256
FXUS62 KCHS 051733
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
133 PM EDT Sun May 5 2024

.SYNOPSIS...
Atlantic high pressure will remain across the Southeast U.S.
through much of next week. A cold front will approach the area
on Friday.

&&

.NEAR TERM /THROUGH TONIGHT/...
A weak shortwave in GA has continued to progress southeast this
morning, with convection forming near Charleston County. The
associated PV with this wave will meander east off of the coast
this morning with skies clearing across most of the area. The 850
MB temperature from the 05.12z KCHS sounding was around 13
degrees C, and with full mixing this would support high
temperatures in the mid 80s. The other thing noted from this
mornings sounding was the 1.47" PWAT, or a mostly saturated
column. However, the sounding was released with a shower close
by, so this might be over representing the ambient environment.
Either way, MLCAPE values are supposed to be around 1000 J/kg
this afternoon with scattered showers and thunderstorms forming
along an inland moving sea breeze.

This evening, convection should steadily decrease across the
forecast, owning to the sea breeze advancing inland and the
environment stabilizing after sunset. Patchy fog could develop late
tonight, especially over areas of recent rainfall. Low temperatures
should favor values between 65-70 degrees.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
A mid-level ridge axis will be positioned just off the Southeast
coast as a shortwave lifts northeast across the Tennessee Valley
Monday into Tuesday. Broad Atlantic high pressure will remain the
primary surface feature through the period as a low rides across the
northern CONUS. Convection will be active Monday with the quick
return of deep moisture. Coverage of showers/thunderstorms will be
highest in the late afternoon when instability is maximized. The
greatest POPs, which top out between 60-70%, are focused in
southeast South Carolina and along the I-95 corridor owing to the
juxtaposition of upper forcing and a progressive sea breeze. Chances
for showers/thunderstorms will be slightly less Tuesday as the
deeper moisture and remnant shortwave energy moves off the Mid
Atlantic coast in the morning. Although the majority of the forcing
will shift offshore, CI could occur along the sea breeze mainly
along and west of I-95. A weak ridge will set up Wednesday and
little available moisture will keep showers/precip limited.

Temperatures will steadily warm each day with highs in the mid 80s
Monday and increasing to the low 90s Wednesday. High temperatures
Wednesday could even reach record territory (see Climate section
below). Min temperatures both Monday and Tuesday are only expected
to drop to the mid/upper 60s, with locations along the beaches and
Downtown Charleston in the lower 70s.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
Rainfall chances are little to none to start the long term forecast
period as the flow aloft transitions to quasi-zonal. Temperatures
will rise into the low/mid 90s Thursday, once again approaching
record highs. Dew points will remain in the 60s, which will help
keep heat indices from reaching the 100 degree mark. A cold front
will approach Friday, pushing across the forecast area Friday night
into Saturday, and bringing the next chances for decent convective
rainfall. Dry conditions and relatively cooler temperatures (upper
70s/low 80s) are anticipated next weekend behind the front.

&&

.AVIATION /17Z SUNDAY THROUGH THURSDAY/...
KJZI: An afternoon sea breeze has already moved inland, or past
Charleston Executive and therefore VFR conditions are forecast
this afternoon. Showers and thunderstorms that do form this
afternoon, will likely be along the sea breeze or inland of the
terminal. Expect south/ southeast winds to persist this
afternoon and be gusty at times. Overnight, VFR conditions are
forecast. There is a slight chance of some patchy fog, but
overall conditions don`t look to conducive. The crossover
temperature at KJZI is 68 degrees, with low temperatures not
forecast to get below that. Monday, a leftover MCV will approach
the terminals from the west. Current TAFs aren`t advertising any
mention of thunder, but this will likely need to be added in
future TAF issuances.

KCHS/ KSAV: The sea breeze has currently just passed KSAV and is
very close to KCHS. Convection has developed along the boundary
and is forecast to continue through the afternoon hours. Both of
these terminals are carrying a tempo for thunder this afternoon
until the sea breeze moves far enough inland to bring an end to
convection. Overnight, VFR conditions are forecast. There is a
slight chance of some patchy fog, but overall conditions don`t
look to conducive. The crossover temperature at KCHS/ KSAV is
66 degrees, with low temperatures not forecast to get below
that. Monday, a leftover MCV will approach the terminals from
the west. Current TAFs aren`t advertising any mention of
thunder, but this will likely need to be added in future TAF
issuances.

Extended Aviation Outlook: Brief flight restrictions are possible
within scattered showers/thunderstorms Monday and Tuesday.

&&

.MARINE...
The surface pattern will yield south-southeast winds between 5-10
kts today, then increasing to 10-15 kts tonight. Wave heights are
forecast to favor values between 2-3 ft today and tonight.

Monday through Friday: Atlantic high pressure will maintain
relatively benign conditions over the local marine waters.
Southeasterly winds in the morning will back slightly during the
afternoon and evening hours each day as the sea breeze develops.
Winds will average 10-15 kt with seas 2-4 ft. Winds will surge near
the end of the week as a cold front approaches. Small Craft Advisory
conditions are possible as gusts approach 25 kt, but look marginal
at this juncture.

&&

.CLIMATE...
May 8:
KCHS: 93/1986

May 9:
KCHS: 95/1963
KSAV: 95/1962

&&

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

&&

$$

NEAR TERM...Haines/NED
SHORT TERM...BRM
LONG TERM...BRM
AVIATION...BRM/Haines
MARINE...BRM/NED