Hurricane #Florence Advisory 54: Florence Moving Steadily Toward the Carolina Coastal Areas.


Hurricane Florence Advisory Number  54
NWS National Hurricane Center Miami FL       AL062018
500 PM EDT Wed Sep 12 2018

...FLORENCE MOVING STEADILY TOWARD THE CAROLINA COASTAL AREAS...
...LIFE-THREATENING STORM SURGE AND RAINFALL EXPECTED...


SUMMARY OF 500 PM EDT...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...30.9N 72.5W
ABOUT 385 MI...615 KM SE OF WILMINGTON NORTH CAROLINA
ABOUT 420 MI...675 KM ESE OF MYRTLE BEACH SOUTH CAROLINA
MAXIMUM SUSTAINED WINDS...120 MPH...195 KM/H
PRESENT MOVEMENT...NW OR 315 DEGREES AT 16 MPH...26 KM/H
MINIMUM CENTRAL PRESSURE...949 MB...28.03 INCHES




WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY:

None.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Storm Surge Warning is in effect for...
* South Santee River South Carolina to Duck North Carolina
* Albemarle and Pamlico Sounds, including the Neuse and Pamlico
Rivers

A Storm Surge Watch is in effect for...
* Edisto Beach South Carolina to South Santee River South Carolina
* North of Duck North Carolina to the North Carolina/Virginia border



A Hurricane Warning is in effect for...
* South Santee River South Carolina to Duck North Carolina
* Albemarle and Pamlico Sounds

A Hurricane Watch is in effect for...
* Edisto Beach South Carolina to South Santee River South Carolina

A Tropical Storm Warning is in effect for...
* North of Duck North Carolina to the North Carolina/Virginia border

A Tropical Storm Watch is in effect for...
* North of the North Carolina/Virginia border to Cape Charles Light
Virginia
* Chesapeake Bay south of New Point Comfort



Interests elsewhere in the southeastern and mid-Atlantic states
should monitor the progress of Florence.

A Storm Surge Warning means there is a danger of life-threatening
inundation, from rising water moving inland from the coastline,
during the next 36 hours in the indicated locations. For a
depiction of areas at risk, please see the National Weather
Service Storm Surge Watch/Warning Graphic, available at
hurricanes.gov.  This is a life-threatening situation.  Persons
located within these areas should take all necessary actions to
protect life and property from rising water and the potential for
other dangerous conditions.  Promptly follow evacuation and other
instructions from local officials.

A Storm Surge Watch means there is a possibility of life-
threatening inundation, from rising water moving inland from the
coastline, in the indicated locations during the next 48 hours.

A Hurricane Warning means that hurricane conditions are expected
somewhere within the warning area.  A warning is typically issued
36 hours before the anticipated first occurrence of tropical-storm-
force winds, conditions that make outside preparations difficult or
dangerous.  Preparations to protect life and property should be
rushed to completion.

A Hurricane Watch means that hurricane conditions are possible
within the watch area.  A watch is typically issued 48 hours
before the anticipated first occurrence of tropical-storm-force
winds, conditions that make outside preparations difficult or
dangerous.

A Tropical Storm Warning means that tropical storm conditions are
expected somewhere within the warning area within 36 hours.

A Tropical Storm Watch means that tropical storm conditions are
possible within the watch area, generally within 48 hours.

For storm information specific to your area, including possible
inland watches and warnings, please monitor products issued by your
local National Weather Service forecast office.


DISCUSSION AND OUTLOOK
----------------------
At 500 PM EDT (2100 UTC), the center of Hurricane Florence was
located near latitude 30.9 North, longitude 72.5 West. Florence is
moving toward the northwest near 16 mph (26 km/h), and this general
motion, accompanied by a gradual decrease in forward speed, is
expected to continue through Saturday. On the forecast track, the
center of Florence will move over the southwestern Atlantic Ocean
between Bermuda and the Bahamas tonight, and approach the coast of
North Carolina or South Carolina in the hurricane warning area on
Thursday and Friday, and move slowly near the coastline through
Saturday.

Maximum sustained winds have decreased to near 120 mph (195 km/h)
with higher gusts.  Florence is a category 3 hurricane on the
Saffir-Simpson Hurricane Wind Scale.  Some fluctuations in strength
will be possible through Thursday morning.  Although slow weakening
is expected to begin by late Thursday, Florence is forecast to be an
extremely dangerous major hurricane when it nears the U.S. coast
late Thursday and Friday.

Hurricane-force winds extend outward up to 70 miles (110 km) from
the center and tropical-storm-force winds now extend outward up to
195 miles (315 km).

The estimated minimum central pressure is 949 mb (28.03 inches).


HAZARDS AFFECTING LAND
----------------------
STORM SURGE:  The combination of a dangerous storm surge and the
tide will cause normally dry areas near the coast to be flooded by
rising waters moving inland from the shoreline.  The water has the
potential to reach the following heights above ground if peak surge
occurs at the time of high tide...

Cape Fear NC to Cape Lookout NC, including the Neuse, Pamlico,
Pungo, and Bay Rivers...9-13 ft
North Myrtle Beach SC to Cape Fear NC...6-9 ft
Cape Lookout NC to Ocracoke Inlet NC...6-9 ft
South Santee River SC to North Myrtle Beach SC...4-6 ft
Ocracoke Inlet NC to Salvo NC...4-6 ft
Salvo NC to North Carolina/Virginia Border...2-4 ft
Edisto Beach SC to South Santee River SC...2-4 ft

The deepest water will occur along the immediate coast in areas of
onshore winds, where the surge will be accompanied by large and
destructive waves.  Surge-related flooding depends on the relative
timing of the surge and the tidal cycle, and can vary greatly over
short distances.  For information specific to your area, please see
products issued by your local National Weather Service forecast
office.

