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Area Forecast Discussion (AFD)

Issued by Charleston, SC (CHS)

                            
000
FXUS62 KCHS 211802
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
202 PM EDT Thu Mar 21 2019

.SYNOPSIS...
A cold front will move into the region from the west late today
and then offshore tonight. High pressure will then build into
the region and persist through the weekend. Low pressure may
move through the Southeast on Tuesday. 

&&

.NEAR TERM /THROUGH TONIGHT/...
This Afternoon: The area will remain along the southern base of a 
mid-lvl trough of low pressure shifting over the Southeast United 
States, helping maintain a westerly flow across the area. The 
pattern will result in warmer conditions than the previous day as 
west-southwest sfc winds and a full sun occur in advance of a dry 
cold front that eventually passes through the area late afternoon 
into early evening. In general, high temps should approach the upper 
60s to lower 70s. Mixing profiles are also supportive of wind gusts 
as high as 15-25 mph during peak heating, highest across Southeast 
Georgia and coastal South Carolina where sfc temps are warmest this 
afternoon. 

Tonight: The cold front is expected to move offshore by early 
evening with the atmosphere too dry to expect any brief showers 
across northern SC zones. There should be a brief period of mid 
clouds then skies will become mostly clear. Low will be in the 40-45 
degree range and most all areas are expected to maintain a light WNW 
breeze overnight.

&&

.SHORT TERM /FRIDAY THROUGH SUNDAY/...
Strong continental high pressure centered over the Plains states 
Friday will move just north of the Southeast region Saturday, then 
offshore by late Sunday. It will bring our area dry conditions with 
mostly clear skies. Temperatures will be within a few degrees of 
normal.

&&

.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
High pressure will move offshore Sunday night. A coastal trough is 
expected to form Monday while a storm system approaches from the 
west. Models show the system moving through Monday night, then 
perhaps stalling along or just off our coast through Wednesday while 
high pressure prevails inland and to our north. Though, there 
remains uncertainty over the timing, strength, and the track of this 
system.

&&

.AVIATION /17Z THURSDAY THROUGH MONDAY/...
VFR conditions will prevail at both CHS and SAV terminals through 
18Z Friday. West-southwest winds could up to around 15-20 kt at 
both terminals this afternoon.

Extended Aviation: VFR through Sunday. There are low probabilities 
of flight restrictions due to an approaching storm system on Monday.

&&

.MARINE...
This Afternoon and Tonight: West-southwest winds will peak near 15-
20 kt at times this afternoon ahead of a dry cold front approaching 
the coastal waters late afternoon into early evening. Winds should 
be highest across northern South Carolina waters. Seas will generally
peak near 4-5 ft beyond 10 nm in nearshore waters and up to 4-6 ft
in offshore Georgia waters. Given the setup, a Small Craft Advisory
will remain in effect across offshore Georgia waters, even though
conditions should briefly improve offshore into the evening. Overnight,
jetting and surging offshore flow in the wake of the cold front will
likely support the continuation of a Small Craft Advisory across
offshore Georgia waters and potentially across all nearshore waters.
In general, west- northwest winds could gust as high as 20-25 kt
while seas build up to 5-7 ft, highest across offshore Georgia waters.

Extended Marine: High pressure will prevail across the region 
through the weekend. Low pressure may move through the Southeast on 
Monday.

Rip Currents: A moderate risk for rip currents continues today as 
lingering 2-3 ft swell energy occurs and southwest winds gust up to 
15-20 mph at times along the beaches, but conditions should begin
to improve late afternoon.

&&

.FIRE WEATHER...
A dry cold front will move into Southeast Georgia this afternoon.
Winds are expected to become gusty with 20-23 kt gusts forecast
for at least 2-3 hours. In addition, RH values will fall to near
critical values. Fuels in this region are the lowest in our forecast
area, but values appear marginal. Per collaboration with SPC 
Fire Weather, all of Southeast Georgia is in an elevated potential
for fire danger this afternoon. A Fire Danger Statement is in 
place for this region for anticipated afternoon conditions.

Friday: RH values as low as 25-30 percent and elevated offshore
winds could also cause fire concerns, especially if partners 
report low fuel moisture.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
MARINE...Small Craft Advisory until noon EDT Friday for AMZ374.

&&

$$
NEAR TERM...DPB
SHORT TERM...MS
LONG TERM...MS
AVIATION...DPB/MS
MARINE...DPB/MS
FIRE WEATHER...