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Hurricane Dorian Discussion Number 18
NWS National Hurricane Center Miami FL AL052019
500 PM AST Wed Aug 28 2019
The cloud pattern has become better organized with a hint of an eye
on high resolution satellite imagery and plenty of convective bands.
In addition, earlier data from a reconnaissance plane and surface
observations from St. Thomas as Dorian moved by yield an initial
intensity of 70 kt. Now that the hurricane has developed an inner
core with a 15 to 20 n mi eye, strengthening is more likely. Given
the favorable environment of warm waters and low shear prevailing in
the western Atlantic, the NHC forecast calls for a marked
intensification, and brings Dorian to category 3 intensity in 72
hours, and keeps it at that intensity until landfall. This
forecast is very close to the intensity consensus, the HCCA model,
and the SHIPS guidance.
Satellite and earlier reconnaissance plane fixes indicate that
Dorian has been moving toward the northwest or 320 degrees at 12
kt. The cyclone is heading toward a weakness in the Atlantic
subtropical ridge, and this northwest motion should continue for the
next 24 to 48 hours. However, after that time, all the global models
continue to build a strong ridge over the western Atlantic, and this
flow pattern should force Dorian to turn more to the west-northwest
toward Florida. All indications are that by this Labor Day weekend,
a powerful hurricane will be near or over the Florida peninsula. The
new NHC track forecast is a little bit to the south of the previous
one, given that global models have a stronger ridge to the north and
the track models show more of a westward motion. Users are reminded
not to focus on the exact forecast track, as the average 5-day track
error is around 200 miles.
Key Messages:
1. Dangerous winds will continue in the Virgin Islands, Culebra,
Vieques, and portions of Puerto Rico during the next few hours.
Heavy rainfall over portions of Puerto Rico and the Virgin Islands
could produce flash flooding through Thursday morning.
2. The risk of dangerous storm surge and hurricane-force winds later
this week and this weekend continues to increase in the central and
northwestern Bahamas and along the Florida east coast, although it
is too soon to determine where these hazards will occur. Residents
in these areas should ensure they have their hurricane plan in place
and not focus on the exact forecast track of Dorian's center.
3. Heavy rains are expected to occur over portions of the Bahamas,
Florida, and elsewhere in the southeastern United States later this
week and into early next week.
FORECAST POSITIONS AND MAX WINDS
INIT 28/2100Z 18.8N 65.5W 70 KT 80 MPH
12H 29/0600Z 20.1N 66.6W 75 KT 85 MPH
24H 29/1800Z 22.0N 68.0W 80 KT 90 MPH
36H 30/0600Z 23.8N 69.3W 85 KT 100 MPH
48H 30/1800Z 25.2N 71.1W 90 KT 105 MPH
72H 31/1800Z 26.8N 75.0W 100 KT 115 MPH
96H 01/1800Z 27.7N 79.0W 100 KT 115 MPH
120H 02/1800Z 28.2N 81.5W 85 KT 100 MPH...INLAND
$$
Forecaster Avila
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