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Area Forecast Discussion (AFD)

Issued by Charleston, SC (CHS)

                            
000
FXUS62 KCHS 201117
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
717 AM EDT Wed Mar 20 2019

.SYNOPSIS...
A surface trough will develop along the Carolina Coast today
then move away from the area tonight. High pressure will then
build into the region and persist through the weekend. Low
pressure could move through the Southeast Tuesday. 

&&

.NEAR TERM /THROUGH TONIGHT/...
Today: Model consensus has settled on a dry forecast across the
forecast area, although sky cover progs and resulting temperatures
remain on the tricky side with low pressure developing near the
nose of the offshore inverted trough. Moisture advection below 
500 MB is aimed at the lower NC coast and there is uncertainty 
on the coverage of stratocu over Southeast SC. The 00Z NAM continued
to show a very cool low level air mass with plenty of RH below 
850 MB at KCHS which was too much of an outlier to even consider
for today. We made little change to our forecast temp schemes. 
GA zones should see plenty of sunshine today and highs expected 
to warm to the mid/upper 60s this afternoon. 

Tonight: Weak low pressure is expected to lift north through Eastern
NC as a mid shift short wave shifts into the far Northwest GA late.
Dry weather is on tap with clouds across Eastern SC expected to 
clear as boundary layer flow goes offshore overnight. Lows will
range from the upper 30s well inland to the lower/mid 40s in the
coastal corridor.

&&

.SHORT TERM /THURSDAY THROUGH SATURDAY/...
Tranquil weather is expected. High pressure will build and then 
prevail across the region during the short term. Dry conditions are 
forecasted with mostly clear skies. Temperatures will be near normal 
for this time of year.

&&

.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
High pressure will prevail across the region through the weekend. 
Models show a coastal trough forming Monday while a system 
approaches from the west. The system could bring rainfall to the 
region on Tuesday. However, there remains uncertainty over the 
timing, strength, and the track of this system.

&&

.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
VFR. 

Extended Aviation: VFR.

&&

.MARINE...
Low pressure developing east of the South Carolina Coast today
will shift north of the waters tonight. Northeast flow will
mainly be below 20 kt today with winds backing more offshore
tonight with lighter speeds below 15 kt. Seas will remain in 
SCA ranges today and latest guidance was hinting some of our 
near-shore waters may fall below SCA criteria sooner by early 
tonight. If this occurs, we could cancel near shore advisories
a bit earlier than late tonight.

Extended Marine: High pressure building towards the region will 
allow winds and seas to trend downward. The Small Craft Advisory 
will expire for the GA waters beyond 20 nm on Friday. No advisories 
are expected during the weekend.

&&

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

&&

.TIDES/COASTAL FLOODING...
Astronomical factors and moderate northeast winds today will 
result in elevated tides with Coastal Flood Advisories in 
effect until mid morning for the entire coast as tides expected 
to approach moderate flooding, more likely remaining in more 
minor flooding ranges this morning. Another round of coastal 
flooding is possible again this evening. The risk of coastal 
flooding lowers on Thursday due to offshore winds.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...Coastal Flood Advisory until 10 AM EDT this morning for GAZ117-
     119-139-141.
SC...Coastal Flood Advisory until 10 AM EDT this morning for 
     SCZ048>051.
MARINE...Small Craft Advisory until 6 PM EDT this evening for AMZ352-
     354.
     Small Craft Advisory until 6 AM EDT Thursday for AMZ350.
     Small Craft Advisory until noon EDT Friday for AMZ374.

&&

$$
NEAR TERM...
SHORT TERM...
LONG TERM...
AVIATION...
MARINE...
FIRE WEATHER...
TIDES/COASTAL FLOODING...