Area Forecast Discussion
Issued by NWS Columbia, SC

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FXUS62 KCAE 181845
AFDCAE

Area Forecast Discussion
National Weather Service Columbia SC
245 PM EDT Wed Jul 18 2018

.SYNOPSIS...
A weak front will remain nearly stationary across east central
Ga and coastal SC for the next couple of days. The front will
provide focus for scattered afternoon and evening showers and
thunderstorms mainly near the front. In addition, a weak wave
of low pressure will move NE along the stalled front Friday and
provide a chance of showers and thunderstorms favoring southern
and eastern areas. An upper trough and surface boundary, along
with increasing atmospheric moisture, will lead to increasing
chances of showers and thunderstorms throughout the region
Saturday and possibly into Sunday. Some drier air may enter the
region early next week and reduce overall rain chances, although
some uncertainty exists.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
The frontal boundary has moved into the southern portion of the
CWA at 16z with some drier air filtering into the north Midlands
where dew points are now in the low to mid 60s. Satellite
showing cumulus developing vertically mainly in the southeast
Midlands and CSRA near the front. Air mass expected to be
moderately unstable late this afternoon through the evening near
the front. Little in the way of upper level forcing but still
expect scattered showers and thunderstorms near the front into
the early evening. Main threat heavy rain with precipitable
water near 2 inches. The latest HRRR suggest some convection
possible in the Upstate this evening which could move into the
north Midlands as suggested by Nam and GFS. But bulk of high
resolution models favors the southeast and expect air mass to
be a little drier in that region so only raised the pop slightly
there from previous forecast.

Temperatures will be near normal in the lower to mid 90s through
the afternoon. Although a little drier north of the front the
southern portion of the region will remain quite humid. Lows
tonight in the low to mid 70s.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
The front will slip a little farther to the south Thursday,
with drier air continuing to filter into the northern and
central forecast area. Little in the way of upper energy is
indicated Thursday as our region appears to be in a weak upper
ridge regime in between upper troughiness offshore and an upper
trough moving east into the Mississippi Valley. Best moisture
is still expected to remain across the CSRA and southern
Midlands where thunderstorms will become likely during the
afternoon and evening. The next trough will move in on Friday,
with upper energy moving northeast from the Gulf coast towards
the South Carolina coast along a stalled front. The best
thunderstorm chances will be in association with this feature,
impacting southern and eastern portions of the forecast area.
Severe threat is low both days but instability will be marginal
shear is increasing, especially going into Friday. However, at
this time the biggest threat is still locally heavy rain.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
The upper trough and its associated closed low will dig into
the region Saturday through Tuesday, with another reinforcing
trough approaching Wednesday. Instability will be high on
Saturday and bulk shear will be between 30 and 40 kts. The
models show a shortwave rotating around the low and moving into
the local area during the evening. This is beyond the point of
greatest instability, but strong to severe storms may still be
possible. The low will cutoff over the Tennessee Valley on
Sunday, and continue to sag south on Monday, stalling out on
Tuesday and Wednesday. This will allow moist southerly flow to
persist. Depending on the exact position of this low and
embedded shortwaves, a chance of thunderstorms could persist
throughout the period.

&&

.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
Generally VFR conditions expected through the 24hr TAF forecast
period, except near any thunderstorms through early evening.

Weak cold front becoming stationary near the AGS-OGB line.
line...although it may push a little further south through 00z.
Scattered cumulus developing across the area with some higher
mid level clouds. Scattered showers and thunderstorms expected
to develop near the front in moderately unstable air mass.
Continued VCTS forecast near the front and will monitor for
convective development and trends. Winds have shifted northeast
behind the front and remain light and variable in the CSRA.

Some patchy fog or stratus possible late tonight mainly near the
front so included lower clouds and MVFR conditions at AGS and
OGB based on LAMP.

&&

.CAE WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.

&&

$$
SYNOPSIS...99
NEAR TERM...99
SHORT TERM...99
LONG TERM...99
AVIATION...99


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