Area Forecast Discussion
Issued by NWS Charleston, SC
FXUS62 KCHS 202009
Area Forecast Discussion
National Weather Service Charleston SC
409 PM EDT Thu Oct 20 2016
A mainly dry cold front will move through Friday with another
reinforcing dry cold front Monday night. Otherwise high pressure
will persist into the middle of next week.
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
A pattern change will begin overnight as ridging aloft begins to
give way to a digging shortwave moving from the Great Plains to
the Mississippi Valley. The forecast area will remain within the
warm sector of an approaching cold front, but with a relaxed
gradient in the area and no significant warm air advection to
encourage any cloud development, at least through the late night
hours, we should decouple and cool similar to the past couple of
nights. Conditions will once again favor patchy, dense ground fog
development for mainly low lying areas near bodies of water after
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...
Warmer than normal temperatures expected to persist into Friday
before a strong cold front moves through the area. Moisture appears
limited so do not anticipate significant rainfall but a few showers
will be possible, especially across SC. Temperatures will likely
fall during the day with winds picking up from the northwest after
the frontal passage, especially across inland areas. Many areas away
from the coast should reach the mid/upper 40s Saturday morning, then
only reach near 70 Saturday afternoon. Even cooler weather is likely
Saturday night when better radiational cooling conditions are
expected, with temperatures falling close to 40 well inland. Sunday
afternoon should see temperatures a bit warmer than Saturday as the
air mass modifies, likely reaching the lower to mid 70s most
locales, warmest in GA.
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
Cool and dry high pressure will remain over the Southeast Sunday
night, resulting in lows dipping into the upper 40s inland and
mid/upper 50s near the coast. By Monday, a large ridge of high
pressure will expand over the Deep South and Southeast states,
causing temps to return to the mid/upper 70s Monday afternoon.
Overnight lows will also be slightly warmer than previous nights,
ranging in the lower 50s inland to upper 50s/lower 60s near the
A dry cold front should approach from the north on Tuesday, leading
to slightly cooler afternoon temps in the mid 70s. On Wednesday,
cooler high pressure should build over the area from the north,
producing cooler conditions within a north/northeast flow regime. In
general, high temps should peak in the lower 70s in Southeast South
Carolina and low/mid 70s in Southeast Georgia. High pressure should
then begin sliding offshore Thursday, allowing a light onshore wind
develop over the Southeast. The change in flow will allow temps to
become slightly warmer than the previous day, peaking in the
mid/upper 70s for most areas away from the immediate coastline. A
few showers could also drift onshore, but should mostly remain east
.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
VFR will persist through at least this evening. At KSAV, high
pressure building along the Gulf Coast could create just enough
wind above the nocturnal inversion to mix down at times and
inhibit significant fog formation, so VFR forecast the entire
night. Synoptic flow will be lighter at KCHS, so MVFR visibilities
introduced for the late night/early morning hours as patchy fog
will likely form in the area. Both sites will be VFR post- sunrise
Friday, with only scattered cumulus and relatively light winds
ahead of an approaching cold front.
Extended Aviation Outlook: VFR conditions will prevail at KCHS/SAV
Friday night through Tue.
Tonight: Winds will remain around 10 kt or less overnight as the
ridge axis shifts offshore. Seas will average 2-3 ft nearshore
waters with 3-5 ft offshore waters.
Friday through Tuesday: No significant concerns expected until later
Friday after a strong cold front moves through. Advisory conditions
likely for all waters, except possibly Charleston Harbor, into
Saturday. Improving conditions then expected into early next week as
high pressure moves over the area causing a weakening of the cold
air advection and pressure gradient.
The NOAA Weather Radio transmitter in Cross, SC, transmitting on a
frequency of 162.475 MHz, is currently off the air due to phone
line problems. Actions are being taken to restore broadcasts, but
a restoration time is unknown.
MARINE...Small Craft Advisory from 5 PM Friday to noon EDT Saturday for