Hurricane Gilma Forecast Discussion

000
WTPZ42 KNHC 221452
TCDEP2

Hurricane Gilma Discussion Number  17
NWS National Hurricane Center Miami FL       EP072024
Issued by the NWS Weather Prediction Center College Park MD
500 AM HST Thu Aug 22 2024

Gilma has continued to intensify with recent tightening of the 
eyewall diameter in the last few hours. Concurrently, solid cooling 
was noted in the surrounding inner ring of convection.  This 
has resulted in an increase in intensity for the Dvorak intensity 
estimates with TAFB up to a T6.0/6.0 or 115 knots while 
objective estimates from UW-CIMSS has seen a variation of Raw-T 
values between 5.5 and 5.8.  As such, the intensity has been 
adjusted slightly upward to 110 knots and brings intensity up to 
a strong Category 3 hurricane on the Saffir-Simpson Scale. 

A northwest trend in center fixes continues to show slow forward 
speed at 290/6 knots, though small wobbles have been noted as the 
eye has been tightening and stronger convergence nodes are noted 
along the inner eye wall supporting a weak asymmetry to the eye 
itself.  Given weak mid-tropospheric forcing, storm motion will 
continue to be slow and is expected to turn more westward Friday 
into Saturday as it nears the 26-27C isotherm.  Proximity to the 
thermal gradient and convective activity will play a role in the 
longer term forecast as well.  Depending on the strength, a faster 
forward speed was noted through the guidance suite. As such, the 
official forecast is a bit faster along track though the track 
remains fairly stable.

Given that warmer oceans remain along the track of Gilma, some 
additional strengthening is expected with the low shear 
environment. As the cyclone reaches the 26-27C isotherm, gradual 
weakening is expected, but a slight northward adjustment will 
result in reduced warm, moist air to maintain its strength and 
slow weakening is expected after Friday morning.  As the storm 
treads further west, cooler water is likely to increase weakening of 
the system through the weekend into early next week.  As the system 
weakens and becomes shallower, forward speed will increase and 
perhaps further compound the weakening process a bit faster than 
prior forecast; however, the NHC intensity forecast 
remains on the higher end of the model guidance suite to better 
maintain continuity.


FORECAST POSITIONS AND MAX WINDS

INIT  22/1500Z 16.9N 124.5W  110 KT 125 MPH
 12H  23/0000Z 17.1N 125.4W  115 KT 130 MPH
 24H  23/1200Z 17.5N 126.8W  105 KT 120 MPH
 36H  24/0000Z 17.8N 128.3W  100 KT 115 MPH
 48H  24/1200Z 18.1N 129.9W   95 KT 110 MPH
 60H  25/0000Z 18.3N 131.5W   90 KT 105 MPH
 72H  25/1200Z 18.4N 133.3W   80 KT  90 MPH
 96H  26/1200Z 18.8N 137.1W   65 KT  75 MPH
120H  27/1200Z 19.1N 141.3W   55 KT  65 MPH

$$
Forecaster Gallina