106
FXUS62 KCAE 300008
AFDCAE

Area Forecast Discussion
National Weather Service Columbia SC
808 PM EDT Mon Apr 29 2024

.SYNOPSIS...
On Tuesday there will be a chance of thunderstorms in the afternoon
with a low threat of severe weather. Broad ridging aloft will
develop for the rest of the week limiting the extent of convection
and allowing temps to rise above normal, then precip chances
increase over the weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
Cumulus clouds over the area are dissipating as the sun sets
this evening leading to mostly clear skies to begin tonight. As
the upper ridge shifts to the east and moisture increases with
southwesterly winds aloft. A line of showers and storms remains
well to the west of the area as of 8pm, entering western
Alabama. This line will continue to advance through the Deep
South into tonight with forcing provided by an upper shortwave.
All indications from HiRes guidance is our area remains dry
through tonight with increasing clouds over the area downstream
of these showers and storms to the west. Low temperatures remain
a bit warmer tonight with the increasing clouds with lows in the
upper 50s.

&&

.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
The axis of an upper level ridge will shift further offshore on
Tuesday. As the ridge shifts east, an upper trough will move
across the Deep South. Convection associated with the trough is
expected to weaken through the early morning hours Tuesday.
Virtually no SREF members bring the convection into the forecast
area before dissipating so we have kept PoPs out of the
forecast. However it would not be the first time that overnight
convection has held together despite no model guidance showing
it.

Either way the upper level trough will cross the forecast area
on Tuesday. Divergence aloft, moisture advection through SW low
level flow, and convergence along the previous day`s outflow
boundary should promote convective development in the after noon
hours. Low and mid-level lapse rates are supportive of
thunderstorms but are not very steep. The interquartile range of
sbCAPE values from the SPC HREF range between 400 to 1000 J/kg.
Deep layer (0-6km Shear) values are around 20 kts with weak
850mb wind fields. This may limit the threat of organized
convection.

Thunderstorms should develop in the afternoon either scattered
or focused along a possible remnant outflow boundary. There`s a
low threat of severe weather given the modest lapse rates and
wind fields. A slot of mid-level dry air in the afternoon
suggests the biggest threat would be isolated downburst winds or
small hail. As the trough shifts east in the evening expect the
bulk of the thunderstorm activity to move out of the forecast
area with some lingering convection possible into the night.

Highs will be in the low to mid 80s Tuesday with lows in the
upper 50s to around 60 degrees.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
Drier air will move into the area for Wednesday as an upper
level trough moves east of the area. PWAT values will still be
around 1 inch and there may still be a few showers along the
coastal regions where low level moisture is higher. But overall,
convection should be suppressed by the dry air and warmer temps
aloft.

Global ensemble means favor ridging aloft over the Southeast
through much of the long term. This along with generally
southerly flow favors temperatures above normal with highs on
Thursday and Friday in the mid to upper 80s with some locations
possibly breaking 90 degrees. Over the weekend and into early
next week, the overall pattern supports flattening the ridge.
This could lead to a series of shortwaves moving over the
forecast area. This in combination with PWAT values from 1.5 to
1.75 inches supports a chance of showers and thunderstorms each
day through the remainder of the long term.

&&

.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
Forecasting mainly VFR conditions through the period.

Scattered clouds across the forecast area have almost diminished
with the approach of sunset. Exception in across the western CSRA
where satellite still indicates scattered mid clouds due to
slightly better moisture. Expecting mostly clear conditions with
only a few clouds in the low to mid levels for much of the
night. In upper levels, some cirrus should stream eastward and
across the region through the night. Better moisture moves in
after sunrise Tuesday ahead of the next approaching rainmaker
from the west. Skies will become more broken, with ceilings
lowing into the mid to lower levels through the late morning and
into the afternoon. Heights still forecast to remain vfr at this
time, and most guidance seems to agree with that. Showers should
remain west of the taf location through much of the taf period,
with isolated to scattered showers possible developing and
approaching all locations towards the end of the period. Have
placed mention of vcsh late in all tafs. Light southerly winds
overnight around 5 knots, then increasing up to 10 knots through
the day Tuesday.

EXTENDED AVIATION OUTLOOK...Restrictions possible in scattered
thunderstorms Tuesday evening. Additional restrictions become
possible again by Saturday ahead of another system.

&&

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

&&

$$