about 77 to 104 kt.  The 
initial intensity has been lowered to 100 kt for this advisory, 
based on a blend of the data.

A combination of dry environmental air and marginal SSTs are likely 
the reasons why Gilma has weakened some today.  Gilma should 
continue to move over SSTs near or just above 26C for another 24 h 
before it reaches slightly cooler waters.  Gilma is still located 
within an environment of low vertical wind shear but is forecast to 
move into 15 kt of westerly vertical wind shear by early Monday 
which is expected to cause the storm to weaken.  The new NHC 
intensity forecast is similar to the previous forecast and 
is very near the intensity consensus aids.  The forecast shows 
steady weakening by about 15 kt per day.  By day 4, Gilma should 
move into an area of moderate to strong west-southwesterly vertical 
wind shear, which should strip away any remaining convection.  
Therefore, the forecast calls for Gilma to become a remnant low by 
day 5.

Gilma has been moving due west over the past 12 h, or 270/9 kt.  A 
mid-tropospheric ridge should continue to steer Gilma between west 
and west-northwest for the next several days.  The NHC track 
forecast is nearly on top of the previous prediction and is close 
to a blend of the HCCA and TVCE consensus aids through 72 h.  The 
NHC forecast is slightly south of those consensus aids beyond 72 h.


FORECAST POSITIONS AND MAX WINDS

INIT  25/2100Z 18.0N 134.3W  100 KT 115 MPH
 12H  26/0600Z 18.1N 135.7W   90 KT 105 MPH
 24H  26/1800Z 18.3N 137.4W   85 KT 100 MPH
 36H  27/0600Z 18.5N 139.1W   75 KT  85 MPH
 48H  27/1800Z 18.7N 140.9W   70 KT  80 MPH
 60H  28/0600Z 19.0N 142.7W   60 KT  70 MPH
 72H  28/1800Z 19.4N 144.5W   55 KT  65 MPH
 96H  29/1800Z 20.0N 147.9W   40 KT  45 MPH
120H  30/1800Z 20.6N 152.0W   30 KT  35 MPH...POST-TROP/REMNT LOW

$$
Forecaster Hagen/Pasch