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Tropical Storm ROSA


Tropical Storm Rosa Discussion Number   2
NWS National Hurricane Center Miami FL       EP202018
900 AM MDT Tue Sep 25 2018

The cloud pattern of the tropical cyclone has become better
organized, with developing convective banding features.  Dvorak
intensity estimates are 35 kt and 45 kt from SAB and TAFB,
respectively, and the current intensity estimate is set at 40 kt.
Thus the system is being upgraded to a tropical storm.  Conditions
favor continued strengthening, with Rosa likely to remain in an
environment of warm waters, low shear, and a very moist mid-level
air mass for the next several days.  The official intensity
forecast is a little higher than the previous one, but below some of
the objective guidance.  By late in the forecast period, a gradual
weakening trend should commence as the system begins to move over
slightly cooler waters.

The storm is moving west-northwestward, or 285/8 kt.  A mid-level
ridge is forecast by the global models to remain in place to the
north of Rosa through the middle part of the forecast period.  This
would likely maintain a generally west-northwestward motion for the
next 72 hours or so.  By days 4-5, the ridge is predicted to weaken
which should result in a gradual turn toward the northwest and
north-northwest.  The official track forecast is similar to that
from the previous advisory and is close to the corrected dynamical
model consensus, HCCA.


INIT  25/1500Z 14.7N 108.0W   40 KT  45 MPH
 12H  26/0000Z 15.2N 109.1W   50 KT  60 MPH
 24H  26/1200Z 15.8N 110.6W   60 KT  70 MPH
 36H  27/0000Z 16.1N 112.1W   70 KT  80 MPH
 48H  27/1200Z 16.4N 113.7W   80 KT  90 MPH
 72H  28/1200Z 17.1N 116.7W   95 KT 110 MPH
 96H  29/1200Z 18.8N 118.9W   90 KT 105 MPH
120H  30/1200Z 21.0N 120.0W   85 KT 100 MPH

Forecaster Pasch