994
FXUS62 KCAE 020809
AFDCAE

Area Forecast Discussion
National Weather Service Columbia SC
409 AM EDT Thu May 2 2024

.SYNOPSIS...
Upper ridging and surface high pressure will continue to build
back into the region Thursday with high temps pushing 90F. Much
the same expected for Friday before rain chances steadily
increase late Friday evening into Saturday. Deep moisture
convergence coinciding with an upper level trough will drive
widespread showers and isolated thunderstorms Saturday.
Lingering moisture and little changes aloft will yield further
shower-storm chances Sunday through Wednesday.

&&

.NEAR TERM /THROUGH TONIGHT/...
The sea breeze boundary has pushed into the central Midlands and
dew points are higher east of CAE and AGS. Dense fog is
developing in the southeast Midlands and went ahead and issued a
dense fog advisory for that region. Will monitor satellite and
observations for possible extension of the advisory inland
toward CAE. The threat currently looks lower in the CSRA where
the air mass is noticeably a little drier. After the fog lifts
by 1000 am, surface ridge centered off the coast and upper ridge
will be building across the area. Boundary layer temperatures
this afternoon are a few degrees warmer than yesterday and
soundings show subsidence inversion. Low level flow will be more
southeast this afternoon which could keep temps down slightly
given maritime influence, but think highs around CAE and AGS
will be around 90 degrees. So went slightly above the NBM and
overall consensus guidance for highs. Little change in the air
mass tonight, so clear skies with maybe some patchy early
morning fog. Lows mainly in the low 60s although slightly cooler
in the SC Piedmont.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
Mid-upper level ridging will begin to flatten out Friday as a
series of shortwaves push through the ridge axis. Offshore
surface ridging will consequently weaken slightly, but will
shift far enough east to allow southwesterly to develop below
500mb. Moisture advection will be fairly slow however, keeping
PWAT`s stuck around 1.0" through later Friday and thus keep
precip chances low until late Friday evening; hi-res guidance
and global deterministic push the vast majority of resolved
diurnal precip into the extreme western CSRA and Upstate.
Sufficient moisture convergence for scattered precip in the CSRA
and Midlands will arrive overnight Friday and Saturday morning
with PWAT`s jumping over 1.5" as a sharper 500-250mb trough
slides into AL-GA. The poor diurnal timing with this initial
moisture surge should prevent much in the way of thunderstorm
activity but some scattered showers will likely develop.
Diurnal heating, the approaching shortwave aloft, and strong
moisture convergence with PWAT`s over 1.75" will yield
widespread showers and storms Saturday afternoon. Thunderstorm
activity will likely remain weak however as only modest
instability will develop with meager mid-level lapse rates and
cloud cover; GEFS prob of > 500 J/kg is ~80% for most of the
area, but > 1000 J/kg is only 10-20%. Organized convection is
also not expected as very weak mid-level flow will only muster
0-6km shear of 10-15 knots.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
A summer-like pattern is expected to develop as we move late in
the weekend and into next week with broad ridging remaining
across the SE CONUS. NAEFS highlights this period pretty clearly
with slightly above average heights, temps, and PWAT`s yielding
a favorable setup climatologically for diurnal shower-storms
each day. While the ridge will remain anchored aloft, some
shortwaves associated with a deep trough over the north-
central CONUS will provide some further focus for lift and
precip chances, especially on Monday, with the conditional
unstable airmass lingering. GEFS and ECE steadily increase
instability each afternoon as the airmass steadily warms with
southwest low- level flow expected to continue; probs of > 1000
J/kg are over 50% by Monday. Towards the end of the longer term
period and into late next week, well above average temps are
expected to develop; there is increasing potential for high
temps in the low- mid 90`s (10-15 degrees above average) as GEFS
and EC members come into tighter agreement.


&&

.AVIATION /07Z THURSDAY THROUGH MONDAY/...
Restrictions in fog possible toward morning. Highest probability
at OGB.

Pressure ridge across the area. Mainly clear sky at 06z other
than some very thin high clouds in east central GA. Slightly
drier air from north Ga into the CSRA near the AGS/DNL
terminals. A sea breeze front has moved into central SC and dew
points have come up a bit from OGB to CAE. Some patchy fog
possible toward morning with shallow low-level moisture in
place/near calm winds, especially across eastern SC. Cross-over
temps from yesterday were relatively low but sea breeze front
may be contribute to more of a fog threat. The latest Lamp
guidance has decreased the threat at CAE and AGS areas, but
suggests a higher probability at OGB. Will go with MVFR fog at
CAE and AGS area terminals near 12z with the possibility of IFR
for a brief period at CAE and CUB. LIFR visibility at OGB. After
the fog lifts, expect scattered cumulus in the afternoon
especially in eastern SC associated with sea breeze. Winds light
and variable early then favoring southeast 5 to 10 knots in the
afternoon.

EXTENDED AVIATION OUTLOOK...Late night/early morning fog and stratus
possible through the period. Increased potential for showers and
thunderstorms Friday afternoon through Monday.

&&

.CAE WATCHES/WARNINGS/ADVISORIES...
SC...Dense Fog Advisory until 10 AM EDT this morning for SCZ037-038-
     041-135>137.
GA...None.

&&

$$