836
FXUS62 KCHS 150020
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
820 PM EDT Sun Jul 14 2024

.SYNOPSIS...
Atlantic high pressure to the east and a weak inland trough
will extend across the region through the middle of next week.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
Heat index values are quickly falling across the area and the
Heat Advisory has been expired.

Only a few isolated storms left across the region at sunset as
the sea breeze has progressed inland and will push west of the
coastal plain within the next hour or so. Debris clouds will be
fairly limited this evening, but elevated low level moisture
and a weak but persistent BL gradient will keep radiation weak,
with warm and humid conditions through the night. In general,
low temps will range from the mid 70s inland to the upper 70s
across coastal counties. Along the beaches, low temps should
range in the lower 80s.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
Monday and Tuesday: The region will remain on the western periphery
of a deep layer Atlantic ridge. Generally south-southwest low level
flow with continued hot and humid conditions. Have kept chance PoPs
for afternoon and early evening showers and thunderstorms. Main
initiator of scattered convection will be the seabreeze and other
low level boundaries/outflow boundaries. PWs around 2 inches, along
light steering flow will again bring the potential for locally heavy
downpours with any stronger showers/thunderstorms.

Guidance continues to indicate Heat Advisory conditions will be
likely on Monday and less likely on Tuesday. Highest heat indices
along and east of I-95. Will not issue any Heat Advisories at this
point for Monday, given we already have one in place for
today/Sunday.

Wednesday: The deep layer Atlantic Ridge starts to retreat a bit
eastward as a broad upper level trough forms well northwest of the
region, over the Great Lakes and OH River Valley regions. Given a
little more cyclonic upper level flow, and continued deep/tropical
moisture with PWs 2+ inches, expect higher coverage of convection
than previous days. However, given it is still day 4, have capped
PoPs at high end chance. Given higher convective coverage, feel max
Heat Indices will remain just below Advisory, although cannot rule
out a few spots reaching the 108 threshold.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
A weak upper level trough gradually weakens to the northwest of the
area, while a deep layer Atlantic ridge gradually builds back
westward. Model guidance continues to be rather bullish with PoPs in
the likely or even higher categories for much of this period. Given
the typical uncertainty this far out, have continued to undercut
blended model PoPs a tad, keeping them in the high chance to low end
likely range. Temperatures near to possibly slightly below normal,
especially the max temperatures, due to higher than climo PoPs/cloud
cover potential.

&&

.AVIATION /00Z MONDAY THROUGH FRIDAY/...
Overnight will feature mainly dry conditions across the area.
Elevated low level moisture will again limit the radiation
cooling potential, and another warm/muggy night is on tap. Some
shallow/patchy/light fog is again possible late tonight, but the
probability of impacts at any of the terminals is too low to
justify inclusion in the TAF at this point.

Monday will bring another summerlike day, with light winds in
the morning becoming S in the afternoon, and scattered afternoon
thunderstorms along and ahead of the sea breeze front. The
mainly threat for any flight restrictions will come if
showers/storms move over the terminals Monday afternoon, but
confidence in coverage and timing is too low to include any
mentions in the TAFs at this point.

Extended Aviation Outlook: Through mid week: Brief flight restrictions
will be possible with scattered afternoon showers/tstorms at
all terminals, mainly late morning through early afternoon.
Chances for showers/thunderstorms may begin to increase a bit by
mid week, increasing the risk for flight restrictions.

&&

.MARINE...
Tonight: A fairly weak pressure gradient will prevail along the
western periphery of high pressure across the Atlantic and a trough
well inland. South to southeast winds upwards to 10-15 kt are
possible this evening, before winds tip back to southwest overnight.
Seas will average 2-4 ft.

Monday through Tuesday night: No highlights are expected as a
deep layer Atlantic ridge remains centered east of the waters.
Expect south- southwest winds of 15 knots or less and seas of 2
to 4 feet, highest beyond 10 or 20 nm offshore. Scattered mainly
late night through morning showers and thunderstorms.

Wednesday and Thursday: Models show the low level pressure gradient
to increase as an upper level trough develops well northwest of the
waters over the OH River Valley and Great Lakes. South-southwest
winds of 10-20 knots, with some gusts of 20-24 knots possible. Seas
3 to 5 feet, highest well offshore. Still feel conditions will
remain below SCA levels. Scattered to numerous mainly late night
through morning showers and thunderstorms.

&&

.CLIMATE...
Record High Minimum Temperatures:

July 15:
KCHS: 81/1981
KCXM: 82/2023
KSAV: 80/1981

July 16:
KCHS: 78/2023
KCXM: 82/2021
KSAV: 82/1883

&&

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

&&

$$

NEAR TERM...CEB/DPB/RFM
SHORT TERM...RFM
LONG TERM...RFM
AVIATION...CEB/RFM
MARINE...DPB/RFM