Severe Thunderstorm Warning 70, NWS Columbia, SC

Area Forecast Discussion
National Weather Service Columbia SC
307 AM EDT Tue May 5 2020

.SYNOPSIS...
Front stalled from the Upstate southeast to the coast, just
south, but paralleling I-26 will begin to gradually nudge
northward overnight. This boundary will lift to the NC/SC line
on Tuesday with severe threat again Tuesday evening. A cold
front push through Tuesday night. A much cooler and drier
airmass expect behind this system late week.

&&

.NEAR TERM /THROUGH TONIGHT/...
A boundary is currently draped over the forecast area with
scattered storms developing mainly to the north producing some
hail. While discrete storm activity has diminished in the
northern forecast area, a MCS continues to move through the SC
Upstate enhanced by shortwave energy and upper level divergence.
While some HiRes models do indicate a weakening trend, the line
of storms is bowing as it moves due east. While this system
remains strong enough to continue to propagate on its own, there
is some ML CAPE exceeding 1000 J/KG in central SC. Do expect
this line to continue its eastern movement with the main threat
damaging wind gusts, although hail and downpours will be
possible, mainly across the northern Midlands.

After this system moves through, the front is expected to lift
north of the area which should lead to another unseasonably warm
day with highs in the 80s and low 90s with breezy southwest
winds allowing for additional warm air advection through the
day. With the front stalling once again another chance for
storms to develop along it, although again the best upper level
forcing looks to be in the northern forecast area as shortwave
energy moves along the NC/SC border. HiRes ensemble mean keeps
significant instability in the northern FA, which makes sense
with temps well above average and moisture more than sufficient.
Shear will remain significant with forecast soundings for
Lancaster also indicating steep mid level lapse rates. As a
result, strong winds, large hail will be possible and even
isolated tornadoes cannot be completed ruled out. This is very
dependent on where exactly the front sets up but will have to
keep a close eye on areas in the northern Midlands. Cold front
will push through tonight with winds remaining elevated, keeping
temperatures in the upper 50s and 60s overnight, although this
front will usher in a much drier and cooler airmass behind it.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
Models remain fairly consistent that the cold front will push
through the forecast area by Wednesday morning, keeping the area
dry through the day. The models show a deep trough developing
across the eastern portion of the country Wednesday night into
Thursday. It will be breezy overnight as the pressure gradient
will still be fairly tight between the strengthening area of low
pressure along the New England coast and high pressure building
in from the Plains. On Thursday, high pressure will continue
settle southward to the Gulf coast and Southeast by Thursday
night. The weather looks dry through the period with
temperatures below normal for the period. Expect highs in the
upper 60s to lower 70s with overnight lows in the 40s

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
Deep trough remains across the eastern CONUS into the weekend,
with temperatures below normal through the period. Friday night
into Saturday will see the next chance for rainfall as the next
system moves through the region. Moisture will once again be
somewhat limited ahead of the front which will also limit
instability along the front. Will carry chance pops Friday
night with the frontal passage.

Cooler and drier weather is again expected Saturday and Sunday
behind the exiting cold front as high pressure settles in over
the region. High temperatures will generally be in the 70s with
lows in the 40s to lower 50s.

&&

.AVIATION /07Z TUESDAY THROUGH SATURDAY/...
VFR Conditions expected to continue over the next 24 hours.

A boundary is currently draped over the forecast area but looks
to be north of the terminals, nearest to CAE/CUB. Some storms
have developed to the north where there has also been an upper
level shortwave pushing through. A second batch of storms will
push into the SC Upstate later tonight but continues to exhibit
a easterly motion, which should keep the bulk of storm activity
north of the terminals through the night. Kept VCSH in CAE/CUB
but think convective activity should remain further north. Some
stratus may develop around sunrise this morning, especially in
areas that receive significantly rainfall overnight but at this
point, kept the cloud deck scattered at all the terminals,
keeping VFR conditions. With the boundary lifting further north
today, expect WSW winds with gusts as high as 15 to 20 knots. A
cold front will move through the area tonight which may lead to
some lower CIGs but VFR conditions still expected to continue.

EXTENDED AVIATION OUTLOOK...A cold front will move into the
area Friday into Friday night with possible restrictions in
showers and thunderstorms.

&&

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

&&

Special Weather Statement
National Weather Service Columbia SC
1229 AM EDT Tue May 5 2020

SCZ016-022-116-050500-
Chesterfield SC-Southern Lancaster SC-Kershaw SC-
1229 AM EDT Tue May 5 2020

...Strong Thunderstorms Will Impact Portions of northwestern
Chesterfield...Southern Lancaster and northern Kershaw Counties Until
100 AM EDT....

At 1228 AM EDT...National Weather Service doppler radar indicated a
strong thunderstorm near Buford, or 13 miles east of Lancaster,
moving east at 35 mph.

  HAZARD...gusty winds 35 to 45 mph and pea sized hail.

  IMPACT...expect minor damage to tree limbs and blowing around of
           light, unsecured objects. Minor hail damage to plants,
           trees and crops is possible. Damage to windshields is
           unlikely.

Some locations in the path of this storm include...
Pageland, Carolina Sandhills Wildlife Refuge, Buford, Jefferson,
Ruby, Mount Croghan, Chesterfield Ruby Middle School, High Point Fire
Station, Tradesville, Bay Springs Fire Station, Forty Acre Rock
Preserve, Taxahaw and Central High School.

LAT...LON 3481 8012 3455 8014 3464 8066 3482 8062
TIME...MOT...LOC 0428Z 273DEG 30KT 3471 8055

HC

Special Weather Statement
National Weather Service Columbia SC
117 AM EDT Tue May 5 2020

SCZ016-050545-
Chesterfield SC-
117 AM EDT Tue May 5 2020

...Strong Thunderstorms Will Impact Portions of east central
Chesterfield County Until 145 AM EDT....

At 117 AM EDT...National Weather Service doppler radar indicated a
strong thunderstorm 9 miles east of Carolina Sandhills Wildlife
Refuge, or 12 miles southwest of Cheraw, moving east at 35 mph.

  HAZARD...gusty winds 40 to 50 mph and up to penny sized hail.

  IMPACT...expect minor damage to tree limbs and blowing around of
           light, unsecured objects. Minor hail damage to plants,
           trees and crops is possible. Damage to windshields is
           unlikely.

Some locations in the path of this storm include...
Cheraw, Cheraw State Park, Society Hill, Patrick and Cheraw Fish
Hatchery.

LAT...LON 3460 7981 3453 7983 3453 7984 3451 7986
      3449 7990 3450 7991 3449 7993 3453 8015
      3469 8014 3470 7987 3467 7985 3465 7980
      3464 7980 3461 7978
TIME...MOT...LOC 0517Z 271DEG 32KT 3459 8007

HC