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Hurricane Dora Discussion Number 23
NWS National Hurricane Center Miami FL EP052023
500 PM HST Sat Aug 05 2023
Dora has acquired annular traits, highlighted by a circular and
relatively large eye (compared to the size of the hurricane itself),
a wide band of very cold cloud tops within the CDO, and dissolving
outer bands around the periphery of the circulation. As a
reflection of this, the Annular Hurricane Index (AHI) has increased
to about 85 out of 100. The maximum winds are now estimated to be
125 kt, which best matches a Dvorak estimate of T6.5/127 kt from SAB
and objective ADT and AiDT numbers of 123-125 kt.
There's no new news to report regarding Dora's forecast track. A
ridge building westward to the north of the hurricane is expected
to push Dora faster toward the west while it passes well south of
Hawaii in the next 2-4 days. The track guidance--and the NHC
official forecast--have been remarkably steady for the past few
days, and the new forecast is basically an update of the previous
prediction.
Fluctuations in intensity are possible during the next 6-12 hours
while Dora becomes increasingly annular. The hurricane is forecast
to continue moving nearly parallel to the sea surface temperature
gradient, over waters of 26-27C for the next several days.
Deep-layer shear is expected to remain light, although Dora is
likely to move into a drier, more subsident environment into early
next week. That said, annular hurricanes have a proclivity for
weakening more slowly than expected or suggested by intensity
models, and the new NHC forecast therefore lies near the upper
bound of the available guidance, showing only gradual weakening
through the 5-day forecast period. This forecast is closest to the
SHIPS guidance during the first couple of days, and then trends
close to the HCCA and IVCN consensus aids thereafter.
FORECAST POSITIONS AND MAX WINDS
INIT 06/0300Z 13.2N 136.5W 125 KT 145 MPH
12H 06/1200Z 13.0N 139.0W 125 KT 145 MPH
24H 07/0000Z 12.8N 142.7W 120 KT 140 MPH
36H 07/1200Z 12.5N 146.4W 110 KT 125 MPH
48H 08/0000Z 12.4N 150.2W 100 KT 115 MPH
60H 08/1200Z 12.3N 154.0W 95 KT 110 MPH
72H 09/0000Z 12.4N 157.7W 90 KT 105 MPH
96H 10/0000Z 12.9N 165.6W 80 KT 90 MPH
120H 11/0000Z 14.1N 173.1W 75 KT 85 MPH
$$
Forecaster Berg
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