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Tropical Storm Hilda Discussion Number 23
NWS National Hurricane Center Miami FL EP082021
200 AM PDT Thu Aug 05 2021
Hilda is maintaining a small, but shrinking area of deep
convection, which has rotated from the southeast to northern portion
of the storm's circulation. A 0405 UTC ASCAT-A and 0522 UTC ASCAT-B
pass had peak wind retrievals of 36 and 40 kt respectively, about
40 n mi northeast of Hilda's center. This scatterometer data
suggests that the storm might have been stronger than estimated
yesterday when the convection was more robust. However, given the
warming cloud tops and shrinking area of convection since that time,
the initial advisory intensity was kept at 35 kt, which still agrees
with the most recent subjective Dvorak estimate from TAFB.
Hilda is moving to the west-northwest at 8 kt as the tropical
cyclone remains steered by a large subtropical ridge over the
eastern North Pacific. As the storm becomes more shallow, its
general motion should bend westward and gradually accelerate due to
the influence of a large low-level ridge centered well northward.
The latest track guidance is slightly more poleward early on, and
the NHC track forecast was nudged a bit further north, but remains a
bit south of the HFIP corrected consensus approach (HCCA). As noted
previously, the GFS model forecast remains a northern outlier, with
more interaction between Hilda and recently upgraded Jimena, and its
solution is not favored at this time.
As Hilda continues to move over increasingly cool ocean waters and
into a drier and more stable environment, the remaining deep
convection will likely dissipate at some point later today.
Additional convective bursts thereafter will become increasingly
unlikely. The latest NHC forecast expects Hilda to weaken to a
tropical depression later today and become a remnant low by
tomorrow. This solution is favored by most of the intensity
guidance. The remnant low is then forecast to open up into a trough
by the weekend, well east of the Hawaiian Islands.
FORECAST POSITIONS AND MAX WINDS
INIT 05/0900Z 20.1N 129.2W 35 KT 40 MPH
12H 05/1800Z 20.9N 130.7W 30 KT 35 MPH
24H 06/0600Z 21.9N 132.9W 30 KT 35 MPH
36H 06/1800Z 22.6N 135.1W 25 KT 30 MPH...POST-TROP/REMNT LOW
48H 07/0600Z 23.2N 137.3W 20 KT 25 MPH...POST-TROP/REMNT LOW