National Weather Service Raw Text Product

239 
FXUS62 KCHS 080530
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
130 AM EDT Sat Oct 8 2016

.SYNOPSIS...
Hurricane Matthew will move north along just offshore of the coast
of Southeast Georgia and Southeast South Carolina late tonight
and Saturday. The hurricane will move away from the forecast area
Saturday night and high pressure will begin building in
thereafter.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
We have seen a few weak couplets moving rapidly west through the
Charleston quad-county area, and it is here that there may still
be a non-zero risk for a brief, isolated tornado. However, this is
not enough to justify a Watch.

The western eyewall moved through Gray's Reef (Buoy 41008) around
midnight, and the winds were strong enough to break the wind
sensor. So the highest speed was 78 mph prior to the eyewall
reaching the site. Pressures bottomed out at 959 mb at that site. 

There has been a slight jog back to due north of Hurricane Matthew 
rather than east of due north from earlier. We certainly hope this
is only temporary, but due to this since the eyewall is
approaching the coast from Tybee to Hilton Head, we have a Special
Weather Statement in effect for hurricane force wind gusts to
likely occur overnight in and near these coastal communities.

Fortunately the eye has become exposed on the south side and it is
likely that the hurricane has weakened some. We'll know more with
updates from NHC overnight. 

Matthew's eye is forecast to come uncomfortably close to the
Charleston Metro area with the potential for the western eye wall
to brush areas such as Kiawah Island, Folly Beach, Downtown
Charleston, Mount Pleasant, Isle of Palms and Sullivan's Island
with gusts in excess of 100 mph.

The worst conditions will occur overnight into Saturday. Solid
tropical storm conditions are expected with hurricane conditions,
particularly in frequent gusts expected

IT IS IMPORTANT TO STRESS...any slight deviation to the right or
left of this track could significantly alter what level of
impacts are realized.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH MONDAY/...
Matthew will be well off the coast Sunday and starting to loop
around to the south by Monday. Meanwhile, broad high pressure to our
north will be building into the area, bringing drier conditions and
tranquil weather. Aloft, heights will rise as a ridge moves over the
east coast late Monday. The result of this pattern will be a rain-
free forecast across our entire area Sunday. Some showers may form
far offshore on Monday, but no rain is expected over land.
Temperatures will be in the 70s each day and the 50s Sunday Night.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
Virtually no change in the forecast thinking for the long term
period. Matthew is still forecast by many long term models to loop
around off the southeast coast as high pressure prevails inland
across the forecast area. The inland high pressure and prevailing
north to northeast flow will continue through Thursday with just
slight chance to chance PoP's across the coastal waters at times.
Through the period, temperatures will gradually warm, reaching near
normal values by Thursday.

&&

.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
Tropical storm conditions will continue to impact the terminals
through into Saturday, before improving conditions develop later
Saturday and Saturday Night, first at KSAV than at KCHS.

Extended Aviation Outlook: Improving conditions late Saturday as
Hurricane Matthew moves away from the coast. Gusty northerly winds
may continue Sunday and Monday, especially along the coast.

&&

.MARINE...
Overnight: Tropical Storm conditions will continue northern
waters during the early overnight, before hurricane conditions
overspread the area before morning. On the central and southern
waters hurricane force winds will prevail overnight. A Hurricane
Warning remains in effect for all legs. Seas could reach in excess
of 30 ft along and east of the Matthew's eye.

Sunday through Wednesday: Matthew will be well offshore Sunday while
high pressure builds in from the north. The interaction between
these two features will create a strong pressure gradient across the
coastal waters. Winds and seas will be high enough to warrant Small
Craft Advisories through at least Tuesday. Conditions will start to
improve on Wednesday as the gradient weakens.

Rip Currents: High risk of rip currents into the weekend due to
Hurricane Matthew.

&&

.HYDROLOGY...
The risk for flash flooding will continue into Saturday as
Hurricane Matthew makes its closest approach to the area.
Additional rainfall amounts will range from 8 to 14 inches, except
3 to 7 inches across interior Southeast Georgia.

It is highly likely that the combination of very heavy rainfall and
high surge will lead to a widespread flooding event for low-lying
coastal areas, especially downtown Charleston and possibly
downtown Savannah. Excessive fresh water flooding with high surge
could make for a dangerous situation for the coastal counties.
Flooding in Downtown Charleston could be worse than what was
observed during the October floods of last year.

&&

.TIDES/COASTAL FLOODING...
**Worst timing in regards to the approach of Matthew in sync with
 high tide overnight.**

Tide levels are approaching the record crest of 12.21 ft MLLW at
Fort Pulaski set in 1979 from Hurricane David. At Charleston the
levels are at their 3rd highest on record and greatest since
Hurricane Hugo in 1989.

This is an extremely dangerous situation for coastal areas and in
downtown Charleston, as well as in and near Tybee Island, which
will be cut of from the mainland.

Many beach communities will see extensive damage to beach front
properties due to a combination of large breaking waves, high
surge and dangerous winds. Homes at Edisto Beach where already
being undermined at a high tide earlier and Tybee Island saw
significant flooding along the beach front. Expect considerably
worse conditions overnight and it can not be stressed enough that
how dangerous this scenario is.

The forecasted inundation continues to be 6-9 ft for South
Carolina and Georgia. Some coastal locations will experience the
worst storm surge since Hurricane Hugo with devastating impacts.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...Flash Flood Watch through late tonight for GAZ087-088-099>101-
     114>119-137>141.
     Tropical Storm Warning for GAZ087-088-099>101-114-115-137. 
     Hurricane Warning for GAZ116>119-138>141. 
     High Risk for Rip Currents through this evening for GAZ117-119-
     139-141.
SC...Flash Flood Watch through late tonight for SCZ040-042>045-
     047>052.
     Tropical Storm Warning for SCZ040-042-043. 
     Hurricane Warning for SCZ044-045-047>052. 
     High Risk for Rip Currents through this evening for SCZ048>051.
MARINE...Hurricane Warning for AMZ330-350-352-354-374. 
&&

$$
NEAR TERM...
SHORT TERM...
LONG TERM...
AVIATION...
MARINE...
HYDROLOGY...
TIDES/COASTAL FLOODING...