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355
FXUS62 KCAE 251050
AFDCAE

Area Forecast Discussion
National Weather Service Columbia SC
650 AM EDT Sat May 25 2024

.SYNOPSIS...
A frontal boundary is expected to stall near the forecast area
resulting in chances for showers and thunderstorms through the
weekend. Another, more organized system is expected to cross
the eastern US Monday and Tuesday with additional chances for
thunderstorms. Drier weather is expected to return Wednesday.

&&

.NEAR TERM /THROUGH TONIGHT/...
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A shortwave trough crossing the area early this morning will be
responsible for isolated convection across the northern and
central Midlands. Meanwhile skies are clearing a bit behind
this feature, which could lead to some light patchy fog across
parts of the CSRA.

The shortwave trough will shift off the Mid-Atlantic/Southeast
US coast later today, setting up a west-northwest flow aloft
across the area. Despite this typically drier flow aloft,
precipitable water values will remain up in the 1.5-1.6 inch
range through the day.

Most of the CAMs do not appear to be doing very well
initializing this morning, and are very inconsistent with their
depiction of the formation and evolution of convection this
afternoon. The southern Midlands and CSRA do appear to remain
rain-free into at least early afternoon however. Another
stronger shortwave will approach from the west late this
afternoon and evening, triggering isolated to scattered showers
and thunderstorms, with the greatest coverage across the central
and eastern Midlands.

Moderate to strong instability will be in place today, with
SBCAPE values ranging from 1500-2000 J/kg. In addition, HREF
forecast soundings show a well pronounced inverted-V sounding,
indicative of a damaging wind threat with any thunderstorms
that manage to become severe. The SPC Day 1 Outlook also
highlights a Marginal Risk for severe thunderstorms today across
the area.

Temperatures will remain unseasonably warm, with highs in the
upper 80s to lower 90s.

Tonight, the convection should dissipate by late evening once
the short wave shifts east of the area and some weak subsidence
develops in its wake. CAMs do show a remnant MCS dissipating
before reaching the area, but if it holds together longer than
the models currently show some showers could occur overnight,
although not forecast to do so at this time. Generally, some
clearing should occur later tonight with lows in the upper 60s.
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&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
Upper ridge is progged to extend through the Plains on Sunday with a
mid-level shortwave moving through the Ohio Valley. Upper level flow
across our area will be zonal with increasing southerly flow near
the surface. PW values will hover between 1.5" and 1.7" with
dewpoints in the mid and upper 60s. Temperatures rising to low 90s
be afternoon should yield plenty of surface instability, anywhere
from 1500-2000 J/kg. Isolated to scattered showers and thunderstorms
are expected to result, however there is some question as to how
widespread they will be given the flat ridging and only some weak
shortwaves pushing through the flow. That said, the better chances
for convection remains generally northeast of the I-26 corridor.
Storms will have the potential to produce some gusty damaging winds
and heavy downpours, given DCAPE > 750 J/kg. Mild Sunday night given
lows in the low 70s with slight precip chances relegated to the
northern CWA.

Severe weather threat appears slightly better on Monday with
convection focused ahead of and along a frontal boundary. The
aforementioned upper trough will slide into the Ohio Valley and take
on a neutral or slightly negative tilt. PW values are expected to
remain above 1.6", with LI values of -4 to -9 extending from the
coast to the Upstate. SB CAPE values again increase upwards of 2000
J/kg with DCAPE >1000 J/kg, particularly across the CSRA. Shortwave
energy combined with the approaching front will serve as a better
focus for convection, and so think the severe threat may be a bit
higher. Temperatures still make the low 90s for highs with upper 60s
for lows Monday night.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
Trough generally remains to our north through the middle of the week
with zonal flow aloft. The passing front will usher in drier air
with dewpoints returning to the 50s. Temperatures cool a bit more by
Thursday, with highs in the low 80s. PW values return to around or
slightly below 1" (given GEFS ensemble mean; ECENS is closer to
0.75") which will make it difficult for precip to develop. Felt it
prudent to remain with NBM guidance at this time due to differences
in the model guidance (deterministic solutions and their ensembles).
As such, no rain in the official forecast Wednesday through Friday.
Overnight temperatures also get a reprieve with lows in the mid 60s
to upper 50 by the end of next week.

&&

.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
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Reduced visibilities have developed at AGS due to patchy fog
early this morning, resulting in MVFR conditions with at least
temporary IFR conditions expected through about 13Z. Scattered
showers and thunderstorms possible after about 20Z as a weak
upper level trough moves through the area combined with a
moderately unstable air mass. Some temporary flight restrictions
will be possible as a result at any of the terminals in the
20-02Z time frame.

EXTENDED AVIATION OUTLOOK...Restrictions possible at times
through early next week in afternoon and evening showers and
thunderstorms.
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&&

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

&&

$$