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000
FXUS62 KCHS 292238
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
638 PM EDT Thu Jul 29 2021

.SYNOPSIS...
High pressure will build over the area into Friday night. A
cold front will then stall over or just north of the area
through the middle of next week.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
Quiet weather will prevail tonight. Lingering cu will continue
to dissipate with loss of heating, resulting in clear skies
overnight. Can`t rule out some cirrus dropping in from the north
late tonight. Lows will average in the mid 70s, except upper
70s near the immediate coast. Ongoing forecast was in good
shape, so very little change was needed with the early evening
update.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...
Forecast confidence: Moderate.

Deep high pressure into Friday night across the SC Lowcountry/GA
Coastal Empire will give way to an approaching cold front by this
weekend. The main concern this period will be the potential for
excessive heat, which would really be the first time this year.

On Friday, the low-level flow will be more west-southwest and
ridging will be strongest which will limit the sea breeze influence
and overall risk for convection. Temperatures should push toward the
century mark inland with even coastal areas possibly touching 90
degrees. The biggest forecast challenge is dewpoint temperatures
which will likely lower inland during the day but surge near the
coast late. At this point we are forecasting heat indices peaking
close to 115 degrees just inland from the immediate coast and we
have thus issued an Excessive Heat Watch there with a Heat Advisory
for slightly lower heat indices for much of the rest of the
Lowcountry/Coastal Empire except for areas well inland toward the
CSRA where confidence is lowest in reaching heat indices of 110
degrees. Some shortwave energy could help spark a few showers/storms
Friday night, mainly in SC, although we left rain chances at about
10 percent or less for now due to low confidence. Lows Friday night
will be above normal in the mid to upper 70s most spots with lower
80s near the coast.

Saturday: The front looks to be closer to the area so despite a bit
more cloud cover to start it should be another hot day with highs in
the mid to upper 90s most inland spots, possibly touching 100
degrees, especially in GA. Heat indices could once again near 115
degrees in spots just inland from the beaches but should at least
reach Heat Advisory levels most areas. Some more shortwave energy
aloft and the pinned sea breeze could be enough to spark off
isolated to scattered showers/storms mostly later in the day. A few
of these storms could become severe. Storms will wind down later
Saturday night with lows mainly in the upper 70s inland.

Sunday: The pattern is about the same although the mid level
troughing is a bit weaker which should lead to a bit better rain
chances, especially later in the day once the sluggish sea breeze
gets going. Heat indices could once again reach 110 degrees for some
areas so additional Heat Advisories will be possible.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
Forecast confidence: Moderate.

Deep troughing should prevail keeping the weather more unsettled and
cooler than normal. Some periods of heavy rain are possible.

&&

.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
VFR.

Extended Aviation Outlook: High confidence in mostly VFR
conditions at KCHS/KJZI/KSAV through early Sunday afternoon
although some restrictions will be possible late Saturday due to
showers/storms. There looks to be a greater risk for restrictions
from periodic showers/storms starting Sunday night as deeper
moisture move into the area.

&&

.MARINE...
Tonight: South to southwest winds will pick up to 10-15 kt
overnight in response to lee-side troughing that develops well
to the west. Seas will average 1-2 ft.

Friday through Tuesday: Moderate confidence this period. Atlantic
high pressure will prevail with a stalled front inland. Winds could
get near Small Craft Advisory levels at times, especially Friday
afternoon/evening near the Charleston County coast.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...Excessive Heat Watch from Friday afternoon through Friday
     evening for GAZ117-119-139-141.
     Heat Advisory from 1 PM to 7 PM EDT Friday for GAZ101-116-118-
     137-138-140.
SC...Excessive Heat Watch from Friday afternoon through Friday
     evening for SCZ044-045-048>052.
     Heat Advisory from 1 PM to 7 PM EDT Friday for SCZ042-043-047.
MARINE...None.

&&

$$

NEAR TERM...ETM
SHORT TERM...RJB
LONG TERM...RJB
AVIATION...ETM/RJB
MARINE...JRL/RJB