Dorian could be a category 3 hurricane when it is expected to approach Florida
Satellite and radar images indicate that the cloud pattern has
become better organized during the past several hours. This was
confirmed by data from an Air Force reconnaissance plane currently
investigating Dorian, which reported a flight-level wind of 72 kt
and a peak SFMR value of 60 kt.  The estimated central pressure was
999 mb in the last fix.  On this basis the initial intensity has
been adjusted upward to 60 kt.  Only a slow strengthening is
anticipated today while Dorian is moving through the U.S. and
British Virgin Islands.  However, once the cyclone reaches the
western Atlantic well east of the Bahamas, it will encounter a
favorable environment of low shear and warm waters, resulting in a
more marked intensification. The NHC foreast is more aggressive than
the previous one, and brings Dorian to category 3 intensity by the
end of the period. This forecast very closely follows the intensity
consensus, the HCCA model, and the SHIPS guidance.

Fixes from the reconnaissance plane indicate that Dorian has been
moving toward the northwest or 315 degrees at 11 kt. The cyclone is
heading toward a weakness in the Atlantic subtropical ridge, and
this motion should continue for the next 2 to 3 days. However, after
that time, all global models build a robust ridge over the western
Atlantic, and this flow pattern should force Dorian to turn more
to the west-northwest toward Florida and the southeast coast of the
United States. All indications are that by this Labor Day weekend, a
powerful hurricane will be near the Florida or southeastern coast of
the United States. The new NHC track forecast is not significantly
different from the previous one, and it very closely follows the
multi-model consensus TVCA and the HCCA. 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. Hurricane conditions are expected in the U.S. and British Virgin
Islands, Culebra, and Vieques today. Tropical storm conditions are
expected in Puerto Rico today with hurricane conditions possible.

2. Heavy rainfall over portions of Puerto Rico and the U.S. and
British Virgin Islands could produce flash flooding during the next
couple of days.  Heavy rains are expected to occur over portions of
the Bahamas, Florida, and elsewhere in the southeastern Untied
States later this week and into early next week.

3. The risk of dangerous storm surge and hurricane-force winds is
increasing 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 that
they have their hurricane plan in place and not focus on the exact
forecast track of Dorian's center.