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Hurricane Dorian Discussion Number  28
NWS National Hurricane Center Miami FL       AL052019
500 AM EDT Sat Aug 31 2019

Dorian continues to look impressive in satellite imagery this
morning, with a fairly symmetric area of cold cloud tops surrounding
a 10-15 n mi wide eye.  There have been no new aircraft data from
the storm since the last advisory.  However, the satellite
appearance has changed little since the aircraft were last in the
storm, and the various subjective and objective satellite intensity
estimates have changed little over the past several hours.  Based on
this, the initial intensity remains 120 kt.

The initial motion is now 290/10.  A low- to mid-level subtropical
ridge to the north of the hurricane should steer it west-
northwestward to westward for the next 48 h or so, with the forward
speed becoming very slow as the center passes near or over the
Abacos and Grand Bahama. The track guidance for this part of the
track is tightly clustered, and the new forecast track is near the
ECMWF, UKMET, and HCCA corrected consensus models.  The track
forecast becomes much more problematic after 48 h.  The global
models the NHC normally uses, along with the regional HWRF and HMON
models, have made another shift to the east to the point where none
of them forecast Dorian to make landfall in Florida.  However, the
UKMET ensemble mean still brings the hurricane over the Florida
peninsula, as do several GFS and ECMWF ensemble members.  The new
track forecast for 72-120 h will be moved eastward to stay east of
the coast of Florida, and it lies between the old forecast and the
various consensus models.  Additional adjustments to the forecast
track may be necessary later today if current model trends continue.
It should be noted that the new forecast track does not preclude
Dorian making landfall on the Florida coast, as large portions of
the coast remain in the track cone of uncertainty.  Also,
significant impacts could occur even if the center stays offshore.

Dorian should remain in a generally favorable environment for the
next 3-4 days, and the intensity guidance indicates it will remain
a powerful hurricane during this time.  The new intensity forecast
calls for a little more strengthening today, then it shows a slow
weakening that follows the trend of the intensity guidance.  During
this time, the biggest intensity changes may come from hard-to-
forecast eyewall replacement cycles.  Late in the forecast period,
increased vertical shear and proximity to land is expected to
cause some weakening.


Key Messages:

1. A prolonged period of life-threatening storm surge and
devastating hurricane-force winds are likely in portions of the
northwestern Bahamas, particularly on the Abaco Islands and Grand
Bahama Island.  A hurricane warning is in effect for these areas,
and residents should listen to advice given by local emergency
officials and have their hurricane preparations completed today.

2. Life-threatening storm surge and devastating hurricane-force
winds are still possible along portions of the Florida east coast
by the early to middle part of next week, but since Dorian is
forecast to slow down and turn northward near the coast, it is too
soon to determine when or where the highest surge and winds will
occur. Residents should have their hurricane plan in place, know
if they are in a hurricane evacuation zone, and listen to advice
given by local emergency officials.

3. The risk of strong winds and life-threatening storm surge is
increasing along the coasts of Georgia and South Carolina during
the middle of next week.  Residents in those areas should continue
to monitor the progress of Dorian.

4. Heavy rains, capable of life-threatening flash floods, are
expected over portions of the Bahamas and coastal sections of the
southeastern United States this weekend through much of next week.


FORECAST POSITIONS AND MAX WINDS

INIT  31/0900Z 25.8N  72.6W  120 KT 140 MPH
 12H  31/1800Z 26.1N  74.0W  125 KT 145 MPH
 24H  01/0600Z 26.5N  75.8W  125 KT 145 MPH
 36H  01/1800Z 26.7N  77.2W  125 KT 145 MPH
 48H  02/0600Z 26.9N  78.1W  120 KT 140 MPH
 72H  03/0600Z 27.5N  79.4W  115 KT 130 MPH
 96H  04/0600Z 29.5N  80.5W  110 KT 125 MPH
120H  05/0600Z 32.0N  80.5W   95 KT 110 MPH

$$
Forecaster Beven

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