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Hurricane Marie Discussion Number 7
NWS National Hurricane Center Miami FL EP182020
200 PM PDT Wed Sep 30 2020
Marie has continued to become better organized today, with a
well-defined convective band that wraps more than completely around
the cloud system center. This yields a Dvorak intensity estimate of
at least 65 kt, and subjective and objective T-numbers from SAB and
UW-CIMSS respectively also correspond to an intensity of 65 kt.
Therefore, the system is being upgraded to a hurricane, which is the
first for the month of September in this relatively quiet eastern
North Pacific hurricane season. The vertical wind shear has
decreased and is forecast to remain low for the next few days.
This, combined with a moist low- to mid-tropospheric air mass and
warm sea surface temperatures, should lead to an environment that is
very conducive for strengthening. In fact, the SHIPS RI Index shows
a significant probability of rapid intensification over the next 24
hours. Therefore, the official forecast calls for Marie to become a
major hurricane tomorrow with additional strengthening during the
succeeding day. This is close to the predictions from the two
corrected consensus techniques, HCCA and FSSE. By 72 hours, Marie
should have begun passing over progressively cooler waters, so a
steady weakening trend is likely to be underway by that time.
The motion continues just north of due west, or 275/14 kt. The
track forecast reasoning hasn't changed much from the previous
advisories. Over the next few days, the hurricane should be steered
on a westward to west-northwestward course on the south side of a
mid-level subtropical ridge. Right around the end of the forecast
period, Marie should begin to turn more to the right in response to
a weakness in the ridge. The official track forecast is similar to
the previous one and lies between the simple and corrected dynamical
consensus predictions.
FORECAST POSITIONS AND MAX WINDS
INIT 30/2100Z 14.3N 115.1W 65 KT 75 MPH
12H 01/0600Z 14.4N 117.3W 85 KT 100 MPH
24H 01/1800Z 14.8N 120.0W 100 KT 115 MPH
36H 02/0600Z 15.6N 122.5W 115 KT 130 MPH
48H 02/1800Z 16.6N 124.7W 120 KT 140 MPH
60H 03/0600Z 17.7N 126.7W 120 KT 140 MPH
72H 03/1800Z 18.6N 128.4W 100 KT 115 MPH
96H 04/1800Z 20.3N 131.4W 70 KT 80 MPH
120H 05/1800Z 21.8N 134.0W 50 KT 60 MPH
$$
Forecaster Pasch
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