Area Forecast Discussion
Issued by NWS Charleston, SC

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FXUS62 KCHS 131103

Area Forecast Discussion
National Weather Service Charleston SC
703 AM EDT Thu May 13 2021

High pressure will build into the area today and persist
through early next week.


As of 7 AM: KCLX indicated that sprinkles and light rain was
drifting over portions of SE GA. The forecast update will remove
the mention of drizzle. Otherwise, cloud breaks should widen
through the rest of the morning. Given the earlier cloud
erosion and MOS trends, highs were warmed by a degrees across

As of 420 AM: KCLX detected a few patches of light returns over the
forecast area, associated with drizzle. The drizzle is expected to
end before daybreak as dry air increases from the NW. Another batch
of weak returns was located over SE GA, drifting to the NE. This
activity appears associated with the approach of the entrance region
of a 120 kt jet, expected to pass over the CWA by mid-morning. These
two period of precipitation will be highlighted with SCHC PoPs this
morning. By this afternoon, sfc high pressure will build across the
forecast area and cloud cover should gradually dissipate from west
to east. Using a blend of MOS, high temperatures are forecast to
range around 70 degrees this afternoon. Sfc high pressure will
continue to increase across the Southeast U.S. tonight, supporting
steady NE sfc wind. Cool thicknesses and sparse cloud cover should
result in another morning of below normal temperatures. Low
temperatures are forecast to range from the upper 40s inland to the
mid 50s along the coast.


High pressure and drier will continue to build south into the area
on Friday and then prevail through the weekend. The area will be
rain-free with plenty of sunshine through the weekend. A gradual
warming trend will occur as heights rise aloft and low-level
thicknesses increase. High temps will be in the 70s Friday and
Saturday, then mid 70s to low 80s on Sunday. Low temperatures will
be in the upper 40s to low 50s inland with mid 50s to low 60s along
the coast on Friday night. Then, Saturday night will be a few
degrees warmer.


Low temperatures overnight Sunday will be in the mid 50s inland and
upper 50s to mid 60s along the coast. Then on Monday, there are
indications that the prevailing high pressure could weaken and move
away from the area which would allow for deep moisture to move back
into the area. Cloud cover will likely increase on Monday and then
rain chances pop back up in the forecast for each of the following
days, mainly in the afternoon. Although, have kept POPs and
thunderstorms at slight chance due to uncertainties in the models.
Temperatures will see a gradual warming trend and by mid-week, high
temps will be solidly back in the 80s. Lows will be in the 60s with
low 70s along the coast.


Prior to the 12Z TAFs, IR satellite indicated that the clearing
line was located generally over the Coastal Plains with high
clouds extending west to the Fall Line of SC and GA. Based on
the satellite trends, ceilings and patchy sprinkles may linger
over the KSAV until 14Z. The rest of the period should feature
steady NE winds and VFR conditions.

Extended Aviation Outlook: VFR will prevail.


Today and tonight: The marine zones will remain between a weak low
over the Gulf Stream and high pressure centered over the Mid West.
The sfc high is forecast to gradually increase across the forecast
area today and tonight, resulting in a 2-3 mb pressure gradient
through the near term. The pressure pattern should support gusty NE
winds off the coast, with gusts between 25-30 kts. Seas will
generally persist between 4-7 ft. Small Craft Advisories are in
effect outside the Charleston Harbor.

Friday through Tuesday: As high pressure builds into the region on
Friday, the pressure gradient will remain somewhat pinched as a
stationary front moves much further south of the area. Small Craft
Advisories for SC/Charleston county/Georgia nearshore waters out to
20 nm will remain in effect through late Friday, mainly for seas
over 6 feet. Though, could see occasional wind gusts to 25 knots.
For the outer Georgia waters, 20-60 nm, seas are expected to remain
over 6 feet through Saturday afternoon so an SCA will remain in
effect until then with winds occasionally gusting to 25 knots on
Friday. By late Saturday, ideal marine conditions should return
and last through early week.

Rip currents: An elevated risk of rip currents is possible through
late week due to gusty northeast winds.


An unseasonably cool air mass, accompanied by clouds and light
rain, could challenge the following record low maximum
temperatures today, 5/13.

5/13 68 (1996)

5/13 68 (1996)

5/13 69 (1928)


MARINE...Small Craft Advisory until 10 PM EDT Friday for AMZ350-352-354.
     Small Craft Advisory until 5 PM EDT Saturday for AMZ374.



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