094
FXUS62 KCAE 300549
AFDCAE

Area Forecast Discussion
National Weather Service Columbia SC
149 AM EDT Tue Apr 30 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 /UNTIL 8 AM THIS MORNING/...
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 /8 AM THIS MORNING THROUGH 6 AM WEDNESDAY/...
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 /06Z TUESDAY THROUGH SATURDAY/...
VFR conditions expected through the early afternoon.
Restrictions possible late this afternoon into the evening as
convection moves through the area.

High pressure offshore is extending into the area. The ridge
will weaken this afternoon as an upper trough approaches the
area. Satellite indicating mid and high level clouds will
increase across the area through the morning. Some mixing in the
boundary layer and less nocturnal cooling expected so fog not
expected early this morning. The air mass will become weakly to
moderately unstable by this afternoon. Scattered to broken
cumulus possible late morning through the afternoon but should
remain VFR. Ceilings more likely to be mid level. Convective
models show scattered convection developing ahead of the upper
trough late this afternoon into the evening. Brief restrictions
possible mainly 20z-01z time period. Patchy light showers
possible through 06z Wednesday.

EXTENDED AVIATION OUTLOOK...Restrictions possible Tuesday night.
Additional restrictions become possible again by Saturday ahead
of a frontal boundary.

&&

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

&&

$$