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000
FXUS62 KCHS 300410
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
1210 AM EDT Fri Jul 30 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 THIS MORNING/...
No major changes were made for the midnight update. Did increase
lows in Downtown Charleston by several degrees.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH SUNDAY/...
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 the rest of the Lowcountry/Coastal
Empire. 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/...
Deep troughing should prevail keeping the weather more
unsettled and cooler than normal. Some periods of heavy rain are
possible.

&&

.AVIATION /04Z 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...Heat Advisory from 1 PM this afternoon to 7 PM EDT this
     evening for GAZ087-088-099>101-114>116-118-137-138-140.
     Excessive Heat Watch from this afternoon through this evening
     for GAZ117-119-139-141.
SC...Heat Advisory from 1 PM this afternoon to 7 PM EDT this
     evening for SCZ040-042-043-047.
     Excessive Heat Watch from this afternoon through this evening
     for SCZ044-045-048>052.
MARINE...None.

&&

$$