703
FXUS62 KCAE 181821
AFDCAE

Area Forecast Discussion
National Weather Service Columbia SC
221 PM EDT Fri Apr 18 2025

.SYNOPSIS...
Upper ridging will be in control of our weather through
the weekend, leading to continued dry weather with above normal
temperatures. The next chance of rain comes Monday night into
Tuesday from a cold front which could stall out across the
region for the middle of next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Key Message(s):

- High pressure persists with mild overnight temperatures.

An upper level ridge axis will continue to build over the
region through tonight, as surface high pressure prevails over
the western Atlantic.

Southerly flow has allowed Atlantic moisture to advect inland,
resulting in some diurnal cumulus clouds this afternoon,
with the greatest coverage closer to the coastal plain. These
clouds should quickly dissipate with the loss of daytime
heating. Highs this afternoon should reach into the lower and
mid 80s.

Moisture will get trapped beneath an inversion tonight, allowing
for some lower stratus clouds to develop. Fog could be patchy
in a few prone locations, but for the most part winds appear to
remain high enough to prevent any significant visibility issues.
Temperatures will be mild, with lows in the upper 50s to around
60.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
Key Message(s):

- Dry weather continues, with above normal afternoon highs both
 days

Strong ridging aloft is forecast to further establish itself over
the region on Saturday and Sunday. Ensembles and operational models
are in good agreement on a deep upper low over the intermountain
west continuing to slowly dig and shift eastward through the period.
This should modulate downstream ridging across the southeastern US,
with 500 hPa heights forecast to reach heights rarely seen in April.
A large, 591dm 500 hPa ridge is near or above the max value for the
climatological database this time of year per NAEFS, with heights 2-
2.5 SD above normal in the GEFS and ECE guidance. LREF soundings, as
well as BUFKIT soundings, reveal a strong subsidence inversion set
up across the forecast area both days, keeping the weather fairly
benign. NBM deterministic Max T remains near or beneath the 25th
percentile of the overall distribution, which seems pretty
unreasonable given the high heights. ECMWF EFI values would indicate
anomalous but not record temps, so will err on using guidance that
is warmer than the NBM  both days. Expect highs in the upper
80s to around 90, with overnight lows in the upper 50s to around
60.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
Key Message(s):

- Above normal temperatures to continue through the period
- Shower and storm chances return Tuesday afternoon and low chances
are expected through the end of the period

The ridge is expected to begin shifting eastward on Monday as the
deep trough continues to translate eastward. Despite this, above
normal heights are likely to continue. Given robust southwesterly
flow aloft & continued anomalous heights, as well as being ahead of
an approaching front, expect highs near the upper 80s again on
Monday afternoon. Guidance is in pretty good agreement that the
front should continue to slowly progress towards the region on
Tuesday and Wednesday. Flow aloft is forecast to relax across
the eastern CONUS, likely preventing the front from moving too
much over a few days. Expectation is that shower and
thunderstorm chances will increase on Tuesday and hang around
through at least Thursday. A moisture rich airmass south of the
remnant boundary, along with warm temps likely in the mid 80s,
should result in diurnal chances for scattered showers and
thunderstorms.

&&

.AVIATION /18Z FRIDAY THROUGH TUESDAY/...
VFR conditions expected through the TAF period.

Low level moisture return around surface high pressure over the
western Atlantic has supported the formation of a few diurnal
cumulus clouds this afternoon, but no ceilings are expected.
These clouds will quickly dissipate with the loss of diurnal
heating. As the moisture get trapped beneath an inversion there
is the potential for some stratus to form overnight. However
confidence in its formation/coverage is too low to introduce any
ceilings into the forecast at this time. If winds fully
decouple, there is also the potential for some patchy fog
formation at KAGS and KOGB, but again confidence in fog
formation is not sufficient to put any visibility restrictions
in the forecast. Winds will gust upwards of 15-18 mph at times
this afternoon, but then diminish overnight and remaining
southerly through the forecast period.

EXTENDED AVIATION OUTLOOK...Some patchy fog possible Sunday
morning as moisture continues to increase but confidence
continues to be fairly low.

&&

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

&&

$$