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Tropical Storm Irwin Discussion Number  30
NWS National Hurricane Center Miami FL       EP102017
200 PM PDT Sat Jul 29 2017

Irwin's cloud pattern continues to be defined by a low-level center
located just to the north of a cyclonically curved convective band
in the southern semicircle. Dvorak intensity estimates are beginning
to indicate weakening, and a recent partial ASCAT pass shows maximum
winds of 40 kt. However, given the banding-type eye structure
observed on visible images, the initial intensity is kept at 50 kt.
The circulation is still over warm waters, and Irwin could maintain
the same intensity for another 12 hours or so. After that time, the
cyclone will begin to move over cooler waters resulting in gradual
weakening. Models are now showing that Irwin and Hilary will get
very close to each other while dissipating. Irwin is forecast to
become a remnant low by 72 hours and is expected to be dissipated by
day 5.

Irwin began to move toward the north or 360 degrees at 6 kt. Soon
the cyclone will be steered by the flow in the wake of Hilary and
turn more to the north-northwest and northwest with increasing
forward speed.  There is no significant change from the previous
forecast which continues to be very close to the multi-model
consensus primarily during the next 3 days.


FORECAST POSITIONS AND MAX WINDS

INIT  29/2100Z 15.6N 124.5W   50 KT  60 MPH
 12H  30/0600Z 16.7N 124.7W   50 KT  60 MPH
 24H  30/1800Z 18.7N 125.3W   45 KT  50 MPH
 36H  31/0600Z 21.0N 126.5W   40 KT  45 MPH
 48H  31/1800Z 23.5N 128.0W   30 KT  35 MPH
 72H  01/1800Z 26.5N 131.5W   25 KT  30 MPH...POST-TROP/REMNT LOW
 96H  02/1800Z 27.5N 134.0W   20 KT  25 MPH...POST-TROP/REMNT LOW
120H  03/1800Z...DISSIPATED

$$
Forecaster Avila

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