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Hurricane Maria Discussion Number  24
NWS National Hurricane Center Miami FL       AL152017
1100 PM EDT Thu Sep 21 2017

Satellite images show that the eye has become more distinct and is
surrounded by a ring of deep convection. An Air Force Hurricane
Hunter plane has penetrated the eye a couple of times this evening
and the crew reported that the eye had a diameter of 35 nmi and that
it has become better defined. Flight-level winds increased a little
bit during the last penetration and supported an intensity of 110 or
115 kt. At this time, I prefer the keep the winds at 110 kt since
the SFMR measurements were a little lower.  The central pressure is
estimated at 955 mb.

The atmosphere diagnosed by the models, as well as a warm ocean
along the forecast track, should favor an increase in intensity.
However, most of the models, suggest that Maria will change little
and will remain a category 3 hurricane for the next day or two. The
NHC forecast follows the intensity consensus ICON and shows no
significant change through that time. Gradual weakening should
begin later in the forecast period as Maria reaches higher latitudes
and cooler waters.

Satellite and reconnaissance fixes indicate that Maria is moving
toward the northwest or 320 degrees at 7 kt. The track of the
hurricane has been and will be controlled by the flow around a
narrow subtropical ridge to the northeast of the hurricane. Maria is
reaching the western edge of that high, and this should cause the
hurricane to turn north-northwestward and then northward with no
significant change in forward speed for the next 3 days. After that
time, Maria should encounter the mid-latitude southwesterly flow and
recurve. The reliable guidance is remarkably clustered during the
next 4 days. This significantly increases the confidence in the
track forecast which is in between the multi-model consensus TVCX
and the HFIP corrected consensus.


KEY MESSAGES:

1. Flash flood warnings continue in portions of Puerto Rico due
to persistent heavy rainfall from Maria's trailing rainbands.
Everyone in Puerto Rico should continue to follow advice from local
officials to avoid these life-threatening flooding conditions.

2. Swells from Maria are expected to begin reaching the coast of
the southeastern United States on Friday.  These swells are likely
to cause dangerous surf and life-threatening rip currents along the
coast for the next several days, even with Maria forecast to remain
well offshore over the western Atlantic Ocean.


FORECAST POSITIONS AND MAX WINDS

INIT  22/0300Z 21.0N  70.2W  110 KT 125 MPH
 12H  22/1200Z 22.0N  70.8W  110 KT 125 MPH
 24H  23/0000Z 23.5N  71.5W  105 KT 120 MPH
 36H  23/1200Z 25.1N  72.0W  100 KT 115 MPH
 48H  24/0000Z 26.7N  72.3W   95 KT 110 MPH
 72H  25/0000Z 29.3N  72.1W   90 KT 105 MPH
 96H  26/0000Z 31.2N  71.0W   85 KT 100 MPH
120H  27/0000Z 33.0N  70.0W   75 KT  85 MPH

$$
Forecaster Avila

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