544
FXUS62 KCHS 191722
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
122 PM EDT Thu Sep 19 2024

.SYNOPSIS...
Weak high pressure will develop over the region today. The area
of high pressure is expected to gradually strengthen through
early next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Mid level trough axis will remain near the Southeast coast
today. A weak pressure pattern resides at the surface. There
should be enough instability to help generate isolated to
scattered showers this afternoon, especially across South
Carolina. Thunder potential still looks pretty limited, so kept
mention out of the forecast for now. High temperatures look on
track to reach the mid to even upper 80s, warmest over southeast
Georgia.

Tonight: Any diurnally driven shower activity will fade this
evening with quiet conditions dominating. Some fog will again be
possible although with lower probabilities compared to this
morning. Lows back into the middle to upper 60s...warmer along
the coast.

&&

.SHORT TERM /FRIDAY THROUGH SUNDAY/...
Friday: The area of low pressure from Thursday will be just off of
the coast of New England with SC and GA falling on the convergent
side of the trough axis. This coupled with decreasing PWATs (down to
around 1.45") will keep the day precipitation free with surface high
pressure nudging in from the north. Expect high temperatures mostly
in the mid to upper 80s with low temperatures Friday night in the
mid to upper 60s.

Saturday: Mid-level high pressure centered over southeast Texas will
continue to elongate northeast allowing heights to rise across GA
and SC. PWATs due rise to around 1.6", but mid-level lapse rates
remain poor with an inversion in place around 800 mb. This will keep
the region dry.

&&

.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
Below normal precipitation and above normal temperatures are
forecast through the long term, with above average confidence for
this especially in the Sunday through Tuesday timeframe.

There have been several notable trends in the ensemble guidance over
the last couple of days, as a cornucopia of blocks persist across
the Northern Hemisphere. The main issue that ensemble guidance has
been trying to resolve the last couple of days is a Rex block that
is forecast to develop over northern Quebec. This then influences an
upper level low over the Canadian Maritimes and the southern
decaying weakness off of the Mid-Atlantic coast. The trend in the
ensemble guidance has been for the Rex Block to center further east
and allow the decaying weakness off of the Mid-Atlantic coast to
exit the region quicker. This further east Rex block also means that
temperatures and dewpoints continue to trend up for this weekend.

Sunday into Monday: Mid-level heights will start to rise across SC
and GA from a building 500 mb ridge. This will allow temperatures to
also increase into the upper 80s to low 90s inland. No precipitation
is expected as mid-level ridging builds and PWATs remain around 1.5".

Tuesday through Wednesday: 500 mb ridging looks to translate east
and center across the southeastern United States. As this occurs,
temperatures will remain seasonably warm, or above average, in the
upper 80s to low 90s. Mostly dry weather is expected, but afternoon
sea breeze convection can`t be completely ruled out as PWATs rise
towards 1.75".

&&

.AVIATION /18Z THURSDAY THROUGH MONDAY/...
Prevailing VFR conditions today. A brief shower is possible
this afternoon, but impacts in the way of flight restrictions
should be minimal if one occurs.

There is a chance for restrictions in fog late tonight towards
daybreak, with the best chances at KSAV. Maintained MVFR for
now.

Extended Aviation Outlook: VFR. No precipitation is expected.

&&

.MARINE...
Winds turn more easterly for the afternoon before becoming
northerly again late tonight. Winds generally remain 10 knots
or less with seas averaging 2 to 4 feet.

Friday: Northeast winds will slowly start to increase in speed 10 to
15 kt as surface high pressure builds in from the north. Wind gusts
of 15 to 20 kt possible, or below Small Craft Advisory criteria.
Seas 3 to 4 ft.

Saturday through Monday: Building high pressure will result in
northeast winds 10 to 15 kt with gusts 15 to 20 kt. Seas 3 to 4 ft.
Winds and seas should remain below advisory criteria.

&&

.TIDES/COASTAL FLOODING...
Positive tidal anomalies along with high astronomical tides from the
full moon will lead to elevated tides for the rest of this week and
through the weekend. Coastal Flood Advisories will probably be
needed for both the morning and evening high tides through Friday
for both Charleston Harbor and Fort Pulaski.

The astronomical high tides start to lower Saturday and Sunday, but
the morning high tides will likely be elevated enough to still
require Coastal Flood Advisories (especially for Charleston and
coastal Colleton Counties). More uncertainty exists for Fort
Pulaski.

&&

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

&&

$$

NEAR TERM...ETM
SHORT TERM...Haines
LONG TERM...Haines
AVIATION...ETM/Haines
MARINE...Adam/Haines