RAINFALL:  Florence is expected to produce heavy and excessive
rainfall in the following areas...

Coastal North Carolina...20 to 30 inches, isolated 40 inches. This
rainfall would produce catastrophic flash flooding and significant
river flooding.

South Carolina, western and northern North Carolina...5 to 10
inches, isolated 20 inches.
Elsewhere in the Appalachians and Mid-Atlantic states...3 to 6
inches, isolated 12 inches.




WIND:  Hurricane conditions are expected to reach the coast within
the hurricane warning area late Thursday or Friday.  Winds are
expected to first reach tropical storm strength on Thursday, making
outside preparations difficult or dangerous.  Preparations to
protect life and property should be rushed to completion.



TORNADOES:  A few tornadoes are possible in eastern North Carolina
beginning late Thursday morning.

SURF:  Swells generated by Florence are affecting Bermuda, portions
of the U.S. East Coast, and the northwestern and central Bahamas.
These swells are likely to cause life-threatening surf and rip
current conditions. Please consult products from your local weather
office.
Hurricane Florence Discussion Number  54
NWS National Hurricane Center Miami FL       AL062018
500 PM EDT Wed Sep 12 2018

Data from an Air Force Reserve hurricane hunter aircraft along with
satellite imagery and various intensity estimates indicate that
Florence has weakened instead of strengthening. However, while the
hurricane hasn't strengthened in terms of peak winds, the inner-core
and outer wind fields have continued to expand, resulting in an
increase the cyclone's total energy, which will create a significant
storm surge event. The upper-level outflow remains impressive and is
still expanding except toward the south.

Florence is moving toward the northwest or 315/14 kt. The new 12Z
global and regional model runs have come into much better agreement
on Florence moving steadily northwestward around a strong ridge
located between Bermuda and the U.S. mid-Atlantic region for the
next 48 hours or so. By late on day 2, Florence is forecast to
approach the southern portion of the North Carolina coast, then slow
down considerably and turn westward within collapsing steering flow,
with a very slow westward motion near the coasts of North and South
Carolina continuing into Friday and Saturday. Corrected-consensus
models HCCA and FSSE remain very close to each other and are quite
similar to the simple consensus model TVCA. Therefore, only a slight
eastward shift was needed to the previous forecast track through 36
hours or so, mainly due to the more eastward initial position based
on the reconnaissance fixes. At 48 hours and beyond, no significant
changes were required to the previous advisory track, which still
shows Florence moving slowly westward across South Carolina and
western North Carolina on day 4, followed by a slow northward motion
up the Appalachian mountain chain on day 5.

A narrow window of opportunity remains during the next 24 hours or
so for Florence to strengthen a little when the hurricane passes
over the warmer SSTs and deeper warm water/higher upper-ocean heat
content associated with the Gulf Stream, and low vertical shear
conditions of 5-10 kt will aid in any strengthening process.
However, significant strengthening is not anticipated due to
Florence's large and expanding inner-core wind field. By 36 h
and beyond, decreasing ocean heat content along with the slowing
forward speed of Florence will likely produce cold upwelling beneath
the hurricane, inducing a gradual weakening trend. When Florence
moves over the shallow coastal shelf waters in 48-72 h, land
interaction and more significant upwelling are anticipated, which
should further enhance the weakening process. The NHC intensity
forecast remains near the higher statistical guidance through 48
hours, then follows the trend of the decay SHIPS model after that
time.

Although the maximum winds are expected to weaken a little more,
Florence is still expected to remain a dangerous major hurricane as
it approaches the coast. The threat to life from storm surge and
rainfall will not diminish, and these impacts will cover a large
area regardless of exactly where the center of Florence moves.

Key Messages:

1. A life-threatening storm surge is now highly likely along
portions of the coastlines of South Carolina and North Carolina, and
a Storm Surge Warning is in effect for a portion of this area.  All
interests in these areas should complete preparations and follow any
advice given by local officials.

2. Life-threatening, catastrophic flash flooding and prolonged
significant river flooding are likely over portions of the Carolinas
and the southern and central Appalachians late this week into early
next week, as Florence is expected to slow down as it approaches the
coast and moves inland.

3. Damaging hurricane-force winds are likely along portions of the
coasts of South Carolina and North Carolina, and a Hurricane Warning
is in effect. Strong winds could also spread inland into portions
of the Carolinas.

4. Large swells affecting Bermuda, portions of the U.S. East
Coast, and the northwestern and central Bahamas will continue this
week, resulting in life-threatening surf and rip currents.

FORECAST POSITIONS AND MAX WINDS

INIT  12/2100Z 30.9N  72.5W  105 KT 120 MPH
 12H  13/0600Z 32.1N  74.1W  110 KT 125 MPH
 24H  13/1800Z 33.4N  75.9W  110 KT 125 MPH
 36H  14/0600Z 33.9N  77.1W  105 KT 120 MPH
 48H  14/1800Z 34.0N  77.9W  100 KT 115 MPH...NEAR THE COAST
 72H  15/1800Z 33.6N  79.2W   70 KT  80 MPH...NEAR THE COAST
 96H  16/1800Z 34.0N  81.7W   30 KT  35 MPH...INLAND
120H  17/1800Z 35.6N  83.4W   20 KT  25 MPH...POST-TROP/INLAND
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