448
FXUS62 KCAE 291852
AFDCAE

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

.SYNOPSIS...
High pressure continues to linger just offshore and will help
drive warm southwesterly flow across our area today. 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/...
Upper ridge over the area shifts a little to the east today as a
trough approaches the Mississippi Valley. Surface high offshore
extending into the area will increase a bit of low level moisture
with southerly to southeasterly winds. That said, overall the air
mass remains relatively dry with precipitable water hovering around
1". Cumulus field has developed and is generally remaining
scattered, while warm advection has yielded temperatures in the
upper 70s and low 80s. Still some time for temperatures to peak, and
values should make it in the lower 80s for highs. With the upper
ridge shifting east, convection associated with the aforementioned
trough and surface front will be moving into the lower Mississippi
Valley this evening. This main area of precip should lift northwest
into the TN valley and weaken somewhat by tomorrow morning.
Expect an increase in mid and high level clouds overnight ahead
of the trough on southwest flow aloft. CAM models show
convection as far east as northwest Georgia by 30/12z Tuesday
morning. Overnight low temps a little warmer in the upper 50s to
around 60 with the increasing cloud cover.

&&

.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 /19Z MONDAY THROUGH SATURDAY/...
Mainly VFR conditions through the period.

FEW-SCT mainly mid-level clouds into this evening, maybe becoming
BKN but CIGs remaining VFR. Winds southwest to south 5 to 10 knots
becoming southeast early in the evening. High clouds increase late
in the evening and persist overnight. Guidance is suggesting a short
period of CIG restrictions possible near around daybreak Tuesday due
to stratus as low level moisture continues to increase. Otherwise,
winds continue out of the south around 10 kts. Scattered showers and
thunderstorms are then possible Tuesday afternoon, but that is
generally outside of this TAF period.

EXTENDED AVIATION OUTLOOK...Restrictions possible in scattered
thunderstorms Tuesday afternoon and evening.

&&

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

&&

$$