837
FXUS62 KCAE 120719
AFDCAE

Area Forecast Discussion
National Weather Service Columbia SC
319 AM EDT Mon May 12 2025

.SYNOPSIS...
Unsettled weather continues with shower and thunderstorm
chances through the early portions of the week. A few periods
could feature some stronger showers and thunderstorms as well as
very heavy rainfall, particularly today. Conditions begin to
dry out around midweek, with much warmer temperatures expected
by the end of the work week.

&&

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

- Continued showers and isolated thunderstorms with periods of
  heavy rainfall possible.
- Possible hydro issues in flood prone areas.
- Temperatures remaining cool.

Rinse and repeat kind of day. Upper level closed low continues
to spin west of the region, with shortwave energy rotating
around the base and then northward into the southeastern States.
Surface front south of the forecast area will have an area of
low pressure developing along it, helping to slowly push the
front northward as a warm front through the day. Deep moisture
moving northward from the Gulf, along with moisture moving
inland from the Atlantic, will all be over-running the surface
front. With pwat values between 1.6-1.8 inches, periods of heavy
rainfall will remain possible with each shortwave that tracks
across the area through tonight. WPC continues to show the
forecast area under a Slight Risk of Excessive Rainfall through
tonight, while SPC has much of the forecast area under a
Marginal Risk of severe weather. High confidence in heavy
rainfall threat, and can not rule out Flood advisories or even a
Flash Flood Warning somewhere across the area through tonight.
As for the Severe threat, much lower confidence in that
scenario for the majority of the county warning area. Best
chance for stronger storms should be along the northward moving
warm front in any areas that can get into the warm sector. Much
lower threat in areas that still remain in the surface wedge.
Another day of below normal daytime temperatures is expected
with forecast highs in the lower to mid 70s. Overnight temperatures
shouldn`t decrease much due to the clouds and rain with forecast
lows in the lower to mid 60s.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
Key Message(s):

- Isolated to scattered showers and thunderstorms Tuesday and
 Wednesday, with decreasing coverage and intensity.

- Local rivers may crest come Wednesday and into Thursday

- Temperatures closer to normal.

The upper low begins to transition into an open trough Tuesday
and Wednesday as it moves toward the northeast across the
eastern Tennessee Valley and Appalachia. The occluding surface
low also moves through here, lifting a warm front out of the FA
through the morning and afternoon, bringing more seasonable
temperatures in the upper 70s to low 80s. In general, with the
strongest upper forcing moving out of the region and with the
surface front lifting, rain/storm chances become more isolated
to scattered each day, and more likely toward the Pee Dee region
where it will be closer to lingering upper support.

Tuesday morning may see conditions more on the dry side as the
CWA finds its self in the dry slot before moisture then
increases again during the afternoon and evening with PWAT`s
around 1.3-1.4" as the base of the upper trough begins to pivot
in, driving the aforementioned showers/storms. Heavy rainfall is
not expected with the decreasing moisture and weaker forcing,
but any low end chance for periods of moderate to heavy rain
would be more confined toward the Pee Dee region. Severe storms
are not anticipated with this activity at this time despite
MLCAPE up to around 1000 J/kg mainly due to decreasing Bulk
Shear and upper forcing, but decent low level lapse rates and
mixing could aid in yielding an isolated storm on the stronger
side with forecast soundings showing moderate DCAPE values.

Wednesday is a rinse and repeat forecast similar to Tuesday as
the upper trough packs one more punch of PVA with PWAT`s
remaining around 1.3-1.4", bringing more isolated to scattered
rain showers and possible thunderstorms. Like Tuesday, an
isolated storm on the stronger side cannot be ruled out but the
main talking point come Wednesday is river forecast ensembles
and RFC river forecasts depict multiple rivers cresting at minor
to possibly moderate flood levels sometime Wednesday and
possibly Thursday from the multi-day rain event and thus
rainfall amounts especially through Monday will continue to be
monitored for any potential river flooding impacts that could
occur toward the midweek as river levels rise.

&&

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

- Warming trend to above average for the late week and into
  weekend.

- Staying mostly dry outside of any diurnal rain/storm chances
  with next chance of rain arriving for weekend.

The upper low finally departs into Thursday as upper ridging
takes over and NAFES mean PWAT`s drop to near average through
the period. With this ridging building in, temperatures begin to
reach above average and a taste of summer is given into the
weekend as warm and muggy conditions are expected. In terms of
rain chances, there could be outside diurnal shower/storm
chances Thursday and Friday as conditions become muggy but the
best chance of rain seems to hold off until the start of the
weekend when upper ridging becomes slightly more suppressed
with a deep trough digging into the upper Great Lakes, possibly
dragging a cold front and its associated rain/storm chances into
the FA for the weekend.

&&

.AVIATION /06Z MONDAY THROUGH FRIDAY/...
Expect recent conditions to persist through Monday night.

With the primary cut off low remaining west of the forecast area
through the period, not expecting much change in the forecast
pattern through tonight. Deep moisture continues to move inland
from both the Gulf and the western Atlantic. Majority of the
guidance shows ceilings remaining ifr through the period, while
visibilities alternate between vfr and mvfr in showers. So from
a categorical perspective, all sites will remain in IFR through
tonight. Winds are expected to be E/ESE from 5-10 kts through
the 24 hour TAF period.

EXTENDED AVIATION OUTLOOK...Periods of rain and thunderstorms
will continue early this week as moisture feeds into the region.
The threat of restrictions lowers mid-week when drier air will
move into the region.

&&

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

&&

$$