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Tropical Storm Maria Discussion Number   2
NWS National Hurricane Center Miami FL       AL152017
500 PM AST Sat Sep 16 2017

Satellite images indicate that the system located several hundred
miles east of the Lesser Antilles has become much better organized
throughout the day.  The low-level center of circulation is now
well defined, and banding features have become better established in
all quadrants.  The initial wind speed is increased to 45 kt, in
agreement with a Dvorak classification from TAFB.  This makes the
system a tropical storm, Maria becomes the thirteenth named storm
in the Atlantic basin this season.

Maria is moving quickly westward at 17 kt on the south side of a
mid-level ridge.  This ridge is expected to remain in place but
weaken some, which should cause Maria to move west-northwestward at
a progressively slower pace through the forecast period.  The
models are in fair agreement, and the NHC official track forecast
is closest to the HCCA model.  This forecast takes the core of
Maria near the Leeward Islands in 48 to 72 hours, and close to the
Virgin Islands and Puerto Rico in about 4 days.

The tropical storm is located within conducive environmental
conditions of low wind shear, high amounts of moisture, and over
warm 29 deg C SSTs.  Since these conditions are not expected to
change much, steady or even rapid strengthening is likely during the
next 3 to 4 days.  Slight weakening is predicted by the end of the
forecast period due to some land interaction and a slight increase
in wind shear.  The NHC intensity forecast is raised significantly
from the previous one to come into better agreement with the latest
guidance.

KEY MESSAGES:

1. Maria is expected to strengthen and affect portions of the
Leeward Islands as a hurricane early next week, bringing dangerous
wind, storm surge and rainfall hazards.  Hurricane and tropical
storm watches have been issued for portions of the Lesser Antilles,
and additional watches will likely be issued tonight and Sunday.

2. Maria could also affect the British and U.S. Virgin Islands and
Puerto Rico by mid week as a dangerous major hurricane, and
hurricane watches could be issued for these islands as early as
Sunday.  Interests in these areas should monitor the progress of
Maria and follow any advice given by local officials.

FORECAST POSITIONS AND MAX WINDS

INIT  16/2100Z 12.3N  52.6W   45 KT  50 MPH
 12H  17/0600Z 13.0N  54.5W   55 KT  65 MPH
 24H  17/1800Z 13.9N  56.6W   65 KT  75 MPH
 36H  18/0600Z 14.6N  58.3W   70 KT  80 MPH
 48H  18/1800Z 15.2N  59.8W   80 KT  90 MPH
 72H  19/1800Z 16.5N  62.7W   95 KT 110 MPH
 96H  20/1800Z 17.9N  65.5W  105 KT 120 MPH
120H  21/1800Z 19.5N  68.6W   95 KT 110 MPH

$$
Forecaster Cangialosi

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