Tropical Storm Gilma Forecast Discussion

057 
WTPZ42 KNHC 200237
TCDEP2

Tropical Storm Gilma Discussion Number   7
NWS National Hurricane Center Miami FL       EP072024
800 PM PDT Mon Aug 19 2024

Gilma is looking a little more ragged on satellite imagery this 
evening.  Deep convection is confined to the southwest quadrant of 
the circulation and the cloud top temperatures have been gradually 
warming.  Still, subjective Dvorak estimates from TAFB and SAB have 
held steady this cycle, partially due to constraints.  The initial 
intensity remains at a possibly generous 50 kt.

The storm is moving westward at an estimated 9 kt.  The track 
reasoning has not changed.  A mid-level ridge centered over the 
southwestern United States is expected to turn Gilma  
west-northwestward soon and steer the storm in this general 
direction for the entirety of the forecast period.  The forward 
motion of the storm should slow in the next day or so as a 
deep-layer trough off of the U.S. west coast weakens the ridge.  
There is still quite a bit of spread in the model track guidance, 
though the envelope has shifted southward this cycle.  The official 
forecast has been nudged slightly south of the previously predicted 
track and remains near the various consensus aids.

The strong-to-moderate vertical wind shear is expected to abate 
within a day or so according to the global models.  Once this 
occurs, oceanic and environmental conditions should allow for steady 
strengthening, and Gilma is forecast to reach hurricane strength 
late this week or early this weekend.  There is a wide range in the 
intensity model guidance, making this forecast somewhat uncertain.  
The latest official intensity forecast is very similar to the 
previous prediction and lies in the middle of the guidance envelope.


FORECAST POSITIONS AND MAX WINDS

INIT  20/0300Z 15.2N 117.3W   50 KT  60 MPH
 12H  20/1200Z 15.6N 118.7W   55 KT  65 MPH
 24H  21/0000Z 16.1N 120.5W   55 KT  65 MPH
 36H  21/1200Z 16.6N 122.3W   55 KT  65 MPH
 48H  22/0000Z 17.1N 123.7W   60 KT  70 MPH
 60H  22/1200Z 17.6N 124.9W   70 KT  80 MPH
 72H  23/0000Z 18.0N 125.9W   75 KT  85 MPH
 96H  24/0000Z 18.8N 128.0W   75 KT  85 MPH
120H  25/0000Z 19.6N 130.2W   60 KT  70 MPH

$$
Forecaster Bucci