Hurricane Gilma Forecast Discussion

751 
WTPZ42 KNHC 231434
TCDEP2

Hurricane Gilma Discussion Number  21
NWS National Hurricane Center Miami FL       EP072024
500 AM HST Fri Aug 23 2024

The cloud pattern associated with Gilma has lost some organization 
since the last advisory, with the eye become less distinct and the 
central dense overcast becoming more ragged.  The various objective 
and subjective satellite intensity estimates have trended downward 
during the past 6 h, and based on these data the initial intensity 
is decreased to 100 kt.

The westward jog mentioned in the previous advisory continues, with 
the initial motion now 275/7 kt.  A deep-layer trough north of Gilma 
near the west coast of the United States is expected to lift out 
over the next couple of days, which will allow a high pressure ridge 
to gradually build westward over the eastern North Pacific. As a 
result, Gilma should move generally west-northwestward to westward 
at a faster forward speed during the next several days. Due to the 
current westward jog, the guidance envelope has shifted a little to 
the south and west since the previous advisory.  Based on this 
guidance, the new track forecast, which lies close to the consensus 
models, will also shift a bit to the south.

Gilma is gradually moving toward cooler water, with the center 
expected to cross the 26C isotherm in about 36 h.  The hurricane is 
also moving into a drier and more stable air mass. This combination 
should lead to gradual weakening for the next 60 h or so.  Beyond 
that time, increasing shear and sea surface temperatures near 25C 
should cause a faster weakening rate, and Gilma is now expected to 
degenerate to a remnant low by 120 h.  The new intensity forecast 
follows the trend of the intensity guidance, but is nudged downward 
a little from the previous forecast.


FORECAST POSITIONS AND MAX WINDS

INIT  23/1500Z 17.4N 126.8W  100 KT 115 MPH
 12H  24/0000Z 17.6N 128.0W   95 KT 110 MPH
 24H  24/1200Z 18.0N 129.6W   90 KT 105 MPH
 36H  25/0000Z 18.3N 131.3W   85 KT 100 MPH
 48H  25/1200Z 18.6N 133.1W   75 KT  85 MPH
 60H  26/0000Z 18.9N 134.9W   70 KT  80 MPH
 72H  26/1200Z 19.2N 137.0W   60 KT  70 MPH
 96H  27/1200Z 19.9N 141.7W   45 KT  50 MPH
120H  28/1200Z 20.6N 147.0W   30 KT  35 MPH...POST-TROP/REMNT LOW

$$
Forecaster Beven