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Hurricane Gilma Discussion Number  34
NWS National Hurricane Center Miami FL       EP072024
500 AM HST Mon Aug 26 2024
 
Gilma still has a well-defined eye, seen on GOES-18 infrared and 
proxy-vis satellite imagery.  The latest subjective intensity 
estimates are T-4.5/77 kt from TAFB and T-5.0/90 kt from SAB. Recent 
objective intensity estimates from UW-CIMSS such as the ADT and 
DPRINT are in the 80 to 85 kt range.  However, during the last 
couple of hours, the eye has warmed and the cloud tops in the 
eyewall have cooled, so the initial intensity is increased to 90 kt, 
in best agreement with the SAB Dvorak intensity estimate.

Gilma is likely currently experiencing 10 to 15 kt of westerly wind 
shear as it continues moving near and parallel to the 26C SST 
isotherm.  Fluctuations in intensity appear possible for the next 12 
h.  Beyond 12 to 18 h, the westerly shear is forecast to increase to 
the 15 to 20 kt range, and the SSTs are forecast to decrease 
slightly along the path beyond 36 h.  These factors, along with the 
relatively dry, stable environmental air mass that Gilma will be 
traversing for the remainder of its lifetime, are expected to lead 
to continued steady weakening.  The NHC intensity forecast is a bit 
higher than the previous official forecast at hour 12, and then is 
similar to the previous official forecast.  The NHC forecast is near 
the middle of the intensity guidance envelope.
 
Gilma's initial motion is estimated to be westward, or 275/7 kt as
it continues moving along the southern periphery of a
mid-tropospheric subtropical ridge.  The models continue to be in
good cross-track agreement that the west to west-northwestward
motion will continue, although there are still some along-track
differences in the guidance.  The new NHC forecast lies very close
to, but perhaps a touch to the south of the previous official
forecast.  This forecast is close to the HCCA and TCVE consensus
aids.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  26/1500Z 18.2N 136.5W   90 KT 105 MPH
 12H  27/0000Z 18.3N 137.9W   85 KT 100 MPH
 24H  27/1200Z 18.5N 139.8W   70 KT  80 MPH
 36H  28/0000Z 18.7N 141.9W   60 KT  70 MPH
 48H  28/1200Z 19.0N 144.0W   55 KT  65 MPH
 60H  29/0000Z 19.5N 146.0W   45 KT  50 MPH
 72H  29/1200Z 19.9N 148.0W   40 KT  45 MPH
 96H  30/1200Z 20.8N 152.4W   30 KT  35 MPH...POST-TROP/REMNT LOW
120H  31/1200Z 21.8N 156.9W   25 KT  30 MPH...POST-TROP/REMNT LOW
 
$$
Forecaster Hagen/Pasch
 
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