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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS62 KCHS 242317
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
717 PM EDT Sat Oct 24 2020

.SYNOPSIS...
High pressure will prevail today before an upper disturbance
passes through tonight. A weak cold front will then move
through Sunday night, followed by high pressure. A storm system
is expected to bring impacts to the region late next week.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
For the early evening update we have increased cloud cover based
on satellite trends that show those thicker clouds starting to
penetrate into our far interior Georgia zones. Additionally, the
upstream showers are making steady progress toward the
northeast, so we did raise PoP a bit for the mid and late
evening across our Georgia counties. Overnight the convection
will come at us from off the ocean with isentropic ascent, and
also in association with the short wave from the west and
southwest. We may need to raise PoP more in subsequent updates.

Temps will be far above climo, and we will be close to record
high min temps at all three climate sites for October 25.

Previous discussion...
A potent shortwave currently moving into western GA will move
into central and eastern SC overnight. Decent upper level
divergence will accompany the feature while unseasonably high
PWs of 1.8" will overspread the area. Scattered to numerous
showers will move in from the southwest late this evening and
spread into southern SC after midnight. The best upper forcing
will remain across our northwestern tier of zones closer to the
shortwave where upwards of a quarter inch of QPF are possible by
daybreak Sunday. Isolated thunderstorms are possible far inland
as well as over the coastal waters. Increasing clouds and weak
southerly flow will yield mild temps overnight with lows in the
upper 60s to lower 70s.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/...
Sunday: A mid-level short wave will lift from south to north
across the forecast area on Sunday. HREF indicates that a ragged
band of showers and isolated thunderstorms will likely cover
the CWA by daybreak, then exiting north through the daylight
hours. Using the HREF for the timing and placement, PoPs will
fall to 20-30 percent by 18Z, then falling below mentionable
levels by Sunday evening. As the convection tracks to the north,
partly sunny conditions should develop in the wake. High
temperatures are expected to range from the upper 70s across the
SC Lowcountry to the low to mid 80s across SE GA.

Monday and Tuesday: The center of a strong H5 ridge is forecast to
slide from N. FL to the western Atlantic, with 590 DM heights
remaining over the CWA. At the sfc, the pattern will feature high
pressure ridged over the western Carolinas with a trough over the
Gulf Stream. Conditions appear dry on Monday, with isolated showers
possible on Tuesday. Temperatures should slow warm trough the
period. By Tuesday, high temperatures are forecast to generally
range from the low to mid 80s.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
The mid-levels will consist of high pressure centered roughly over
FL Tuesday night. The high will slowly trend eastward, into the
Atlantic through Thursday. Meanwhile, a strong trough will approach
from the west on Thursday, then pass overhead or just to our north
on Friday. A cold front approaching from the west and a storm system
developing in the Gulf of Mexico could combine mid to late week to
bring various impacts to our area.

&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
Conditions favor the development of light to perhaps moderate
rains for several hours overnight and at least Sunday morning,
along with a low end potential for TSRA. Short wave energy will
sweep through around 06-15Z Sunday, while weak low level
forcing occurs from off the Atlantic due to the formation of a
subtle coastal trough.

At KSAV we have mostly low end VFR weather, but we are showing a
tempo for MVFR conditions from 09-13Z Sunday, as per the High-
Resolution guidance. Keep in mind that a larger window of MVFR
is certainly possible though.

We kept mainly low-end VFR conditions at KCHS, although we
can`t rule out a period of MVFR conditions from around 09-15Z
Sunday.

Extended Aviation Outlook: Restrictive ceilings and fog may develop
across the terminals around dawn Monday and Tuesday. A storm system
could bring more flight restrictions starting on Wednesday.

&&

.MARINE...
Fairly weak winds expected tonight due to weak high pressure
offshore. Seas over the offshore GA waters should drop below 6
ft by late tonight, after which the Small Craft Advisory for
those waters will drop off.

Sunday through Thursday: Swell associated with distant Hurricane
Epsilon will subside early next week. Conditions across the marine
waters are forecast to remain below Small Craft Advisory levels
through the period. Generally, winds are expected to remain below 15
kts with seas between 2-4 ft.

Rip Currents: Long period swells from distant tropical cyclone
Epsilon will continue to arrive on Sunday. An elevated risk for rip
currents will remain along the SC/GA coast. Swells are expected
to decrease by Monday.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
MARINE...Small Craft Advisory until 6 AM EDT Sunday for AMZ374.

&&

$$

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