905
FXUS62 KCAE 070533
AFDCAE

Area Forecast Discussion
National Weather Service Columbia SC
Issued by National Weather Service Greenville-Spartanburg SC
133 AM EDT Wed May 7 2025

.SYNOPSIS...
Near normal temperatures and dry conditions expected today.
Increasing rain chances begin Wednesday and continue each day
into the upcoming weekend.

&&

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

- Rain chances increase today
- Cooler temps than the past few days are expected with copious
  cloud cover in place

An unsettled weather pattern over the next week is forecast to begin
today. Shortwave ridging, currently just to the west of our area, is
forecast to continue shifting eastward tonight. Southwesterly flow
should overspread the area and moisture will begin advecting into
the region. This should manifest itself in cloud cover by dawn, with
mid and high level clouds expected to be over the region. A big
batch of robust convection across the deep south is expected to push
towards the area tonight, weakening as it does so. Showers are
expected to maintain into the region, arriving just after dawn and
into the mid-morning hours. THese should generally be light in
nature, with total rainfall under 0.2" at most. Expect these to be
out of the area or dissipated by mid-late afternoon. Clouds and rain
showers should keep temps cooler today, likely down in the low to
mid 70s. Tonight, a quick moving branch of the upper level jet
streak is likely to place the region within the favorable right
entrance region as it lifts northward over the central Appalachians.
Combine that with a robust 500 hPa shortwave passing through and
scattered showers are expected to develop again after a break. These
are most likely to get going after 3am, with hi-res guidance coming
into good agreement on this idea. So lows will likely be elevated in
the low 60s given cloud cover and approaching rainfall.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
Key Message(s):

- Scattered to numerous showers and thunderstorms expected both
  Thursday night and Friday
- Limited severe threat anticipated, with heavy rainfall and
  lightning the primary threats
- Near to above normal temps expected both days

Showers are forecast to continue into Thursday morning as a robust
shortwave passes through the forecast area. Generally, guidance
suggests that most of this activity will weaken by midday, with
sunshine likely coming out during the afternoon hours. We may not
have much in the way of showers or storms Thursday afternoon as
subsidence behind the shortwave keeps things pretty quiet until the
prefrontal surface trough approaches on Thursday night. Highs are
expected to be quite warm in the low to mid 80s Thursday afternoon.
As we get into Thursday night and Friday, more widespread
coverage is expected to develop as a series of fronts approach
amidst strong synoptic scale forcing. All of this is in
association with our primary weather maker through this weekend
- a developing closed low. The evolution of the sharp trough
that gets pinched off over the Ozarks on Thursday night and
Friday is important to both this period & the long term period.
Broad, zonal flow aloft is forecast to overspread a moisture
rich and relatively unstable environment Thursday night and
especially Friday. A strong shortwave over the northeastern US
is forecast to force a broad surface low pressure system, with a
cold front pushing southeastward along this. The favorable
shortwave activity aloft & moisture profile ahead of the front
will combine to yield numerous showers and thunderstorms both
Thursday night and again on Friday. And storms could be numerous
on Friday afternoon and evening as the front pushes into the
area. GEFS probabilities of >500 j/kg of SBCAPE on Friday
afternoon is in the 60-80% range, backing up what the
operational model is showing. Highs will likely be in the 80s
again on Friday afternoon, though uncertainty exists with how
early convection gets going which could impact highs.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
Key Message(s):

- Daily rain chances likely to continue Saturday through the
  early next week.
- Heavy rainfall looking increasingly likely, with 2"+ possible
  over the course of a few days.
- Below to (potentially) well below normal daytime temperatures
  likely.

A very favorable setup for rainfall is expected Saturday through at
least Monday, with substantial (2"+) rainfall becoming
increasingly likely over the course of several days. Ensemble
and operational guidance continues to be in good agreement on
the synoptic scale pattern, with a cut off low gradually
settling into southern MS Valley by Saturday morning. Meanwhile,
rapid height rises are expected across the northern Rockies and
Great Plains, with a sharp shortwave racing northeastward away
from the CONUS off the coast of New England. These features are
expected to foster a favorable setup for this cut off low to
slowly meander eastward, with the Carolinas in a favorable setup
for multiple rounds of heavy rainfall Saturday through at least
Monday, possibly on Tuesday. This should begin on Saturday as a
rare early May cold air damming event looks to setup behind
Friday`s front. With strong convergence aloft over the Mid-
Atlantic, a strong surface high should develop and keep surface
northeasterly flow locked into place across our forecast area
both Saturday and Sunday.

Meanwhile, robust moisture transport & warm
advection is expected aloft, with PWs around 150% of normal in
place. The result should be widespread rainfall on Saturday and
again on Sunday. The heaviest rain is beginning to look like it
should fall in the Sun night through Mon night timeframe. A strong
upper level jet streak looks to develop in this timeframe, placing
the area within a favorable location for strong upper level
divergence. This is forecast to foster increasingly strong moisture
transport across the area and may yield multiple bands of heavy
rainfall by Monday night. GEFS probability of 24 hr QPF >1" has
increased to 40-50% across most of our area in this timeframe, which
adds confidence to the synoptic setup. By this point, the upper
level low is forecast to begin slowly shifting north or
northeastward, with another day of scattered to numerous
showers/storms expected on Tuesday of next week. GEFS total precip
in this timeframe has increased, with probability of >2" in the 70-
100% range, with probability of >4" total QPF in the 30-50%
range across the central forecast area. Both probabilities have
increased since this time yesterday. This rainfall is really
needed as we have been quite dry to start the year, but all of
this falling over the course of couple of days may not be as
beneficial as I previously thought. We`ll have to keep a close
eye on it as this kind of setup does tend to yield some isolated
flash flooding issues. Highs throughout the period will likely
be below normal, potentially well below normal on Sat/Sun. Lows
are expected to be near or above normal given widespread cloud
cover and robust low-level moisture.

&&

.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
VFR conditions expected through mid morning then possible
restrictions Wednesday afternoon.

Satellite imagery showing dense cirrus approaching the region from
the west associated with some convection pushing eastward through
the MS Valley. Expect VFR cigs to prevail into mid morning but as
precipitation moves into the region by early afternoon there is
potential for MVFR cigs and this is handled by a PROB30 group.
Chances for MVFR restrictions seem better by Wednesday evening after
precipitation ends but low level moisture remains in place. Winds
generally light through the period from the west late morning
through the afternoon.

EXTENDED AVIATION OUTLOOK...

Thursday-Saturday: Multiple rounds of showers and thunderstorms are
possible through the period as an upper level low approaches from
the west, especially toward the late week. Periods of MVFR/IFR
conditions are possible at all terminals.

&&

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

&&

$$

SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...
AVIATION...