Severe Thunderstorm Warning 25, NWS Columbia, SC

Area Forecast Discussion...UPDATED
National Weather Service Columbia SC
214 PM EDT Mon Mar 31 2025

.SYNOPSIS...
A line of thunderstorms will move across the Southeast today
with severe storms possible this afternoon. Well above normal
temperatures expected for late week with possible record highs
late week and next weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
Key Message(s):

- Severe Thunderstorm Watch in effect for the CSRA and portions
  of central SC. Damaging winds are the primary threat but a few
  storms may produce a tornado and large hail.

Update: Skies clearing over the CSRA and Midlands. This will
allow the air mass to destabilize ahead of a line of
thunderstorms which will move into the forecast area this
afternoon. The largest threat still appears to be areas of
damaging winds along the line of thunderstorms. That said,
conditions remain sufficient to have a few stronger storms
embedded within the line which potentially produce a tornado or
large hail.

Previous Discussion: An upper level trough continues to shift
eastward across the middle of the country which will push a cold
front through the area by tonight. Ahead of the front today,
continued southerly low level flow around the western Atlantic
surface high will provide continued warm and moist advection
over the forecast area leading to air mass destabilization
through the day. Morning stratus may delay or impact the initial
destabilization but guidance suggests MLCAPE values will exceed
1000 J/kg during peak heating with modest but sufficient
effective wind shear around 30-40 knots which should support the
threat of severe weather.

Latest HRRR runs consistently showing this initial convective
line diminishing as it moves east of the mountains but leaving a
residual outflow boundary somewhere across the northern
Midlands. This could become a focus for enhanced helicity and a
increased tornado threat when afternoon convection moves into
the region.

Hi-res guidance is in reasonable agreement developing
convection across the Gulf Coast states after 12z which then
tracks eastward through the day encountering an increasingly
unstable high theta-e environment resulting in a line of strong
convection moving through our area mid to late afternoon
(18z-01z) with possible isolated discrete cells developing ahead
of the line. Hi-res guidance also showing some updraft helicity
tracks moving across the Midlands and CSRA with a more recent
enhancement of them across the northern Midlands (likely
associated with the forecast outflow boundary) which is a change
from previous forecast thinking that the tornado threat would
primarily be confined to the CSRA and southeast Midlands. So
while there does not appear to be a significant tornado threat,
with a more likely storm mode being cold pool dominated linear
multicellular segments, the tornado threat does exist across the
entire forecast area. As mentioned, damaging wind gusts are the
primary threat of severe weather given the fairly
unidirectional wind profile but large hail cannot be ruled out
either. PWAT values continue to be high (over 200% of normal)
and will support heavy rain potential but storm motion should be
high enough to limit flash flood threat.

Temperatures today should warm again well into the 70s with
some lower 80s possible in the eastern Midlands, depending on
how quickly the lower stratus can burn off. After the convection
pushes east of the forecast area this evening lingering cloud
cover will limit radiational cooling and expect some return of
stratus due to abundant low level moisture in place until the
cold front pushes through. Cold advection should commence behind
the front late tonight and overnight lows expected to fall into
the 50s ranging from the lower 50s west to upper 50s east.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
Key Message(s):

- Cooler and dry Tuesday with the beginning of a warming trend.

Tuesday will be the coolest day this week and likely the driest as
PWATs drop to around 0.5" behind the departing cold front. Highs
will generally be in the 70s for most places with dewpoints falling
back into the 40's or perhaps upper 50s across the southern forecast
area. Broad offshore high pressure and upper ridging develops into
Wednesday, with some moisture returning to the area and daytime
temperatures increasing another 5-8 degrees. A few upslope and
isentropically forced showers are possible Wednesday, but accums
should be fairly light given PWAT values between 1" and 1.25".
Overnight lows should be in the 50s Tuesday night and 60s Wednesday
night.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
Key Message(s):

- Highly anomalous warmth expected with near record high
temperatures possible Thursday through Sunday.

The big story in the extended continues to be the potential for near
record or record high temperatures. The surface high becomes well
established offshore with upper level ridging continuing to build
over the area through the upcoming weekend. NBM high temperatures
are in the upper 80s to low 90s Thursday through at least Saturday,
though the spread by Sunday is a little larger and temperatures may
cool off a few degrees. The EC EFI continues to show highs in the
80th-90th+ percentile across the entire area with a few Shift of
Tails bullseyes of 1 Thursday through Saturday, and values drop off a
bit to generally 80th percentile for Sunday, so there is good model
support for these expected temperatures. The uncertainty of
temperatures Sunday and Monday is likely due to timing differences
for the next front late next weekend, which will also probably bring
the next best chance for a good bit of rainfall.

&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
Isolated showers and possible storms now entering near AGS/DNL
and moving toward the east with MVFR ceilings still seen at all
sites except at AGS/DNL where it has been bouncing between VFR
and MVFR.

MVFR ceilings remain with scattered to broken clouds between
1,800 and 2,500 ft or so with near 10 kt southwest winds
continuing. The main line of strong to severe thunderstorms is
fast approaching eastern GA with isolated showers moving into
AGS/DNL at this time, continuing east. Some of these will
maintain the possibility of developing into thunderstorms as
instability increases ahead of the main line. This activity
should be entering near CUB/CAE by 19z or so and some of this
may reach near OGB a little later. The timing for the main line
of storms is on track with it currently looking to enter AGS/DNL
by 19-20z, CUB/CAE by 20-21z, and OGB by 20-22z. This has a
history of bringing strong winds with some gusts over 35 kts and
ceiling and visibility restrictions. These conditions may last
for a couple hours as the main line passes. Behind the line,
some isolated showers may linger into the evening but the main
impact behind this line of storms continues to be another
stratus deck that looks to build back in after 6-8z with light
and variable winds, but some guidance has not been as aggressive
with how low the deck gets before being pushed out by the front
and thus currently have MVFR ceilings and visibilities through
around daybreak.

EXTENDED AVIATION OUTLOOK... Early morning low clouds continue
to be possible Wednesday and Thursday morning with abundant
moisture but no precipitation is expected.

&&

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

&&

Preliminary Local Storm Report
National Weather Service Columbia SC
431 PM EDT Mon Mar 31 2025

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0328 PM     Tstm Wnd Dmg     3 NE Plum Branch        33.88N 82.22W
03/31/2025                   McCormick          SC   911 Call Center

            Trees down on Harmony Rd, New Hope Rd, and
            Whitetown Rd in Plum Branch. Time estimated
            based on radar.

&&

JAQ

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