Tropical Storm Hilda Discussion Number 4
NWS National Hurricane Center Miami FL EP082021
800 AM PDT Sat Jul 31 2021
Hilda is strengthening quickly this morning. Satellite images show
an eye feature trying to form, and convection has deepened and
become increasingly symmetric around the center. The latest Dvorak
estimates supported raising the initial intensity to 55 kt at 12Z,
and since Hilda continues to organize, the initial intensity is set
a little higher at 60 kt for this advisory. This makes Hilda just
below hurricane strength.
The current favorable environmental conditions of low wind shear,
high amounts of moisture, and warm SSTs should continue to allow
Hilda to intensify during the next day or so. In addition, given
that Hilda now has a tight inner core, rapid intensification (RI) is
a decent possibility, and the SHIPS RI index now shows a 30 percent
chance of that occurring during the next 24 hours. In a couple of
days, however, decreasing moisture and progressively cooler SSTs
should end the strengthening trend and gradually cause weakening
during the remainder of the forecast period. The NHC intensity
forecast is above than the previous one in the short term and it
lies at the high end of the model guidance. The long term forecast
is largely similar to the previous one and lies near the middle of
the guidance envelope.
Hilda is moving west-northwestward at 11 kt. A subtropical ridge
should keep the storm on a general west-northwest heading during the
next several days, but there could be some interaction with Tropical
Depression Nine-E to the west and a low pressure area to the east
that could cause slow downs and wobbles in the future track. There
is a fair amount of spread among the models, especially at the
longer range forecast times, but the latest consensus models are
right on top of the previous track. Therefore, the NHC track
forecast is largely just an update of the previous one.
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