-- Discussion containing changed information from previous version are highlighted. --
949
FXUS62 KCHS 261323
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
923 AM EDT Sun May 26 2024

.SYNOPSIS...
Hot conditions are expected through Memorial Day. A cold front
will move into the region Monday night and stall into mid week.
High pressure will return for the second half of the week.

&&

.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
No changes were made with the mid-morning update, forecast is
on track.

Today through This Evening: The region will remain aligned
along the western flanks of a southwest-northeast oriented
subtropical ridge that extends from the eastern Gulf of Mexico
to just offshore of the Southeast U.S. coast today. A weak
perturbation is forecast to cross the area this afternoon and
evening as the local area remains pinned between Atlantic high
pressure offshore and lee-side trough extending from the Upstate
into western Virginia. Most of the morning hours looks to
remain rain-free, but rain chances will begin to increase away
from the coast late this afternoon into this evening as strong
mixed layer instability featuring MLCAPE 2000-2500 J/kg develops
within a ribbon of higher 850 hPa theta-e located across the
interior.

Vertical cross section suggest the approaching mid-level
perturbation will not result in a tremendous amount of forcing,
but enough will be present to support isolated showers/tstms.
Most of this activity looks to develop across the Midlands and
CSRA by mid-afternoon, which will then propagate into the far
interior areas by late afternoon and continue into the early
evening hours. Despite the development and inland push of a
modest resultant sea breeze circulation, considerably lower 850
theta-e values and resulting unfavorable K-indices will likely
preclude the development of deep convection across the coastal
counties. The only exception could be across parts of coastal
Colleton and Charleston Counties where activity over the
Midlands could make a run for the middle South Carolina coast
this evening. Slight chance pops were highlighted across the
interior and into the Charleston Metro Area this afternoon and
evening. Modified soundings support DCAPE values of 1000-1400
J/kg with steep low-level lapse rates near 7.0 C/km so there
will be risk for damaging winds with any tstms that develop with
the greatest chances occurring roughly along/north of Walterboro
to Johns Island line coincident with the corridor of highest
850 theta-e values. A low-end risk for marginally severe hail
also exists with WBZ heights holding around 11.5 kft; however,
hail stones will tend to melt fairly quickly as they fall
through an increasing warm sub-cloud layer.

It will be another seasonably hot and humid day with highs
warming into the lower 90s with a few mid 90s possible in a few
areas. These temperatures combined with moderate levels of
humidity will support heat indices in the 98-101 range.

Overnight: Dry conditions will prevail into early Monday
morning once evening convection dissipates. A little ground fog
could develop prior to daybreak, but no major issues/impacts are
expected. It will be warm/humid night with lows only dropping
into the lower 70s with mid 70s at the coast and beaches. The
record high minimums could be challenged, mainly at the
Charleston AFB/International Airport (KCHS) and Downtown
Charleston (KCXM), but current data suggest values will fall
just short of record levels.
-- End Changed Discussion --

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
The forecast area will be situated between offshore high pressure
and a cold front approaching from the west on Monday. Aloft,
broad troughing shifts towards the East Coast, pushing the
ridge axis offshore. Consensus keeps at least the first half of
the day dry, then upstream convection could move into the area
later in the afternoon and into the evening/overnight. Still
unsure of how much coverage there will be when this occurs but
at least scattered showers and thunderstorms will be possible.
Some of this activity could be more organized when it arrives.
Primary threat with any stronger storms would be damaging wind
gusts. Otherwise, expect another hot day with highs reaching the
low 90s in most locations. Lows Monday night will largely be
around 70 or in the lower 70s.

The aforementioned front will then stall in the vicinity into
mid week. PWats fall and trends have continued to show a drier
forecast for Tuesday. Shouldn`t see more than just isolated
showers and thunderstorms, particularly along the coast. A dry
forecast is in place for Wednesday. Highs both days peak in the
upper 80s to lower 90s.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
High pressure will be the primary surface feature Thursday into
the weekend. Aloft, mid level wave passes over the Northeast
and Mid- Atlantic, before shifting offshore late week. This
period should be mostly dry, aside from some diurnal rain
chances returning over the weekend. Temperatures will be near
normal.

&&

.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
26/12z TAF Discussion:
KCHS/KJZI/KSAV: VFR for much of the period. Satellite shows a
small pocket of stratus centered just south of KRBW. These
clouds may get close to KCHS at daybreak, but latest trends
suggest a slight erosion along the cloud bank`s eastern flanks.
There are no plans of including stratus at this time unless
last minute trends suggest otherwise prior to issuance time.
Isolated showers/tstms are expected this afternoon and evening
with the best chances holding inland from the terminals. Some of
these could make a run for KCHS by early evening, but
confidence of activity that terminal is too low to justify a
mention at this time.

Extended Aviation Outlook: Brief flight restrictions are
possible in showers/thunderstorms Monday afternoon into Tuesday.

&&

.MARINE...
Today: West winds will turn more southerly this afternoon with
the development of a modest resultant sea breeze circulation.
Winds along the land/sea interface, including Charleston Harbor,
could get a bit elevated for a few hours this afternoon with
winds in the Harbor reaching 15 kt with gusts to 20 kt. Onshore
winds coupled with an outgoing tide could make for locally rough
conditions in the Harbor late this afternoon. Seas will average
1-2 ft.

Tonight: Southerly winds around 10 kt will persist through the
night. A few tstms could move off the Charleston County coast
later this evening bringing a risk for convective wind gusts in
excess of 34 kt and cloud-to-water lightning.

Monday through Friday: Marine conditions remain below Small Craft
Advisory levels through the week. South to southwest will largely
persist through midweek until a cold front pushes east of the
waters. High pressure will be the dominant feature for late week.
Winds will average 15 knots or less and seas 2-3 feet, with
occasional 4 feet early in the week.

&&

.CLIMATE...
Record High Minimum Temperatures:

May 27:
KCHS: 76/1991
KCXM: 79/2019
KSAV: 77/1878

May 28:
KCHS: 76/2000
KCXM: 80/2000
KSAV: 76/1885

&&

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

&&

$$

NEAR TERM...
SHORT TERM...
LONG TERM...
AVIATION...
MARINE...