National Weather Service Raw Text Product

476 
FXUS62 KCHS 251149
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
749 AM EDT Wed Jun 25 2025

.SYNOPSIS...
Hot and humid conditions are expected to continue with rain
chances increasing today into late week as surface troughing
begins to form near the region and a few upper disturbances
pass through. A few thunderstorms may become strong to severe
on Wednesday. 

&&

.NEAR TERM /THROUGH TONIGHT/...
Today: Aloft, a large/strong ridge will remain centered across 
KY/TN, encompassing much of the Mid-Atlantic and Southeast, but 
should begin to show some signs of weakening and/or nudging just 
inland to the local area as a broad mid-upper lvl low across the 
western Atlantic drifts across Florida and Southern Georgia. Much 
like the previous few days, warm and humid conditions will transpire 
along the western periphery of the Atlantic high, with pockets of 
dry air depicted on water vapor and in local model soundings 
suggesting a rather limited scenario for afternoon convection to 
develop, at least into early afternoon hours. Strong sfc heating 
prior to any convection under mostly sunny/partly cloudy skies along 
with 1000-850 mb thicknesses support temps to warm into the mid-
upper 90s again this afternoon, warmest away from coastal areas. 
Some mixing out of sfc dewpts is also expected heading into 
afternoon hours, limiting the duration of max heat index values 
across the local area today. Still, many areas could experience heat 
index values reaching the 104-107 range this afternoon, especially 
if showers/thunderstorms do not occur during peak heating hours. 
There is a limited risk for a few spots to touch heat index values 
up to 108-109 degrees early afternoon, but the duration should be 
fairly short and likely occur with moisture pooling along an 
inland moving sea breeze. For this reason, a Heat Advisory has 
not been issued, but conditions will continue to be monitored 
for the need in case the situation changes. 

A few showers and/or thunderstorms can not be ruled out along/ahead 
of the sea breeze this afternoon, especially given the approach of 
the mid-upper lvl low to the east-southeast. Given the expectancy
of high instability locally due to strong sfc heating and low-
lvl moisture, an isolated strong and/or severe thunderstorm can 
not be ruled out later this afternoon, mainly pulse like in 
nature and capable of producing damaging winds. However, the more
notable severe weather concern is likely to occur during evening
hours. 

This Evening: A broad mid-upper lvl low centered off the Southeast 
Coast will slowly nudge eastward with time, forcing the large-scale 
ridge to retreat further inland. Vort energy wrapping around the 
north/northwest periphery of the low could play a key role in the 
development of showers/thunderstorms developing across a broad 
region of sfc troughing over the Carolinas (starting across North 
Carolina), with a bulk of global and hires models suggesting 
activity to congeal/broadly organize into a cluster within a modestly
sheared environment, then tracking south-southwest, primarily 
just inland to the local area near the arriving sea breeze. However,
cold pooling could easily allow activity to reach inland counties
of Southeast South Carolina and Southeast Georgia in a severe 
state, and to a lessor degree coastal counties, mainly across Southeast
Georgia. Locally, environmental conditions are rather impressive
across inland areas ahead of this activity, with SBCAPE around
3500 J/kg, low-lvl lapse rates around 8.5 C/km, DCAPE near the 
1200-1400 J/kg range and inverted-v soundings suggestive of 
thunderstorms with damaging wind potential should they occur 
locally. There is even some risk for small hail, but this will 
be secondary concern. The primary time-frame for severe weather 
remains between 6PM to 12AM this evening.

After Midnight: Weak shear and loss of diurnal heating will 
eventually take a toll in regards to cold pooling and thunderstorm 
intensity. However, showers and general thunderstorms remain in the 
forecast across southern areas into late night. Temps will remain 
very mild prior to shower/thunderstorm activity, but should 
eventually dip into the lower 70s inland to mid 70s near the beaches.

