584
FXUS62 KCAE 011034
AFDCAE

Area Forecast Discussion
National Weather Service Columbia SC
634 AM EDT Wed May 1 2024

.SYNOPSIS...
Dry and warm conditions expected Wednesday and Thursday as
surface high pressure and upper level ridging build back into
the area. Rain chances start to increase Friday as moisture
steadily increases as southwesterly low level flow strengthens.
Showers- storms are then likely over the weekend as a series of
weak disturbances push across the area and moisture continues
to build.

&&

.NEAR TERM /THROUGH TONIGHT/...
The upper level trough is moving east of the area early this
morning. There remains enough lift for a few isolated showers
mainly in the east Midlands mainly before dawn. Water vapor
imagery is showing dry air aloft spreading into the area from
the west. With shallow low-level moisture remaining and near
calm winds, expect areas of fog to develop toward morning,
possibly dense in some areas, especially the southern Midlands
and CSRA where model fog probabilities are higher. Will monitor
for possible advisory at some point. Surface and upper ridge
will be building in from the west this afternoon, the focus for
any showers should be mainly in the coastal plain where the
surface trough will be located as suggested by CAMS. So after
the fog lifts, expect clearing skies. Temperatures should be
warm, with guidance consistent in the low to mid 80s. Clear
tonight, perhaps some patchy fog toward morning with lows around
60.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
A quiet short term period is expected as deep ridging will build
across the SE CONUS. As the ridge axis starts settles overhead,
the dry northwesterly flow from 850-250mb will weaken and turn
more westerly, with the associated surface high pressure center
shifting offshore. Despite losing the downslope component flow,
PWAT`s overall will not increase much, but with the surface
high pressure center shifting east, easterly low level flow will
develop below 850mb. Dew points will tick up a bit compared to
Wednesday thanks to the onshore flow and clear skies will help
temps climb into the upper 80`s.

Offshore high pressure will strengthen further into Friday as
ridging continues to build aloft. Temps will again climb into
the upper 80`s but steadily increasing PWAT`s will yield some
mid-level cloud cover by the afternoon. Surface winds will turn
out of the south as the surface high strengthens. GEFS and EC
guidance suggests some showers pushing into the region by late
Friday as some weak troughs ride through the main ridge axis to
our northwest. Precip chances remain low however until
overnight Friday and into Saturday morning, as PWAT`s climb back
above 1.5".

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
Broad ridging over the SE CONUS will begin to weaken Saturday
while PWAT`s continue to increase with southerly component low
level advection strengthening. Troughing to our northwest will
flatten the ridge and provide the impetus for some shower-storm
activity each day through long term period; none of the mid-
level shortwaves will correspond with a strong enough low-level
boundary to scour out entrenched moisture. GEFS and EC ensemble
members clearly show this elevated period of moisture, with
mean PWAT`s up around 1.5-1.75" Saturday-Tuesday. So while PoPs
are relatively high each day, the severe potential will remain
limited over the weekend; CSU probs only show marginal risks
for Saturday and Monday. This is primarily due to mediocre low-
mid level lapse rates and a lack of height falls which only
yield ~500 J/kg ML CAPE each afternoon over the weekend. From a
shear perspective, as the ridge axis weakens, mid- level flow
aloft will also weaken resulting in 0-6km shear of less than
15-20 knots. Increasing surface heating and steepening lapse
rates in general are expected by Monday and Tuesday however;
GEFS > 1000 J/kg ML CAPE is > 50% both days. But shear will
remain fairly both days. So, showers and storms probable
Saturday through Monday afternoons with increasing severe
potential for Monday as instability ramps up.

&&

.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
LIFR/IFR conditions expected early this morning as fog and
stratus develops across the region.

Upper level trough moving east of the area early this morning.
Satellite showing clearing aloft behind the trough. With low
level moisture in place and near calm winds, expect areas of
stratus and fog. The latest nighttime microphysics satellite
product is showing stratus developing rapidly across the area
with a few areas reporting low visibility. Confidence is high
for LIFR/IFR conditions to develop before 12z. Low clouds and
fog should lift by 14z-15z with scattered cumulus. Winds will
shift to northwest to north behind the trough less than 10
knots.

EXTENDED AVIATION OUTLOOK...Some late night/early morning fog/
stratus possible. Increasing moisture, some upper energy, and a
surface boundary expected to provide a chance of showers and
thunderstorms, and associated restrictions, Fri thru Sun.

&&

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

&&

$$