Mc Cormick, South Carolina Weather Forecast Discussion

723
FXUS62 KCAE 212338
AFDCAE
Area Forecast Discussion
National Weather Service Columbia SC
738 PM EDT Sun Sep 21 2025
.SYNOPSIS...
High pressure and dry conditions start off the work week. Rain
chances will then be on the increase from mid-week onward.
&&
.NEAR TERM /UNTIL 7 AM MONDAY MORNING/...
Key message(s):
- Tranquil weather continues into the overnight.
Satellite this evening shows a few lingering cumulus moving in
from the northeast and passing high-level clouds arriving from
the southwest. Skies should remain mostly clear tonight allowing
temperatures to fall into the lower to mid 60s by daybreak.
Winds should become light and variable, favoring an easterly
direction. While areas of patchy fog cannot be ruled out towards
daybreak, favoring areas near bodies of water, a 20kt low level
jet (LLJ) should support stratus over fog in most locations.
&&
.SHORT TERM /7 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
Key message(s):
- Warm and mainly dry to start off the work week.
Another beautiful stretch of weather is expected to start off
the work week as we careen towards the end of astronomical
summer. Weak upper level trough axis will continue to work its
way northeastward during this period, gradually losing
amplification and being replaced by increasing heights by
Tuesday night. This weakening shortwave will allow the surface
ridging that is present across the area today to lose its punch
and shift eastward into the Atlantic. The result will be a
gradual shift in our low-level flow with southeasterly flow
gradually becoming southwesterly by early Wednesday. Despite a
modest, slow increase in PWs during this period, the upper level
pattern will remain unfavorable for widespread precipitation.
The only real chance may be Tuesday evening as the sea breeze
works its way into the coastal plain, aided by surface onshore
winds. Highs will bump up from the upper 80s on Monday into the
low 90s on Tuesday as heights begin to slowly rise over the
area. Lows should remain in the mid 60s.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
Key message(s):
- Rain chances return for mid to late week.
- Above normal temperatures through Thursday, then turning
  cooler.
Deep troughing is forecast to develop across the central US,
shifting into the eastern CONUS gradually as the period
progresses. Deep southwesterly flow is shown by global models
and their ensembles, with PWs continuing to rise ahead of the
approaching trough and surface front. PWs by Thursday and Friday
are forecast to rise up into the 140%-160% of normal range
(~1.8"-2.0") which will foster showers and thunderstorms both
THursday and Friday as the front slowly moves through the
region. Ahead of this, temps are forecast to be quite warm, with
highs possibly in the mid 90s on Wednesday as heights rise into
the 588dm range. Thursday could see temps approach this level,
but potential clouds and rain showers cloud whether or not temps
will get that warm on Thursday. Friday through Sunday looks to
feature more normal temps, though there is significant
uncertainty in this period. Guidance is very mixed on what
happens with the deep, amplified trough as it pushes into the
southeastern US. We have had a tendency towards cut off lows
recently, so my hunch is to think that may happen with this
trough. However, the spread amongst teleconnections forecasts
makes larger scale forecasting in this timeframe difficult as
well, so it is hard to say that forecaster confidence beyond
Friday`s forecast is any higher than low at this point. It does
look like next weekend should favor temps nearer to normal but
really lacking confidence to say much more than that at this
time.
&&
.AVIATION /23Z SUNDAY THROUGH FRIDAY/...
Restrictions possible again tonight.
Afternoon diurnal cumulus has dissipated with only some patchy
cirrus overhead. Light northeasterly winds becoming near calm
overnight although there is a 20 knot low level jet forecast
tonight which may keep the boundary layer mixed a bit. As
surface ridge shifts further offshore of the New England coast
low level flow is expected to become more easterly off the
Atlantic which may support increased chances of stratus late
tonight, especially across the eastern part of the area. Highest
confidence in restrictions at OGB but earlier HRRR runs show
stratus expanding into the central Midlands potentially. Decided
to go with a prevailing MVFR cig at OGB from 10z-14 with tempo
to lower IFR cig and included a tempo group from 10z to 13z or
14z other terminals to account for possible stratus. Winds
should pick up by 15z from the east around 5 to 7 knots and any
stratus should dissipate by late morning.
EXTENDED AVIATION OUTLOOK...Periods of early morning
fog/stratus remain possible, especially at AGS and OGB through
early next week. Moisture increases mid-week leading to
increasing chances for rain and widespread restrictions.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...None.
GA...None.
&&
$$

NWS CAE Office Area Forecast Discussion