Area Forecast Discussion
Issued by NWS Charleston, SC
FXUS62 KCHS 281132
Area Forecast Discussion
National Weather Service Charleston SC
732 AM EDT SAT MAY 28 2016
Tropical Depression Two over the southwest Atlantic will approach
the South Carolina coast through tonight, before moving onshore
over Sunday before weakening. The low could linger in the vicinity
into early next week before eventually lifting away to the northeast.
A cold front will approach the region late next week.
.NEAR TERM /THROUGH TONIGHT/...
Today: Tropical Storm Warnings remain in effect for the South
Carolina Coastal areas. This ahead of the early season tropical
system expected to remain a depression for much of the day prior
to reaching the Gulf Stream tonight. Deep moisture will continue
to advect into the Coastal Carolinas today with bands of showers
expected to increase in coverage across Eastern South Carolina;
especially during the afternoon hours from Beaufort northward.
Widespread clouds will hold temps down into the lower 80s across
northern zones. Across inland Georgia, only some high clouds to
start the day and models indicate a fair amount of destabilization
by the afternoon. we maintain a slight chance of showers and tstms
to the west of I-95 this afternoon as convection will tend to be
more diurnal bound on a decent 850 MB theta-e ridge across our
inland Georgia Zones. It will become breezy along coastal areas
this afternoon as the sea breeze develops along with various
mesoscale shower bands.
Tonight...The tropical low will reach the Gulf Stream waters and
just about all of the model guidance indicates that any strengthening
should be modest as upper level wind shear atop the system is
forecast to remain rather substantial. Pops will be categorical
across across much of the Charleston Tri-County area as strong low
level convergence and deep tropical moisture with pwats of 2
inches or better in place. Rain will likely be heavy at times with
potential for tstms. Most of the rain will likely fall to the
north of the Savannah River overnight. Winds ahead of the tropical
system will ramp up along the coast with potential of tropical
storm force winds in the warning area.
.SHORT TERM /SUNDAY THROUGH TUESDAY/...
The forecast through the short term period continues to remain quite
complex and still somewhat uncertain, highly dependent upon the
evolution of Tropical Depression Two over the southwest Atlantic
between Bermuda and the Bahamas.
The official forecast from the National Hurricane Center continues
to track a weakening tropical storm/depression along coastal
Charleston County on Sunday Afternoon. Gusty winds associated with
the low are expected to gradually subside as the low either stalls
or hooks briefly before beginning to slide slowly to the northeast
sunday night. the ECMWF had an interesting solution on the 00Z run
with a good bit of upper forcing from a 45 kt upper jet streak enhancing
heavy rain across the South Carolina forecast area on the western
side of the surface low. The QPF differences between the models remain
quite substantial and revolve not only on complex mesoscale details
but on synoptic forcing and atop the system. We have bumped up QPF
to 2-3 inches across the Charleston Tri-County but some higher
amounts could fall back west into places like Hampton and Allendale
Due to the small and likely compact nature to the system there will
likely only be some occasional convective bands that contain thunder
storms, so we are showing no more than chance t-storms through the
period. If deep convection were to develop on a knot near the
center, there could be small chances for rotation given 25-30 kt
of deep layered shear but the window at this time appears too
small to play any tornado risk across Eastern Charleston and
Berkeley Counties.The risk for Tropical Storm force winds will be
highest Tonight into early Sunday as the storm reaches the coast.
the areas most likely to experience Tropical Storm winds with
gusts up to 40 mph, will be immediate coastal South Carolina,
including the Charleston metro. Winds of this magnitude may bring
down a few trees and powerlines. Some power outages are possible.
Model solutions still vary on the evolution of Tropical Depression
Two into Tuesday, but consensus slowly lifts the weakening low
northeast from north coastal South Carolina towards the North
Carolina Outer Banks by Tuesday. Thus, the main window for any
threats with this system will have ended. Assuming this track
holds, precipitation chances should decrease through the day
Monday as deepest moisture moves out of the area. Locations across
southeast Georgia could very well be dry much of the day given the
position relative to the low. Current forecast has PoPs ranging
from 40-50% north to around 20% in the south. On Tuesday, rain
chances revolve around the more typical summertime diurnal
convection. High temperatures will be near normal in the mid 80s
to around 90 (highest across southeast Georgia), with lows mainly
in the upper 60s to around 70.
.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
Models are in fairly good agreement for the long term period. Weak
pressure pattern will be in place for the latter half of the work
week as whatever remnants of the tropical system remains meanders
off the mid-Atlantic coast and eventually dissipates. A cold front
is then forecast to approach the region Friday into Saturday,
resulting in an increase in precipitation chances. Temperatures will
be near to slightly above normal as heights aloft build.
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
KCHS: VFR until later today. Could see cigs dropping to mvfr this
afternoon or evening, as Tropical Depression 2 approaches. Showers
associated with very out fringes of the system may develop in the
vicinity by mid to late morning, but greater chances still appear
to be in the late afternoon and evening hours. Diurnal enhancements
including the sea breeze will result in some wind gusts near 20 kt
this afternoon. Tonight rains will increase and become heavier,
winds should become gusty as the gradient tightens but have not
shown any gusts topping 20 kt as yet.
KSAV: VFR conditions will likely persist. Deeper moisture is
forecast to remain north of the terminal. There may be a few
spotty light showers around the area this morning and again this
afternoon into the overnight, but potential not enough to add any
vchs or shra to the KSAV terminal forecast.
EXTENDED AVIATION OUTLOOK...Chances for at least periodic flight
restrictions into early next week, especially at KCHS, as the
tropical system impacts coastal South Carolina.
Tropical Depression Two currently located around 265 miles southeast
of Charleston this morning will track northwest towards the area
today, and eventually move onshore somewhere in the vicinity of
Charleston Sunday afternoon. Winds/seas will deteriorate as result,
with tropical storm conditions expected over the nearshore SC waters
(including the Charleston Harbor) and portions of the outer Georgia
waters late tonight into Sunday, where Tropical Storm Warnings
remain in effect.
Some uncertainty still remains in the track of Tropical Depression
Two, but consensus has the low meandering in the vicinity early
Monday before slowly lifting to the northeast into Tuesday. Latest
National Hurricane Center forecast indicates that the system will
weaken as this occurs, so marine conditions are expected to steadily
improve. Thereafter, winds/seas should remain below any headline
criteria through late week.
Rip Currents: A high risk of rip currents all beaches today and
elevated risks into early next week.
GA...HIGH RISK FOR RIP CURRENTS through this evening for GAZ117-119-
SC...Tropical Storm Warning for SCZ045-047>052.
HIGH RISK FOR RIP CURRENTS through this evening for SCZ048>051.
MARINE...Tropical Storm Warning for AMZ330-350-352-374.