428
FXUS62 KGSP 290729
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
329 AM EDT Mon Apr 29 2024

.SYNOPSIS...
The warming trend will continue through mid week as high pressure
remains centered just off the Atlantic Coast. A weak cold front is
expected to move through the area on Tuesday bringing scattered
showers and thunderstorms. Another front is expected to approach
the Carolinas by late week and bring more showers and thunderstorms
to the area.

&&

.NEAR TERM /THROUGH TONIGHT/...
An off-shore sfc high continues to ridge across the area making for
dry conds outside of an area of low clouds across the srn BR
escarpment. These clouds will linger and become a little more
widespread thru the morning as upslope flow continues. Not a great
fog threat this morning as the sfc-layer decouples yet remains
weakly mixed and relatively dry. However, cold air drainage will
likely instigate fog development, possibly dense, across the Little
TN Valley within the sw/rn NC mtns.

An east coast upper level ridge finally becomes unblocked and begins
to shift east thru the period. This will shunt a sfc high further
east into the Atl making for decent warm air advection in the llvls
in advance of an active cold front expected on Tues. The atmos will
remain quite dry today as soundings show dry LCLs and a well defined
subs inversion lowering across the wrn zones. So, don`t expect much
afternoon cloudiness unlike the past few days and temps will respond
with highs in the l80s non/mtns and u70s mtn valleys. A pre/frontal
environment sets up overnight as the llvls moisten and mid/upper
clouds also increase in coverage thru daybreak. A few mech lift
enhanced showers will likely develop across the far sw/rn NC mtns
before daybreak and have maintained mid-chance PoPs with isol
thunder before dawn. Mins will remain a cat or so abv normal tonight
due to WAA sfc mixing and increasing column moisture.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
As of 3:05 AM EDT Monday: The short-term fcst picks up at 12z on
Tuesday with an embedded upper shortwave approaching our area from
the west. The shortwave will gradually translate over our area late
Tuesday into early Wednesday and help push the upper ridge axis off
the Atlantic Coast. The shortwave will then move off the Carolina
Coast late Wednesday with heights rebounding in its wake and upper
ridging amplifying again as the period ends early Thursday. At the
sfc, broad high pressure will be centered off the SE Coast with warm,
SLY low-level flow over our area as the period begins. At the same
time, a weak cold front will approach our CWA from the west and move
thru our area Tuesday aftn/evening. This timing should result in a
decent amount of sfc-based instability across much of our area (for
late April) when the boundary moves thru. Thus, sct to numerous showers
and thunderstorms are expected for Tuesday aftn/evening. This insta-
bility coupled with the above-mentioned upper shortwave may produce
some stronger thunderstorms over our area, but 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. Temperatures start out about a category above climatology
on Tuesday and continue to warm thru the period.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
As of 2:55 AM EDT Monday: The extended forecast picks up at 12z on
Thursday with upper ridging in place over the Southeast CONUS. Over
the next couple of days, numerous weak upper shortwaves will lift to
our north and towards the Ohio Valley region. At the same time, broad
upper trofing will morph into a complex upper low just west of the
Great Lakes by the end of the week on Friday. As we head into the
weekend, the active northern stream will suppress the upper ridge
across the Southeast as additional embedded upper shortwaves trans-
late NE and over our area. At the sfc, reinforcing high pressure will
migrate southward from New England on Thursday and eventually settle
just off the mid-Atlantic Coast on Friday. At the same time, a more
robust low is progged to eject out of the Plains and lift towards the
Great Lakes. This system will bring another cold front to our area as
the weekend begins. Most of the long-range guidance still has the front
moving thru our area on Sat with sct to numerous showers and thunder-
storms likely Fri aftn thru much of Sat. Weak high pressure slides in
behind the front on Sunday, although the operational models diverge
considerably wrt the synoptic pattern beyond this point. Temperatures
will start out well-above climatology on Thurs and moderate some over
the weekend, yet still remain above climo.

&&

.AVIATION /08Z MONDAY THROUGH FRIDAY/...
At KCLT and elsewhere: Surface ridging will dominate the pattern
thru the TAF period and help make for VFR conds all sites. Low cloud
development will be confined across the srn NC mtns, as LCLs remain
quite dry. No big VSBY issue either thru the morning hours. Winds
round the sfc ridge and align generally sw/ly to s/ly with low-end
gust possible mainly at KAVL and KHKY this afternoon.

Outlook: A frontal system could bring a round showers and storms to
the area on Tuesday, with more of a potential for isolated diurnal
convection on Wednesday and Thursday. The next front could bring
better coverage of showers and storms on Friday.

&&

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

&&

$$

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