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Area Forecast Discussion (AFD)

Issued by Charleston, SC (CHS)

FXUS62 KCHS 190410

Area Forecast Discussion
National Weather Service Charleston SC
1210 AM EDT Wed Jun 19 2019

A trough of low pressure will generally prevail into early next


Weakening convection will move across the northern portions of
Colleton, Dorchester and Berkeley Counties through 1-2 AM before
dissipating. Lows will range from the lower 70 inland to the
upper 70s at the beaches.


Lower confidence Wednesday with moderate confidence thereafter.
Deep layer troughing will prevail through Thursday night with 
less troughing aloft Friday. Some showers and weak thunderstorms
are expected Wednesday morning as an upper shortwave trough 
moves through although afternoon/early evening coverage is a bit
less certain given some drier air and subsidence behind the 
initial shortwave. We maintained 50 percent rain chances however
for now as another shortwave is expected to approach later in 
the day. Wednesday night should then be mainly dry with a better
chance of showers and storms Thursday afternoon/evening ahead 
of another much stronger shortwave. Stronger deep layer shear 
should lead to a slightly greater risk for a few severe storms, 
especially across areas farther inland. Drier air should then 
move in from the north Thursday night although lingering 
moisture could lead to some showers/storms still near the 
Altamaha River area mainly through Friday morning. 

Temperatures should be above normal through the period. Heat 
indices could be near early-season Advisory levels (105 degrees)
south of I- 16 near and to the west of I-95 Thursday and Friday


Saturday and Sunday: Lower chances for rainfall are expected as
the mid and upper level ridge holds over the region and deep 
layer moisture remains marginal. Overall, expect only isolated 
to scattered mainly afternoon and evening showers/thunderstorms.

Monday and Tuesday: Models are indicating that the upper ridge 
begins to break down as an upper level short wave trough moves 
across the northeast U.S. With Deep layer moisture on the rise, 
and lowering upper level heights, expect that overall chances 
for convection will gradually increase back toward more climo 
values of 30-40% levels.

The latest guidance continues to show temperatures well above 
normal through this period. Highs in the lower to mid 90s and 
lows in the lower to mid 70s.


VFR for much of the period. Scattered showers/tstms are expected
to develop by late morning across interior Southeast Georgia and
spread east/northeast to the coast. The greatest impact
probabilities look to occur at KSAV where a TEMPO group will
placed for MVFR conditions roughly 17-20z. At KCHS, guidance is
not as robust on coverage that far to the north, so no mention
of tstms will be included there for the 06Z TAF cycle. 

Extended Aviation Outlook: Periodic restrictions likely due to 
mainly afternoon and evening showers and thunderstorms through 
Thursday evening. Lower risk for impacts from mainly 
afternoon/evening showers and thunderstorms Friday through the 


Tonight: Southerly flow this evening will turn more 
southwesterly through the period. Modest surging is expected, 
and winds should top out around 15 knots. Seas will average 2-4 

Wednesday through Sunday: A trough will generally persist 
inland through the period, although a rare June cold front will 
likely move south into the SC waters Friday night/early 
Saturday. Breezy winds ahead of the front could lead to marginal
Small Craft Advisories, mainly just in Charleston Harbor 
Wednesday afternoon, then across the rest of the marine area at 
times through Thursday night. No other major concerns thereafter
through the weekend.