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000
FXUS62 KCHS 290411
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
1211 AM EDT Thu Jul 29 2021

.SYNOPSIS...
High pressure will build over the area through Saturday,
bringing dry and hot conditions. A cold front will then stall
over the area Sunday through the middle of next week.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
The only meaningful changes made for the midnight update was to
introduce some low-end mentionable pops across interior portions
of Colleton, Dorchester and Berkeley Counties where a few
showers/tstms are being maintained along a southwestward moving
outflow boundary and to increase lows by several degrees in
Downtown Charleston. Patchy to areas of fog are expected to
develop across the interior through daybreak. The fog is likely
remain to remain fairly shallow given the marginal nature of the
1000 hPa condensation pressure deficit. Could see a few locally
dense spots that form so trends will be monitored for the
morning commute.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH SATURDAY/...
An upper ridge will expand to the east during the period,
bringing hot temperatures and mainly dry conditions. The warmest
temps are expected Friday through Saturday once a 15-20 kt
westerly flow develops at 850 mb. A somewhat drier airmass will
move in, with PWs at or below 1.75" most of the time. This,
combined with strong mid-level subsidence, will prevent
convection from developing Thursday and Friday. A slight
increase in moisture late Saturday, combined with a weak
shortwave, could spur a few showers and tstms to develop or move
in from the northwest.

The hot temps and heat indices are the main concern during the
period. Although far inland dewpoints should mix down to the low
70s each day, a fairly good sea breeze will surge dewpoints into
the mid/upper 70s across the eastern half of the area during the
afternoons. Temps forecast to reach the low to mid 90s Thursday
and mid/upper 90s Friday/Saturday. We`re currently showing heat
indices of 105-109F on Thursday with a significant area of
110-114F Friday and Saturday. A few areas closer to the coast
where hot temps intersect with particularly high dewpoints could
touch 115F at times Friday and Saturday. We will likely require
Heat Advisories for much of the area Friday and Saturday.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
An upper ridge will set up to our west late this weekend into
the middle of next week while a front stalls over the area. A
wet period is anticipated with numerous showers and tstms each
day, including during the overnight hours.

&&

.AVIATION /04Z THURSDAY THROUGH MONDAY/...
The 06z TAF discussion will be issued soon.

Extended Aviation Outlook: Flight restrictions are possible in
afternoon/evening showers and thunderstorms Saturday and Sunday.

&&

.MARINE...
Tonight: No significant changes to the previous forecast. Quiet
marine conditions will prevail with generally light and variable
winds of 5-10 knots or less. Seas will average 2-3 feet.

Thursday through Monday: Fairly persistent SW flow anticipated
Thursday through early next week. Winds could get close to Small
Craft criteria Friday afternoon due to a tightening gradient
ahead of a cold front. Winds along the coast each afternoon will
back slightly and strengthen with the sea breeze.

&&

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

&&

$$