369
FXUS62 KGSP 241743
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
143 PM EDT Fri May 24 2024

.SYNOPSIS...
Temperatures will remain several degrees above normal each day
through the holiday weekend. Daily chances for showers and
thunderstorms. A cold front on Monday brings cooler and drier
conditions for the middle of next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 1248 PM EDT Friday: No major changes this afternoon.  Cu field
visible on satellite, and upstream convection has now moved out over
north-central AL.  12z CAMs are now available, and there`s better
consensus on timing and evolution, with arrival of activity sometime
after 5pm, continuing into the late evening as it moves east.

Otherwise...new development of showers and storms will probably be
tied to the approach and passage of remnant MCVs and outflows from
storms out west. These may come in a few waves in the otherwise
quasi-zonal flow, but when they pass through, will help to trigger
or bring an uptick in coverage of storms. With that, also perhaps
an increase in potential for severe storms. The environment will
remain somewhat favorable with sufficient buoyancy on the order
of 1500-2500 J/kg of sfc-based CAPE depending on the model,
and enough deep layer shear through the early evening on the
order of 20-30 kt, which could make storms more interesting. No
issues with the Marginal Risk on the Day 1 outlook and it seems
reasonable to expect a few warnings to be issued mainly in the
afternoon/evening. Similar to this past evening, expect some
of this activity to persist into the early morning hours as the
buoyancy is slowly used up. Won`t rule out locally heavy rain,
either. High/low temps will be about five degrees above normal.

&&

.SHORT TERM /SATURDAY THROUGH MONDAY NIGHT/...
As of 215 AM Friday: Picking up Saturday with gradual strengthening
of an area of high pressure over the Gulf and a weak ridge extending
northward over the CWA. As the ridge progresses eastward, shortwaves
traverse the Carolinas and up the chances for additional showers and
thunderstorms. Guidance keeps a steady stream of moisture in the
area through the forecast period and beyond, with instability
remaining prevalent. Latest guidance does bring some questions as
far as coverage on Saturday, especially outside the mountains. EURO
is trending for a few more areas outside the mountains, but the GFS
trends drier. Cannot rule out a few thunderstorms at this time.
Sunday looks to dry out a bit as the upper ridge axis crosses over
the CWA and suppresses rain chances. However, height rises does make
Sunday the warmest day with low 90s popping up in most places east
of the mtns. Meanwhile, an upper low forms over the southern plains
and lifts NE, bringing a chance for a FROPA across the mountains
Monday, increasing rain and TS chances once again. At this time,
guidance has decent upper flow of 30-40kts and sufficient
instability. Modeled soundings show steep sfc-3km lapse rates, but
with a strong T/Td spread and inverted-V. Will continue to monitor,
though it appears to be more typical TS with a frontal passage.
Overall, hotter temps returning for most of the holiday weekend and
TS chances each day.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
As of 220 AM Friday: Continuing with Monday night onward, the
pattern becomes generally more dry as far as the synoptic pattern
goes. Any remaining FROPA should be weakened closer to Monday night
and pinch off rain and thunderstorms chances by Tuesday. As the
strong upper low lifts towards the Great Lakes, a strong ridge
builds over the central CONUS, taking on an omega pattern toward the
north. Meanwhile, high pressure amplifies zonally to the south and
balances height rise/falls through at least Wednesday. Long range
models show an upper trough dipping southward from the Great Lakes.
Given how far out the model runs are, there is still much
uncertainty as to how far south and if the trough reaches the CWA.
GFS suggests a stronger pressure gradient and possible rain chances,
while the EURO remains less enthusiastic and keeps the area dry.
After Wednesday, the ridge axis from the central CONUS propagates
eastward toward the CWA and shunts rain chances with strong
subsidence aloft. Temperatures should remain close to climo through
the period as well.

&&

.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
At KCLT and elsewhere: Somewhat more clarity on the convective
forecast for today, with hi-res guidance now indicating that
convection will arrive in the Savannah River Valley and cross
into the Upstate around 5pm.  In light of this, TEMPOs for the
Upstate sites will begin 20-21z.  As the system pushes east,
guidance depicts it deteriorating.  This actually introduces a
little new uncertainty as to whether convection will actually
make it to KCLT...but have chosen to retain mention of TS, in a
shortened TEMPO group, for the evening.  Thereafter, some lingering
sprinkles may persist in the wake of the main wave.  Sites which
receive ample rainfall this evening are likely to see patchy MVFR
fog again overnight, as residual debris cloudiness thins out and
skies clear.  That will scatter out quickly in the morning, giving
way to another convectively-active day.  Timing is uncertain,
but guidance is in decent agreement on another wave of SHRA/TS
making its way across the area during the afternoon.

Outlook: A unsettled pattern will linger thru the rest of the
weekend and into early next week, allowing for diurnal shower
and thunderstorm chances each day and fog development each
night/morning.

&&

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

&&

$$

SYNOPSIS...CP
NEAR TERM...MPR/PM
SHORT TERM...CP
LONG TERM...CP
AVIATION...MPR