Garnett, South Carolina Weather Forecast Discussion

849
FXUS62 KCHS 261854
AFDCHS
Area Forecast Discussion
National Weather Service Charleston SC
254 PM EDT Fri Sep 26 2025
.SYNOPSIS...
A weak front will approach the region today, and then likely
stall along the coastline through the weekend. Tropical low
pressure could approach the Southeast United States early next
week.
&&
.NEAR TERM /THROUGH TONIGHT/...
The mid-levels will consist of a positively tilted trough
stretching from the OH Valley into the Lower MS Valley this
evening. It`ll become north to south oriented overnight,
stretching from the Great Lakes Region into the Deep South.
Additionally, an embedded Low will start to develop along it`s
southern extent, near the TN Valley. At the surface, a cold
front will extend across the Appalachians this evening. It`ll
slowly approach our area overnight, becoming located just to the
west our our area by daybreak Saturday. This overall pattern
will will lead to southwesterly flow, ushering deep moisture
into our area. PWATs should be ~2", which is above normal for
this time of year. Both the CAMs and the deterministic models
have convection this evening and overnight, with an axis of
increased coverage and intensity across portions of our area.
We tried to capture this with the hourly POPs/Wx grids. While
there is some instability and shear, the widespread severe
threat is low. The bigger concern is locally heavy rainfall. But
these storms should be pretty progressive, so the heavy rain
threat will mostly come from locations seeing multiple rounds of
storms. Some localized amounts of 1-2" are possible. Low
temperatures will remain mild, generally in the upper 60s to
lower 70s.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
Saturday: A complex upper level pattern will be in place with a
weak rex block setting up over the western United States and
wave breaking occurring across the eastern United States. By
Saturday morning, the mid-level low will be approaching from the
west with the core of the DCVA moving over the Midlands of
South Carolina. In the upper levels of the atmosphere, a 60 to
80 kt jet streak will center over central North Carolina south
to the Midlands/ Upstate of South Carolina. This places coastal
South Carolina perfectly centered in the RRQ of the upper level
jet streak with impressive upper level divergence overhead. Net
storm motion is from the southwest 10 - 20 kt with warm cloud
depth layers around 12.7 kft. This will support the potential
for numerous rounds of showers and thunderstorms with storms
likely being very efficient rainfall producers (1" to 2" an
hour). Area wide rainfall totals of 0.50" to 1.5" appears likely
with the potential for localized amounts of 3" to 5". Expect
high temperatures in the lower 80s.
Saturday night: Precipitation will come to an end as the upper
level jet streak nudges to the east with the vorticity advection
turning neutral. Expect mostly cloud skies with lows in the
upper 60s to lower 70s.
Sunday: A weak cold front will wash across the area Sunday
morning with the upper level jet streak that was off the South
Carolina coast amplifying and bending back west as a tropical
low pressure approaches the region from the south. As the jet
streak begins to bulge back to the west, the cold front will
also start to retreat as a warm front. Initially, most of the
region will be dry Sunday morning with showers and thunderstorms
increasing in coverage Sunday afternoon.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
A great amount of uncertainty exists in the long term as
tropical low pressure approaches from the south. Deterministic
models and ensembles continue to show an impressive amount of
spread with about half of the solutions depicting a SC/ NC
landfall (or stalling the system right near the SC coastline)
with the other half of solutions showing the system approaching
the SC coastline and then recurving out to sea. The uncertainty
comes from the strength of a mid-level ridge, the approach of
Hurricane Humberto, 94L, and the upper level trough axis. All of
these factors will shape the eventual track of 94L. The split
94L heading west or east is a symptom of how even small changes
in any one of the factors above can have a drastic change on the
eventual track.
Most Likely Scenario: Given everything mentioned above, the
most likely scenario appears that 94L will approach the
coastline Monday into Tuesday as a strong Tropical Storm or a
weak Hurricane. The system will then likely slow down and either
make landfall or stall just off of the SC coast Tuesday.
Potential Impacts: Surge is possible with this storm. Everyone
should also prepare to observe wind speeds for a high end
Tropical Storm or a low end Hurricane. This has the potential
to produce large tree damage, damage to some structures, and
scattered to areas of power outages. This track and potential
slow storm motion would bring the threat of heavy rainfall. The
time to prepare is now. All residents should review their
evacuation plans and have emergency kits ready to go.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
18Z TAFs: Radar indicates convection developing across our area
this afternoon. It is expected to continue into this evening and
overnight, then increase in both intensity and coverage around
daybreak Saturday. We have VCSH and SHRA in the TAFs to account
for the expected coverage and impacts. But amendments may be
needed to add flight restrictions based on radar trend.
Otherwise, MOS and the ensembles show MVFR developing late
tonight, then possibly dropping to IFR around daybreak
Saturday. We have MVFR during this time period, but wouldn`t be
surprised if it needs to be lowered further with future TAFs.
Extended Aviation Outlook:
Saturday: Multiple rounds of showers and thunderstorms are
possible with restrictions in visibilities and ceilings likely.
Sunday: VFR conditions will start in the morning hours as a
cold front moves across the TAF sites. Winds will back from the
northeast with mostly dry conditions early. By the afternoon, a
warm front will start to move onshore with winds veering around
from the southeast at all terminals. Multiple rounds of showers
and thunderstorms are possible in the afternoon and evening.
Some restrictions in ceilings and visibilities are possible.
Monday - Wednesday: Tropical low pressure is forecast to
approach the region from the south. Multiple periods of
visibility and ceiling restrictions are possible with winds
gusty and variable in direction.
&&
.MARINE...
Through Tonight: A cold front will approach from the west,
causing southerly winds around 10 kt this evening to back to the
SW overnight. Winds should ease just before daybreak Saturday.
Seas will average 2-3 ft.
Saturday - Sunday: Multiple rounds of showers and thunderstorms
are likely. Seas 2 to 4 ft increasing 3 to 5 ft by Sunday. A
cold front will briefly wash over the waters early Sunday with
winds turning from the northeast. Winds will then quickly veer
from the southeast as the front turns around and moves inland as
a warm front.
Monday - Wednesday: Tropical low pressure will approach the
waters from the south on Monday. A volatile sea state is likely
with wave heights above 10 ft possible. Winds could also be
above storm force with tropical headlines possible. Multiple
rounds of showers and thunderstorms.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
MARINE...None.
&&
$$
NEAR TERM...
SHORT TERM...
LONG TERM...
AVIATION...
MARINE...

NWS CHS Office Area Forecast Discussion