Central Pacific Basin Tropical Cyclones

Tropical Storm Gilma Forecast Discussion



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WTPA42 PHFO 290849
TCDCP2

Tropical Storm Gilma Discussion Number  45
NWS Central Pacific Hurricane Center Honolulu HI   EP072024
1100 PM HST Wed Aug 28 2024

A few thunderstorms have been able to develop in association with 
Gilma's circulation this evening, but they have been unable to 
either wrap around, or move over, the center. This pulsing 
disorganized convection is doing little to sustain Gilma as a 
tropical cyclone, while also leading to lowering subjective and 
objective Dvorak intensity estimates that range from 1.5/25 kt to 
2.5/35 kt. The initial intensity estimate for this advisory is 
maintained at 35 kt, primarily based on a 0643Z ASCAT pass that 
showed maximum winds of 32 kt. 

Gilma's forward motion remains a steady 280/12 kt. A low-level 
ridge north of the cyclone will continue to steer it just north of 
due west over the next day or so, with a turn toward the 
west-northwest expected Friday as the ridge weakens. Little change 
to the previous forecast track was made, as consensus track guidance 
remains well clustered. 

Water vapor imagery and shear analyses indicate that Gilma is 
moving into an area of increasing westerly vertical wind shear on 
the order of 20-30 kt, associated with a trough aloft approaching 
from the west. GFS and ECMWF simulated satellite imagery indicate 
that Gilma will only produce brief periods of deep convection over 
the next day or two, with Gilma gradually spinning down from its 
peak that occurred just a few days ago. Gilma will likely become a 
post-tropical remnant low on Thursday, continue gradually weakening 
as it moves close to Hawaii on Friday, then dissipate in the 
vicinity of Kauai early Saturday.   


FORECAST POSITIONS AND MAX WINDS

INIT  29/0900Z 19.5N 149.5W   35 KT  40 MPH
 12H  29/1800Z 19.8N 151.3W   30 KT  35 MPH
 24H  30/0600Z 20.4N 153.6W   30 KT  35 MPH...POST-TROP/REMNT LOW
 36H  30/1800Z 21.2N 156.0W   25 KT  30 MPH...POST-TROP/REMNT LOW
 48H  31/0600Z 22.2N 158.3W   25 KT  30 MPH...POST-TROP/REMNT LOW
 60H  31/1800Z...DISSIPATED

$$
Forecaster Birchard



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