Hurricane Dorian (Category Two) moves North Update One
WTNT45 KNHC 040256
TCDAT5
Hurricane Dorian Discussion Number 43
NWS National Hurricane Center Miami FL AL052019
1100 PM EDT Tue Sep 03 2019
Dorian's structure has changed significantly during the past day or
so. Satellite and Doppler radar images show that the inner core has
become rather broad with a large ragged eye of at least 30 n mi
diameter. Data from the Air Force Hurricane Hunters indicate
that the maximum winds and minimum pressure have held steady since
this afternoon, and based on that information, the initial
intensity is held at 95 kt, but this could be a little generous.
The aircraft data and surface observations indicate that the wind
field is expanding in size with tropical-storm-force and
hurricane-force winds extending up to 150 n mi and 50 n mi from the
center, respectively. NOAA data buoy 41010 just northeast of the
center has been reporting sustained winds as high as 60 kt with
gusts to 78 kt, and seas over 30 ft.
Dorian is finally on the move again, and the latest initial motion
estimate is 340 degrees at 5 kt. Dorian is being steered by the
flow between a mid-level ridge to the east and broad troughing to
its north. A northwest to north motion with some increase in
forward speed is expected through Wednesday, taking the core of
Dorian just offshore and parallel to the east coast of Florida
during that time. Thereafter, a faster motion toward the northeast
is predicted as a series of shortwave troughs move across the
northeastern U.S. This should take the core of the hurricane
very near, or possibly over, the coasts of South and North Carolina
on Thursday and Friday. After it passes the Outer Banks, the
hurricane is forecast to accelerate northeastward in the stronger
mid-latitude flow toward the Canadian Maritimes this weekend.
The NHC track forecast is largely unchanged and near the middle of
the tightly packed guidance envelope.
The hurricane is in a favorable environment of low wind shear, high
moisture, and warm SSTs, and it is expected to stay in these
conditions until it nears the Carolina coast. Therefore, Dorian is
expected to remain about the same intensity during the next couple
of days. After that time, an increase in shear from the
mid-latitude trough and drier air should cause Dorian to slowly
weaken. The GFS and ECMWF models both show Dorian becoming an
extratropical system by 96 hours, and the official forecast follows
those solutions. As this system gains latitude, the wind field is
expected to expand even more. Therefore, even if Dorian does not
make landfall, hurricane-force winds are expected to reach portions
of the coast from central Florida to North Carolina.
Key Messages:
1. Life-threatening storm surge and dangerous winds are expected
along portions of the Florida east coast and the coasts of Georgia,
South Carolina, and North Carolina, regardless of the exact track of
Dorian's center. Water levels could rise well in advance of the
arrival of strong winds. Residents in these areas should follow
advice given by local emergency officials.
2. The risk of wind and rain impacts along portions of the Virginia
coast and the southern Chesapeake Bay are increasing. Residents in
these areas should continue to monitor the progress of Dorian.
3. The flash flood threat will increase overnight along the Florida
east coast, then spread up the southeast and mid Atlantic coast
beginning Wednesday. There is a moderate risk of flash flooding
from coastal Georgia through the eastern portions of South and North
Carolina Wednesday and Thursday.
FORECAST POSITIONS AND MAX WINDS
INIT 04/0300Z 28.4N 79.0W 95 KT 110 MPH
12H 04/1200Z 29.4N 79.6W 95 KT 110 MPH
24H 05/0000Z 30.7N 79.9W 95 KT 110 MPH
36H 05/1200Z 31.9N 79.5W 95 KT 110 MPH
48H 06/0000Z 33.3N 78.2W 90 KT 105 MPH
72H 07/0000Z 37.1N 72.1W 75 KT 85 MPH
96H 08/0000Z 43.3N 62.7W 70 KT 80 MPH...POST-TROP/EXTRATROP
120H 09/0000Z 51.5N 52.2W 60 KT 70 MPH...POST-TROP/EXTRATROP
$$
Forecaster Cangialosi
FXUS61 KCAR 040147
AFDCAR
Area Forecast Discussion
National Weather Service Caribou ME
947 PM EDT Tue Sep 3 2019
.SYNOPSIS...
High pressure will exit across the Maritimes overnight. A cold
front will cross the region Wednesday. High pressure will build
across the area Thursday into Friday. Dorian will track south of
the Gulf of Maine Friday night into Saturday. High pressure
will build toward the region Sunday........
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
Our focus Friday night into Saturday will be on hurricane Dorian and
any effects the system may have on our area. Current guidance and
the official hurricane track take the system about 250 miles south
of the Downeast coast Saturday morning. This may be close enough for
clouds to move onto the Downeast coast late Friday night and some
wind and rain to brush the coast on Saturday. The biggest effect
along the coast may be high seas, mainly during the morning and
midday Saturday, which could reach 6 to 9 feet. All interests
Downeast and on our offshore waters are advised to follow forecast
updates this week as the track is still uncertain and subject to
some change. Dorian will likely quickly continue east, south of Nova
Scotia late Saturday into Saturday night as a corridor of dry air
and north winds follow behind the departing storm. A shortwave
trough diving in from the northwest may then bring increasing
clouds, mostly over the north, late Saturday night with some spotty
showers possible over the north by early Sunday morning. Otherwise,
Sunday will likely be mostly cloudy over the north as moisture
pooled in the approaching trough passes across. Downeast should
remain drier with a partly sunny sky. Weak high pressure should then
build in to bring partly cloudy and cool weather early next
week.........
posted by Advackia at 8:40 PM
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