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Hurricane MARIA


Hurricane Maria Discussion Number  12
NWS National Hurricane Center Miami FL       AL152017
1100 PM AST Mon Sep 18 2017

The Air Force Hurricane Hunters were able to fly a single pass
from northwest to southeast through the eye of Maria just prior to
0000 UTC.  The aircraft found a peak SFMR wind of 139 kt in the
northwest eyewall, i.e. category 5 intensity.  Raw objective
T-numbers from UW/CIMSS reached as high as T7.3 just before the
center moved over land.  Based on these data, the initial wind speed
was increased to 140 kt on the earlier special advisory, and that
intensity is maintained for this advisory, although some slight
weakening may have occurred as the small core of the hurricane
passed over Dominica.  Since the center has moved over land, the
aircraft has not been able to make a second pass through the eye.
The aircraft will be in the storm a few more hours and should be
able to provide additional center fixes once the eye moves west of

Maria is forecast to remain within an environment of low wind shear
and over warm water during the next couple of days.  Given these
favorable atmospheric and oceanic conditions, Maria is expected to
remain a Category 4 or 5 hurricane when it approaches the Virgin
Islands and Puerto Rico, however some fluctuations in intensity are
possible due during the next 24 to 36 h due to eyewall cycles.  Land
interaction and a slight increase in shear are likely to cause some
gradual weakening after Maria moves over the southwestern Atlantic
in 3 to 4 days.

Maria is moving west-northwestward or 300/8 kt.  A weak ridge
located over the western Atlantic is expected to steer the
hurricane west-northwestward through 48 hours, and on this track the
center of Maria is forecast to pass near or over the Virgin Islands
and Puerto Rico on Wednesday.  After that time, the western portion
of the ridge is forecast to weaken, which should allow Maria to turn
northwestward, then north-northwestward by day 5.  The track
guidance is in good agreement and little change was required to the
NHC track forecast through 72 hours.  At days 4 and 5, the global
model envelope has shifted slightly eastward and the NHC forecast
was adjusted accordingly to be in better agreement with the HFIP
correct consensus and ECMWF model.


1. Maria will affect portions of the Leeward Islands and the British
and U.S. Virgin Islands as an extremely dangerous major hurricane
during the next couple of days, and hurricane warnings are in effect
for many of these islands.

2. Maria is likely to affect Puerto Rico as an extremely dangerous
major hurricane, and a hurricane warning is in effect for that
island.  Preparations to protect life and property should be rushed
to completion.

3. The potential for a life-threatening storm surge, accompanied by
large and destructive waves, has increased for the Leeward Islands,
the Virgin Islands, and Puerto Rico.

4. Life-threatening flash floods and mudslides from heavy rainfall
are expected across the Leeward Islands, including Puerto Rico and
the U.S. and British Virgin Islands.


INIT  19/0300Z 15.5N  61.4W  140 KT 160 MPH
 12H  19/1200Z 16.1N  62.6W  140 KT 160 MPH
 24H  20/0000Z 17.0N  64.0W  140 KT 160 MPH
 36H  20/1200Z 17.9N  65.4W  135 KT 155 MPH
 48H  21/0000Z 18.7N  66.9W  125 KT 145 MPH
 72H  22/0000Z 20.5N  69.6W  120 KT 140 MPH
 96H  23/0000Z 22.8N  71.5W  110 KT 125 MPH
120H  24/0000Z 25.5N  72.5W  100 KT 115 MPH

Forecaster Brown