Area Forecast Discussion
Issued by NWS Charleston, SC

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS62 KCHS 201948
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
348 PM EDT Sun May 20 2018

.SYNOPSIS...
A tropical air mass will remain in place through the week between
Atlantic high pressure to the east and low pressure to the west.

&&

.NEAR TERM /THROUGH TONIGHT/...
Isolated to scattered convection developing along/head of the
sea breeze will gradually cluster across the interior through
sunset. Meanwhile, patchy light rain over the Atlantic waters
will gradually diminish as it approaches the beaches. Convection
is diurnally driven so any lingering convection will quickly
diminish after sunset. Expect a mainly dry night to prevail as
low-level convergence shifts back along the western wall of the
Gulf Stream. Could see isolated showers pop up along the lower
South Carolina coast a few hours prior to daybreak where
some high mesoscale guidance shows some weakly enhanced surface
moisture convergence developing, but confidence is not high
enough to justify the placement of any mentionable pops at this
time. Could see a little fog/stratus across mainly the coastal
counties late, but think there will be enough high cloudiness in
place to keep these elements under control. It will be warm,
humid night with lows ranging from the upper 60s/near 70 well
inland to the lower-mid 70s at the coast and beaches, including
Downtown Charleston.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
In general, the area will remain between Atlantic high pressure to
the east and lower pressure and weak upper level troughing to the
west. This pattern, along with adequate deep layer moisture, will
result in scattered to possibly numerous showers each day. Have
continued to minimize the mention of thunder given the model
soundings holding CAPE values to mostly less than 1,000 J/Kg each
day. Hard to pin down what day has the highest probabilities for
rain, but still looks like moisture and weak upper forcing might be
slightly higher on Tuesday. High temperatures each day near to
slightly above normal, with lows continuing mild/above normal, in
the upper 60s to lower 70s.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
Atlantic high pressure should extend west over the area through the
period while low pressure persists to the west. This pattern will
maintain the warm and muggy conditions with some heavy rain at
times. In general it looks like temperatures will be near to
slightly above normal.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
VFR. Shower/tstm activity is expected to remain west of the
terminals this afternoon. There is a chance for MVFR cigs
redevelop just before sunrise, but guidance is not in agreement
on this potential. Limited clouds to SCT020 for now 09-13z.

Extended Aviation Outlook: With the combination of a weak upper
trough/lower pressure inland and sufficient tropical moisture,
expect scattered mainly afternoon showers/thunderstorms each day
with brief flight restrictions possible.

&&

.MARINE...
Tonight: Southerly wind regime will persist with winds 10 kt
or less. Seas will average 2-4 ft nearshore waters and 4-5 ft
offshore waters.

Monday through Friday: No highlights expected through the
period. Lower pressure will remain inland and higher pressure to
the east. This will maintain a south-southeast winds of 15
knots or less and seas 3 to 5 feet, highest beyond 20 nm
offshore.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
MARINE...None.

&&

$$



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.