Area Forecast Discussion
Issued by NWS Columbia, SC

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FXUS62 KCAE 260219
AFDCAE

Area Forecast Discussion
National Weather Service Columbia SC
1019 PM EDT Tue Apr 25 2017

.SYNOPSIS...
Low pressure centered over Delmarva tonight will continue moving
northeastward. High pressure will ridge into the forecast area
from the Atlantic in the wake of this system Wednesday. A
cold front approaching from the west Thursday will become
diffuse Thursday night. Moisture associated with the front will
bring a chance of showers and thunderstorms Thursday and
Thursday night.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
Wrap-around low-level moisture associated with low pressure
over Delmarva will shift farther northeastward tonight and
expect clearing during the early morning hours. Lingering low-
level moisture and light wind may help support fog, but the fog
should be limited by dry air advection with h85 westerly flow
and a little mixing. SREF fog probabilities were low, and the
NAM and GFS MOS mainly showed light fog at a few sites. We
forecasted just patchy fog. The temperature guidance was close.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
Fair and warmer conditions are forecast Wednesday with upper
ridging. At the surface, developing southerly flow will also
support warm advection into the region. The progressive upper
trough will breakdown the upper ridge Thursday as a weak front
pushes into the forecast area Thursday night. Moderate moisture
advection with a 30- to 35-knot h85 southerly jet will move
into the region late Thursday and Thursday night ahead of the
front bringing much higher precipitable water air with values
around 1.6 of an inch. Will continue to carry low chance pops
mainly in the west section. The greater upper forcing will be
shifting north of the region and the loss of daytime heating
will limit the shower and thunderstorm chance. Temperatures
during this period will be well above normal with highs
generally in the mid to upper 80s and lows in the 60s.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
The boundary that pushed into the area Thursday night will
become diffuse Friday as the upper ridge over the western
Atlantic rebuilds over the Southeastern States. Surface high
pressure also centered over the western Atlantic will direct a
moist southerly flow into the area through the weekend creating
summerlike conditions with rising temperatures and humidities.
Yet another deep upper trough will develop over the Plains by
late Saturday with a cold front pushing eastward into the
forecast area late Sunday into Monday. Strong moisture
advection and precipitable water values pushing near 1.7
of an inch will support convection Sunday night and Monday so
will continue the mention of chance pops.

Temperatures through much of the extended period will be well
above normal with highs in the upper 80s to lower 90s and lows
in the 60s. Temperatures will be closer to normal with highs in
the 70s and lows in the 50s by Tuesday.

&&

.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
Wrap-around low-level moisture associated with low pressure
over Delmarva will shift farther northeastward tonight and
expect clearing during the early morning hours. Lingering low-
level moisture and light wind may help support fog, but the fog
should be limited by dry air advection with h85 westerly flow
and a little mixing. SREF fog probabilities were low, and the
NAM and GFS MOS mainly showed light fog at a few sites. We
forecasted TEMPO MVFR fog during the early morning hours except
increased moisture and cooling in the river valleys supported
IFR fog at AGS and OGB. Heating and mixing with dominate ridging
should result in VFR conditions after 13z. Followed the NAM and
GFS MOS for the wind forecast with light and variable tonight
and southwest about 6 knots after 13z.

EXTENDED AVIATION OUTLOOK...No significant impacts expected.

&&

.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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