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Hurricane Fernanda Discussion Number  13
NWS National Hurricane Center Miami FL       EP072023
1100 AM HST Tue Aug 15 2023

Fernanda seems to be resuming a weakening trend possibly due to 
moderate deep-layer shear and embedded dry air. Infrared satellite 
images indicate that the coverage of deep convection has decreased 
during the past few hours. Subjective Dvorak estimates from SAB and 
TAFB remain at 77 kt and 102 kt, respectively. CIMSS ADT and AiDT 
estimates are in the 90 kt to 99 kt range. Thus, the initial 
intensity is decreased to 90 kt for this advisory.

The hurricane is now moving westward at 10 kt. The track forecast 
reasoning remains unchanged. A weak mid-level ridge to the northwest 
of Fernanda is expected to steer the cyclone generally westward over 
the next several days. The current NHC track forecast has been 
updated with minor adjustments.

The official forecast track takes Fernanda over cooler waters, 
crossing the 26C isotherm in 18 to 24 hours. While the current 
moderate vertical wind shear is expected to diminish in about 12 
hours, the hurricane will be encountering an increasingly dry and 
stable airmass. Therefore, Fernanda is forecast to quickly weaken 
over the next couple of days. Fernanda is now expected to become a 
post-tropical cyclone in 48 hours.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  15/2100Z 17.3N 122.8W   90 KT 105 MPH
 12H  16/0600Z 17.4N 124.6W   80 KT  90 MPH
 24H  16/1800Z 17.6N 127.2W   65 KT  75 MPH
 36H  17/0600Z 17.7N 129.9W   50 KT  60 MPH
 48H  17/1800Z 17.9N 132.8W   35 KT  40 MPH...POST-TROPICAL
 60H  18/0600Z 18.2N 135.8W   30 KT  35 MPH...POST-TROP/REMNT LOW
 72H  18/1800Z 18.4N 138.8W   30 KT  35 MPH...POST-TROP/REMNT LOW
 96H  19/1800Z 18.4N 144.9W   25 KT  30 MPH...POST-TROP/REMNT LOW
120H  20/1800Z 18.2N 150.5W   25 KT  30 MPH...POST-TROP/REMNT LOW
 
$$
Forecaster Delgado/Bucci
 
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