506
FXUS62 KGSP 301103
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
703 AM EDT Tue Apr 30 2024

.SYNOPSIS...
A cold front will push through the forecast area today bringing
scattered showers and thunderstorms. Dry and warm high pressure
builds across the region Wednesday through Thursday, before another
active frontal system moves in Friday and lingers through the
weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 6:35 AM EDT Tuesday: A thicker deck of mid-level clouds con-
tinues to spread further east over our area. A broad area of sct
to numerous showers, with some embedded thunderstorms, continues
to gradually make its way eastward and is now moving into our
western-most zones.

Otherwise, an embedded upper shortwave will approach the western
Carolinas this morning and gradually move over our fcst area later
today and into early Wednesday, helping to push upper ridging off
the Atlantic Coast as the near-term period is ending. At the sfc,
broad high pressure will remain centered off the Southeast Coast
with light, SLY low-level flow over our area this morning. At the
same time, a weak cold front will approach our CWA from the west
and move thru our area this afternoon/evening. This timing will
result in a decent amount of sfc-based instability, on the order
of 500 to 1000 J/kg, across much of our area by mid-afternoon.
Thus, numerous showers and sct thunderstorms are expected this
afternoon/evening. The instability coupled with the upper short-
wave may produce a few stronger storms over our area, but with
generally unimpressive lapse rates it`s doubtful that any storms
will become severe. Regardless, the boundary should be moving east
of our CWA by early Wednesday with weak high pressure sliding in
behind it as the period ends. As such, PoPs taper off to just a
slight chance over the I-77 Corridor by the end of the period,
early Wednesday. Temperatures today will moderate by a few deg
outside the mtns, with highs near 80 this afternoon. They will
be notably cooler over the higher terrain, with highs struggling
to reach 70 in the mtn valleys.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
As of 105 AM Tuesday...A mid-level trof axis continues to shift east
of the area to begin the short range period. This will give way to a
building upper ridge across the east coast, which will control the
weather across the FA thru Thu night. Profiles remain quite dry with
PWATS remaining below 1.0 inches each day, so along with neg
forcing, rain chances are nil with mainly fair-wx Cu each day. Winds
will be weakly cold advective as sfc high pressure builds in from
the north, yet high temps will reach the low to mid 80s each day in
a modifying airmass. With the n/ly to ne/ly flow, sfc dewps and RH
values wont increase much, so expect rather nice feeling weather for
late April.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
As of 150 AM Tuesday...The ext range forecast remains unsettled as
upper ridging finally breaks down in advance of mlvl srn stream
energy. The latest op models generally agree on a modest h5 s/w
approaching the FA Fri pushing an active sfc bndry in from the west,
while sfc ridging breaks down across the nrn GOM supplying very good
moisture flux to the system. This wont be a very dynamic system as
deep layered shear remains less than 30 kts with only a 60 kt upper
jet core arriving by Sun evening. Thermo profiles indicate a
saturated column likely with skinny CAPE on the order of 700-1000
J/kg. So, expect some strong thunderstorms each day with high
rainfall rates possible. An organized severe threat looks low-end as
aforementioned dyno remains low and mlvl LRs area held less than
optimal while a highly moist sfc bndry settles across the area thru
Sun, possibly into Mon. Low level winds remain s/ly to se/ly each
day and temps will remain abv normal, with a drop off to near normal
levels Sat due to a better chance of widespread cloudiness and
precip.

&&

.AVIATION /11Z TUESDAY THROUGH SATURDAY/...
At KCLT and elsewhere: Expect VFR conditions to persist thru day-
break as the western edge of a sfc high lingers over our area. A
cold front will approach from the west this morning and move thru
the western Carolinas this afternoon and evening. Rain chances
increase across the western terminals (KAVL and the SC Upstate
terminals) by late morning with VCSH beginning just before noon.
Being further east, KHKY and KCLT should remain dry a bit longer
with any showers reaching them a few hrs later. Sct thunderstorms
will be possible during the afternoon and evening across the fcst
area. Thus, I have PROB30s for TSRA at all terminals beginning in
the afternoon and going into the evening with lingering VCSH. Winds
will remain light to calm overnight and into the morning. They will
pick back up by late morning and continue to favor a S to SW direc-
tion thru the period. Low-end gusts are possible this afternoon,
especially at KCLT and KHKY, where I included them in the taf.
Otherwise, cigs should generally remain VFR outside of any TSRA.

Outlook: Scattered showers and thunderstorms will remain possible
thru late tonight. More numerous showers and storms are expected
on Saturday ahead of a cold front.

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...None.
SC...None.

&&

$$

SYNOPSIS...SBK
NEAR TERM...JPT
SHORT TERM...SBK
LONG TERM...SBK
AVIATION...JPT