&&

.SHORT TERM /THURSDAY THROUGH SATURDAY/...
The upper-lvl ridge situated over the Mid-Atlantic that has been 
sitting across the Southeastern CONUS the last couple of days will 
continue to break down throughout Thursday and Friday as it moves 
offshore over the weekend. With this transition, expect a more 
typical summertime pattern to finally setup for the next couple of 
days. Remnant vorticity from an MCS on Wednesday combined with a 
weak upper-lvl low meandering across Florida might yield the chance 
for showers and thunderstorms to form in the afternoons on Thursday 
through Saturday. At the surface, an extensive field of moisture 
will remain over the Southeast with PWAT values ranging from 1.50 to 
1.75 inches throughout the period. This will be more than enough 
moisture to spark up some showers and thunderstorms each afternoon 
as the sea breeze pushes inland. In addition, SPC has most of the 
region highlighted by a level 1 out of 5 risk for severe weather on 
Thursday with the primary concern being locally damaging wind gusts. 
Overnight lows will remain mild and only dip into the low to mid 70s.

&&

.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
This weak upper-lvl low will continue to meander across Florida 
before eventually dissipating on Sunday. A more zonal pattern will 
setup over the Southeast and ensembles continue to indicate daily 
chances of rain through early next week. Temperatures will remain 
slightly above normal for this time of the year.

&&

.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
VFR conditions will prevail at CHS/JZI/SAV terminals through 12Z
Thursday. However, there is some risk for an afternoon shower 
or thunderstorm impacting the terminals with a sea breeze 
shifting inland, followed by another risk for showers/thunderstorms
during evening hours. At this time, probabilities remain too 
low to include mention of SHRA/TSRA at the terminals this 
afternoon, and the bulk of convection during evening hours 
appears to remain inland to the terminals. Future TAF issuances 
could need to include mention of this activity.

Extended Aviation Outlook: VFR will mainly prevail throughout the 
period, however brief flight restrictions are possible within 
showers and thunderstorms that develop in the afternoon and/or 
evening.

&&

.MARINE...
Today and Tonight: Atlantic high pressure will prevail for a bulk of 
the day and into tonight, favoring conditions that remain well below 
Small Craft Advisory levels through tonight. In general, a southwest 
wind will gradually turn south mid-late morning, then peak in the 10-
15 kt range as a sea breeze develops and pushes inland. A few showers
and thunderstorms could arrive to coastal areas late evening and
after midnight tonight, producing higher wind gusts, seas and 
some risk for severe weather across Georgia waters, but outside 
this activity, winds are expected to return to southwest and 
remain around 10 kt or less. Seas will generally range around 2 ft.

Thursday through Sunday: As a weak ESE swell continues to mix in, 
seas will remain around 1 to 3 ft. Expect generally southerly winds 
at 5 to 10 kt to prevail throughout the period. It could become a 
bit gusty each afternoon with gusts up to 15 to 20 kt as the 
seabreeze pushes inland (gusts strongest across the immediate 
coastline and the Charleston Harbor). Otherwise, no marine concerns 
expected.

Rip Currents: A 1.5 ft, 7-8 second swell will impact the beaches 
along with a 10-15 kt onshore wind today. Given these conditions are 
similar to yesterday with several rip currents reported along Tybee 
Island, GA, a Moderate Risk for rip currents is in place along 
Georgia beaches through this evening.

&&

.TIDES/COASTAL FLOODING...
Astronomical tides will peak around 6.5 ft MLLW at Charleston 
with this evening's high tide cycle. Late afternoon winds will 
only be marginally supportive of increasing tidal departures. 
This evening's high tide will likely peak around 6.8-6.9 ft 
MLLW, falling just short of Coastal Flood Advisory criteria.

&&

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

&&

$$

NEAR TERM...DPB
SHORT TERM...Dennis
LONG TERM...Dennis
AVIATION...Dennis/DPB
MARINE...Dennis/DPB