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Tropical Depression One-C Discussion Number   1
NWS Central Pacific Hurricane Center Honolulu HI   CP012024
500 AM HST Thu Aug 22 2024

The area of low pressure well east-southeast of the Hawaiian Islands 
has become better organized overnight, with persistent deep 
convection now over the low-level circulation center. As a result, 
the first Tropical Depression of the season has formed in the 
Central Pacific basin. Subjective Dvorak intensity estimates came in 
at 2.5 PHFO and 1.5 SAB. Taking a blend of these estimates, the 
initial intensity will be set at 30 knots. 

The initial motion of Tropical Depression One is set at 270/12 
knots. This general motion is expected to continue during the next 
several days as the system is steered by a large subtropical ridge 
to the north. A decrease in forward speed and a slight turn toward 
the west- northwest is forecast by days 4 and 5 as a weakness 
develops in the subtropical ridge to the north. The track forecast 
is closely aligned with the consensus guidance. 

Tropical Depression One is forecast to remain in a low to moderate 
vertical wind shear environment, with warm sea surface temperatures 
of 27 to 28C, and adequate deep layer moisture during the next 
several days. This should result in gradual strengthening of the 
system as it tracks steadily westward, and a tropical storm will 
likely form later today. By late in the weekend into early next 
week, the tropical cyclone will begin to see an increase in westerly 
vertical wind shear and the potential for some entrainment of drier 
mid-level air. This should lead to a gradual weakening of the 
system. The intensity forecast is close to the intensity consensus 
during the next several days, bringing the system up close to 
hurricane strength over the weekend, then is slightly lower than the 
consensus guidance by days 4 and 5.  

KEY MESSAGES:

1. Tropical Depression One is forecast to approach the Hawaiian 
Islands during the next few days, bringing the potential for heavy 
rainfall, along with dangerous surf and rip currents. A Tropical 
Storm Watch could be required for portions of the main Hawaiian 
Islands tonight or Friday. 

 
FORECAST POSITIONS AND MAX WINDS
 
INIT  22/1500Z 15.4N 140.8W   30 KT  35 MPH
 12H  23/0000Z 15.6N 142.6W   35 KT  40 MPH
 24H  23/1200Z 15.8N 145.0W   40 KT  45 MPH
 36H  24/0000Z 16.0N 147.5W   45 KT  50 MPH
 48H  24/1200Z 16.2N 150.1W   55 KT  65 MPH
 60H  25/0000Z 16.6N 152.6W   60 KT  70 MPH
 72H  25/1200Z 16.8N 154.8W   60 KT  70 MPH
 96H  26/1200Z 17.3N 158.0W   60 KT  70 MPH
120H  27/1200Z 18.4N 161.3W   50 KT  60 MPH
 
$$
Forecaster Jelsema
 
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