000
FXUS62 KCAE 091756
AFDCAE

Area Forecast Discussion
National Weather Service Columbia SC
156 PM EDT Tue Apr 9 2024

.SYNOPSIS...
There is a slight chance of showers mainly north and west of the I-
20 corridor today. The next chance for impactful rain waits until
Wednesday night into Thursday as a strong trough approaches. Strong
to severe thunderstorms are possible with this system. Gusty winds
are likely on Thursday and Friday as a strong low pressure system
pushes to our north. Drier, warmer weather fills in behind the front
for the upcoming weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
Broad southwest flow aloft in place over the area as the upper ridge
axis shifts toward the Atlantic coast.  Mid-level shortwave
continues to move through the Upstate into central NC with
widespread showers occurring mainly north and northwest of the CAE
CWA. Main effects here have been dense overcast skies which have
limited our daytime heating, as temperatures have really struggled
to rise and are generally still in the mid to upper 60s across the
Midlands and CSRA. Dewpoints have come up slowly through the day,
with values now in the mid to upper 50s.

The surface ridge remains offshore and will slowly drift east which
should increase our low level southerly flow at H85. The
incoming moisture is expected to raise precipitable water
levels to around 1.3"-1.4" by this evening. Any residual showers
should lift north away from the area overnight as the primary
disturbance pushes northeast. With southerly flow continuing,
expect cloud cover will hang around tonight keeping temperatures
warm. Low temperatures overnight on the mild side with this in
mind, generally around 60 degrees.

&&

.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
Key messages in the short term:

1) There is a low chance (5-15%) for severe weather on Thursday.

2) Confidence is high for strong non-thunderstorm winds Thursday
into Friday.

Wednesday is expected to remain dry through the day ahead of an
incoming system. The incoming system is forecast to be centered over
the Southern Plains Wednesday morning where a closed mid-level low
and strong surface low pressure are anticipated to be located. These
features are expected to translate eastward into the Lower
Mississippi Valley by Wednesday night. As a result, some warm air
advection over our area on Wednesday should aid in bringing warmer
than average temperatures in the afternoon.

Key message 1:

The mid-level closed low is expected to open up and become
negatively tilted as it treks into the Great Lakes region. This
forces the surface low to translate northeast and strengthen as it
does. A trailing cold front is expected to move toward the area as
well. Convection associated with this frontal boundary and pre-
frontal boundary is expected to be ongoing in the Gulf states and
spreading east and north. As a result, an initial round of showers
and thunderstorms are forecast to move into the area Thursday
morning. There is some slight timing differences in the exact timing
of when this activity moves across the region. Synoptically, there
is plenty of support for strong to severe thunderstorms if
thunderstorms can form. Southeast winds at the surface combined with
strong south to southwesterly winds at 700 mb and above will lead to
bulk shear values of around 50 knots or more. Latest guidance
potential of 0-3 km helicity values approaching 500 m2/s2 during the
morning hours. These values are expected to remain elevated through
the day. There are a couple of limiting factors to the severe threat
on Thursday, especially in the morning. The upstream activity in the
Gulf states will likely limit the amount of instability available
during the morning hours as most of the available instability
probably will be gobbled up by that activity. The cold front is
forecast to move through the area in the late afternoon to early
evening time frame. Again, the limiting factor appears to be the
amount of instability available for thunderstorms to develop. The
morning activity could work over the atmosphere, leaving the area
too stable in the afternoon. However, if there are breaks in cloud
cover during the say, we could see just enough instability to spark
a few thunderstorms. Overall, the chances remain on the lower side
(5-15%).

Key message 2:

Confidence remains high that we will see strong winds outside of any
thunderstorm activity. As the system strengthens, the pressure
gradient is expected to tighten causing strong winds. Winds just
above the boundary layer are forecast to be around 40 knots through
much of the day. As the atmosphere mixes through the day, some of
this stronger wind will likely make it to the surface. Ensembles are
indicating this as well. For example, the NBM is showing nearly 100%
probability of wind gusts greater than 30 mph for pretty much the
entire forecast area, and a 50% probability of 40 mph gusts for
portions of the area. If this trends continue a Lake Wind Advisory,
and potentially a Wind Advisory, will be needed. The gusty winds
continue into Friday, but the gusts are forecast to be a bit lower
in the 30-35 mph range.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
The long term period looks to be mainly quiet and warm as upper
ridging and surface high pressure builds over the area through the
middle portions of next week. As a result, temperatures are looking
to be well above average by midweek.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
Mainly VFR conditions to continue through the TAF period.

BKN-OVC skies but CIGs remain VFR. An upper level disturbance will
move through the area with a few showers mainly north and west of
the terminals, ending late tonight. SFC wind SLY/SWLY 5 to 10 knots
becoming southeast after 10/00z. There is a slight chance of some
brief MVFR VSBYs at the AGS/DNL/AIK terminals early Wednesday
morning, but confidence is not low so covered this with a TEMPO.
Winds increase Wednesday morning out of the south around 10 kts with
continued OVC skies.

EXTENDED AVIATION OUTLOOK...Potential and confidence for
restrictions increases Wednesday night through Thursday as a cold
front approaches and moves through the region. Increasing winds
Wednesday night with very strong and gusty winds expected Thursday
through Friday. VFR returns for the upcoming weekend.

&&

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

&&

$$