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000
FXUS62 KCAE 172356
AFDCAE

Area Forecast Discussion
National Weather Service Columbia SC
756 PM EDT Wed Apr 17 2024

.SYNOPSIS...
High pressure will remain over the area Thursday with dry and
above normal temperatures expected. Moisture will increase
Friday and Saturday as a cold front moves into the area. With
strong heating, diurnally driven showers and thunderstorms will
develop. The front will become stationary near or slightly south
of the area Sunday. Deep moisture and lift across the area will
result in numerous showers Sunday through early Monday.
Temperatures Sunday and Monday are expected to be well below
normal.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
An upper ridge is forecast to continue to flatten through
tonight while an upper trough over the Midwest passes to our
north. Some embedded shortwaves within the flow between these
two features are expected to produce some enhanced vorticity
maxima. As these move through tonight, there is a slight chance
of light rain or sprinkles this evening. Overnight temps are
expected to remain warm due to the cloud cover and lows are
forecast to be in the lower to mid 60s.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
Thursday and Thursday night...Deep vertically stacked mature
cyclone over south central Canada with trailing south across the
Midwest. High pressure offshore of the Carolinas extending into
the area. A short wave trough will be moving southeast of the
area early in the morning. Ridge aloft appears flat through the
day but upper heights do rise a bit. Moisture decreases a tad,
with precipitable water generally less than 1 inch except for
the southeast Midlands/CSRA regions. Soundings indicate
subsidence, downslope flow early then weakening. With strong
diabatic heating temperatures will rise to near 90 degrees in
the afternoon, well above normal, actually near the record value
at AGS. Stayed close to the NBM guidance which is a little
below the record of 91 at AGS set way back in 1896. The upper
ridge weakens Thursday night and a short wave trough may move
through overnight from the Deep South. A few showers may be east
through Georgia late but think any rain should remain west of
the area. Guidance lows consistent in the low to mid 60s.

Friday and Friday night...Upper level ridge axis shifts off the
coast. The Main cold front appears to remain northwest of the
area across the western Carolinas/Mountains. Weak trough across
the area. The air mass is expected to be more moist with
precipitable water around 1.5 inches. Weak short wave troughs
may provide lift in the afternoon. Moderate instability possible
with relatively strong diabatic heating/ warm advection and
moisture flux with increasing southwest-west low level flow. SPC
has area in marginal risk, the deep layer shear is not overly
impressive. Max temps maybe a degree cooler than Thursday but
similar. Persistence with overnight lows.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
Good agreement in the Ensembles and deterministic models with
upper trough amplifying in the Ohio Valley and northeast
CONUS. This should send the main cold front into the area
Saturday. Scattered mainly diurnally driven showers and
thunderstorms again but noticed possibly weaker dynamics.
Strongest potential for strong storms will be across the CSRA
and southeast Midlands where the probability of CAPE > 500 will
be highest. Moderate instability possible in those region but
overall instability not impressive. Deep layer shear also
remains lacking. The front will be moving south of the area
Sunday.moves south or near the southeast Midlands Sunday. Upper
trough in the central and southern Plains moving toward the
Mississippi Valley Sunday. The front should move south of the
area. Deep moisture develops across the area with a weak coastal
low. Weak ridge building in from the north. This appears to be
an in-situ wedge set up and confidence is increasing for below
normal temps Sunday and Monday. Models suggest strong isentropic
lift and moisture flux with resulting showers and maybe an
isolated thunderstorm near the boundary. Used the 25th
percentile of the NBM for max temps which is more in line with
the latest ECMWF and GFS guidance. So highs mainly in the 60s
north and central and low 70s south. The moisture may linger
into MOnday as the upper trough remain west of the area, but the
NBM pop guidance is low by 12z Monday. Dry high pressure over
the area Tuesday with temperatures warming but still below
normal.

&&

.AVIATION /00Z THURSDAY THROUGH MONDAY/...
VFR conditions through the TAF period.

Satellite imagery and surface obs show extensive mid and high
clouds over the region as a weak disturbance moves toward the
TAF sites with WSR-88D network showing showers diminishing
quickly in the Upstate. Smoke has generally dissipated across
the area with what remains not impacting visibility. Over the
next couple of hours the winds will subside and become light and
variable as some remaining low clouds move into the terminals.
The potential for any remaining showers is too low to include
attm. The weak boundary will move east of the area around
daybreak with winds becoming westerly around 7 knots from mid
morning through the end of the period.

EXTENDED AVIATION OUTLOOK...No significant impacts to aviation
expected through Monday.

&&

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

&&

$$