Area Forecast Discussion
Issued by NWS Columbia, SC

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621
FXUS62 KCAE 142343
AFDCAE

Area Forecast Discussion
National Weather Service Columbia SC
643 PM EST Fri Dec 14 2018

.SYNOPSIS...
A warm front near the south part of the forecast area through
this evening will lift north of the area overnight. Associated
low pressure centered in the Lower Mississippi River Valley will
be in the Southern Appalachians Saturday and near the mid-
Atlantic Coast Sunday. A dry pressure ridge will dominate Monday
through Wednesday.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
Isentropic lift combined with a difluent upper pattern will
lead to continued rain through the evening. A warm front was
located over central SC with temps in the upper 50s and lower
60s east. Expect areas of fog especially near the warm front.
Wedge conditions continued farther west across the western
Midlands and Piedmont with temps in the mid 40s to around 50.

Observation trends and the high-resolution models indicate the
bulk of the higher rainfall rates will stay east of the forecast
area. The threat of excessive rain has diminished. However,
periods of rain on saturated soils could possibly lead to minor
localized flooding. The models indicate isentropic downglide
developing late tonight. Mid-level dry slotting will also near
the area. Still expect rain to diminish late tonight.

Should see little change in temperature with overnight lows
ranging from the mid 40s west to around 60 east.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
A closed upper level low will ride by to our north, while surface
low pressure moves off to our NE.  Dry air aloft will work into the
region from west to east during the first half of the day Saturday,
reducing most of the widespread rain coverage.  Modified Pacific
airmass and SW flow surface and aloft Saturday will provide for
warmer temps, and some scattered diurnal showers possible during the
day. Fair and not quite as warm Sunday, as low pressure to our NE
intensifies and high pressure shifts into the central CONUS.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
Modified Canadian high pressure center will shift SE into the Mid
Atlantic, providing continued fair weather but with some cooler, but
near normal, temps.  Main question involves late week time period.
Southern stream upper energy to move east across Mexico and into the
Gulf of Mexico, while northern stream troughiness digs into the E
CONUS. 00Z operational EC appears to phase the two systems,
resulting in a deep upper trough that brings moisture and a surface
wave NE into our region from the Gulf, though EC ensemble mean
appears to keep most of the QPF to our south and east. 00/06/12Z
operational GFS runs keep the two systems separate and suppresses
the moisture from the southern stream system to our south, though
00Z GFS ensemble mean does indicate some precip potential. All in
all, will utilize a model blend, providing slight chance to chance
POPs, also in line with ongoing forecast, for Thu/Fri. Guidance
consensus indicates temps generally near or just above climo thru
most of the period.

&&

.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
IFR conditions will generally persist through most of the TAF
period. Low-level wind shear will be an issue through the
evening.

A warm front in the region will likely remain south of the area
until morning, with wedge conditions maintaining widespread IFR
ceilings. May improve to MVFR mid to late morning, and then IFR
around 18Z as the front lifts north of the area. However, there
is high uncertainty in visibility, and conditions will be
variable through the night as another round of moderate showers
is expected. These showers should move out between 10Z and 11Z,
after which LIFR visibilities will be more likely.

Model guidance and pilot reports continue to indicate light to
moderate low- level wind shear this evening.

EXTENDED AVIATION OUTLOOK...Areas of MVFR or IFR may continue
through Saturday night associated with low pressure just north
of the area. Improvement may occur Sunday with the system moving
farther northeast of the area. Dry ridging will likely dominate
Monday through Tuesday.

&&

.HYDROLOGY...
Runoff from recent significant rainfall locally and upstream, along
with additional moisture from upstream snow melt, expected to result
in continued river flooding.

Latest river stages, forecasts, and warnings are available at our
web site at weather.gov/cae.

&&

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

&&

$$



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