Central Pacific Basin Tropical Cyclones

Tropical Storm Gilma Forecast Discussion



047 
WTPA42 PHFO 281445
TCDCP2

Tropical Storm Gilma Discussion Number  42
NWS Central Pacific Hurricane Center Honolulu HI   EP072024
500 AM HST Wed Aug 28 2024

ProxyVis satellite imagery shows Gilma's exposed low-level 
circulation center tracking just north of due west. Limited 
deep convection is forming a weak curved band north and northeast 
of the center, where an earlier ASCAT pass detected winds near 40 
kt. This data, and a blend of the subjective Dvorak estimates from 
PHFO, JTWC and SAB, supports lowering the initial intensity estimate 
to 40 kt. 

The initial motion estimate is 280/12 kt. A low-level ridge north 
of Gilma will continue to steer the shallow cyclone westward to 
west-northwestward until it dissipates near Kauai this weekend. 
There has been little change in the track guidance, and the new 
forecast track is similar to the previous track, and lies close to 
HCCA and FSSE guidance.

Gilma is expected to gradually degenerate to a remnant low as it 
passes close to the Hawaiian Islands Friday into Saturday. Guidance 
indicates the strong westerly vertical wind shear currently 
impacting Gilma will briefly ease later today as a passing trough 
aloft lifts north, slowing the recent rapid weakening trend. Another 
trough aloft approaching from the west will bring even stronger 
vertical wind shear Thursday and Friday, eventually leading to 
dissipation. The new intensity forecast follows trends presented by 
the intensity consensus IVCN and SHIPS. 


FORECAST POSITIONS AND MAX WINDS

INIT  28/1500Z 18.8N 145.7W   40 KT  45 MPH
 12H  29/0000Z 19.1N 147.5W   40 KT  45 MPH
 24H  29/1200Z 19.6N 149.8W   35 KT  40 MPH
 36H  30/0000Z 20.1N 152.0W   35 KT  40 MPH
 48H  30/1200Z 20.7N 154.4W   30 KT  35 MPH...POST-TROP/REMNT LOW
 60H  31/0000Z 21.4N 156.8W   30 KT  35 MPH...POST-TROP/REMNT LOW
 72H  31/1200Z 22.3N 159.2W   25 KT  30 MPH...POST-TROP/REMNT LOW
 96H  01/1200Z...DISSIPATED

$$
Forecaster Birchard




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