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Hurricane Maria Discussion Number  41
NWS National Hurricane Center Miami FL       AL152017
500 AM EDT Tue Sep 26 2017

Maria is feeling the effects of the cool sea surface temperatures
left in the wake of Hurricane Jose.  Satellite imagery shows that
the convective pattern is gradually losing organization, with the
remaining convection in a cluster to the southeast of the center
and in bands well to the east of the center.  In addition, the
aircraft-reported central pressure has risen to 970 mb.  While there
have been no observations of hurricane-force winds from the Stepped
Frequency Microwave Radiometer on the NOAA Hurricane Hunter
currently in the cyclone, it is likely that they still exist in
areas east of the center where the airplane has not yet sampled.
The initial intensity is lowered to a somewhat uncertain 65 kt based
mainly on the rising central pressure since the last advisory.

The combination of the cool water and moderate shear should cause
Maria to gradually weaken during the forecast period, with the
system now expected to weaken to a tropical storm in less than 24 h.
Near the 120 h point, the cyclone is expected to merge with a
frontal system and become extratropical.  The new intensity forecast
is an update of the previous advisory.

The initial motion remains 360/6, with Maria moving northward on the
western side of the subtropical ridge.  A mid- to upper-level ridge
over the northeastern United States to the north of the cyclone is
likely to keep the motion slow for the next 36-48 h.  After that,
the mid-latitude westerlies are forecast to move southward across
the northeastern United States and break down the subtropical
ridge.  This should lead to Maria turning east-northeastward and
accelerating after 48 h.  The track guidance is in good agreement
with this scenario, and the new forecast track is close to the
previous track until 120 h, where it is nudged a bit to the south.
The track is also close to the center of the guidance envelope.


KEY MESSAGES:

1. Maria is forecast to continue moving northward, paralleling the
U.S. east coast for the next 36-48 hours, and it is likely that some
direct impacts will occur along portions of the North Carolina coast
beginning later today, where a Tropical Storm Warning is in effect.

2. Storm surge flooding, especially along the sound side of the
North Carolina Outer Banks, is expected beginning later today, and a
Storm Surge Watch has been issued for portions of eastern North
Carolina.

3. Swells generated by Maria are affecting much of the east coast of
the United States from Florida through southern New England.  These
swells are also affecting Bermuda, Puerto Rico, the northern coast
of Hispaniola, the Turks and Caicos Islands, and the Bahamas.  These
swells are likely to cause life-threatening surf and rip current
conditions.  Please consult products from your local weather office
for more information.


FORECAST POSITIONS AND MAX WINDS

INIT  26/0900Z 32.9N  73.1W   65 KT  75 MPH
 12H  26/1800Z 33.7N  73.2W   65 KT  75 MPH
 24H  27/0600Z 34.6N  73.1W   60 KT  70 MPH
 36H  27/1800Z 35.4N  72.7W   60 KT  70 MPH
 48H  28/0600Z 35.8N  71.7W   55 KT  65 MPH
 72H  29/0600Z 37.0N  66.0W   55 KT  65 MPH
 96H  30/0600Z 41.0N  53.0W   55 KT  65 MPH
120H  01/0600Z 48.0N  35.5W   55 KT  65 MPH...POST-TROP/EXTRATROP

$$
Forecaster Beven

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