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323
FXUS62 KGSP 021806
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
206 PM EDT Sun Jun 2 2024

.SYNOPSIS...
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A typical summer pattern is returning during the first half of the
week with daily afternoon thunderstorm chances.  Showers and
thunderstorms will likely increase in coverage for Wednesday and
Thursday as a weak cold front approaches our area.  Drier weather is
expected to return by the end of the week.
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&&

.NEAR TERM /THROUGH TONIGHT/...
As of 10:05 AM Sunday...shower coverage has diminished over our CWA
during the past few hrs. A more well-defined line of heavier showers
with a few embedded thunderstorms further south is about to move into
our western-most NC zones. It`s doubtful that we will see much (if any)
thunder/lightning over the next few hrs, as no significant instability
is expected to materialize over our area until this afternoon.

Otherwise, upper ridging continues to shift east today as a baggy s/w
trof crosses the FA. Little forcing will be had with this feature as
it supports a weak sfc bndry pushing east during max heating. Soundings
show lowering saturation of the column today and limited available
sbCAPE or even muCAPE for that matter. A couple of the more unstable
models indicate arnd 800 j/kg of afternoon CAPE, while other guidance
is holding arnd 300 J/kg less. Little shear will be had as well, with
profiles consistent with less than 15 kts 0-6km shear. Also, with the
weak upper trof, mid-level LRs remain unremarkable. So, still expect
isolated to sct thunderstorms developing ahead of a loose sfc conver-
gence zone aft 17z continuing thru 00z, yet the prospect of severe
criteria being met is low. Highs today will will be held about 5 to
7 degrees below normal due to deep moisture. Mins drop to near normal
levels with a chance of dense fog before daybreak. The exact location
of fog formation is unclear currently and will roughly depend where
the heavier rain falls this afternoon. But for now the NC mtn valleys
have the best chance for dense fog.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
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As of 130 pm Sunday: A weak short wave ridge will meander across the
region through much of the period, before shunting to the Coast by
Wed evening, as an area of large scale height falls overspreads the
Appalachians and vicinity. SW low level flow will provide the heat
and humidity for diurnal deep convection Tue afternoon...although
coverage is expected to be somewhat limited due to weak anticyclonic
flow aloft and relatively low precipitable water values. Moderate
instability should nevertheless allow for isolated to widely
scattered coverage (20-40 PoPs) across much of the area, esp the
high terrain.

A cold front associated with aforementioned height falls will enter
the picture from the west by the end of Wednesday, enhancing diurnal
convective chances during the afternoon/evening, especially over the
mountains, where 60-70 PoPs are warranted. A consensus of short term
guidance suggests destabilization could be quite robust Wed
afternoon, with sbCAPE of 2000+ J/kg likely. Shear parameters are
forecast to be quite meager, but 0-3km shear of 15-20 kts could
support some local cell clustering along outflow boundaries which
would pose a threat of isolated downbursts, while a few pulse severe
storms also appear to be a good bet. With the front expected to
steadily cross the region Wed night, some degree of convective
coverage will likely persist long after the end of the diurnal
heating cycle, albeit with a warning risk of strong-to-severe
convection. Temps are expected to be a category or so above climo
through the period.
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&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
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As of 150 pm Sunday: A trough associated with a deep upper low is
expected to develop across the East early in the extended...
gradually shifting off the East Coast through the period. An
associated frontal boundary is expected to be draped over or near
the forecast area at the start of the period, with scattered
convection (generally 30-50 PoPs) expected from late morning through
the afternoon Thursday. Lower theta-E air is expected to begin
filtering in from the west by the end of the day, bringing an end to
substantial convective chances from Friday through next weekend,
although a few showers (PoPs 30% at most) will be possible across
the mountains within deep NW/upslope flow regime Friday through
Sunday. Other than a stretch of near-to-slightly below normal
temperatures expected Fri night through Sat night, temps are
expected to remain a category or so above normal through the
period.
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&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
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At KCLT and elsewhere: Sct showers with some embedded thunderstorms
are expected to linger over the fcst area thru the afternoon and into
the evening. Have TEMPOs for thunder at all taf sites until roughly
24z with some lingering vcsh after that. After the rain moves east
of our area later tonight/overnight, expect cigs and visby to lower.
I think there`s a decent chance that all of our taf sites (except for
KCLT) will see a few hrs of IFR cigs and at least MVFR visby overnight
and into the morning. KAVL has the best chance of seeing LIFR or lower
around sunrise. Expect visby to improve and the lower cigs to sct out
by roughly 14z late tomorrow morning with VFR for the rest of the day.
We will likely see another round of diurnal isolated to sct convection
Monday afternoon/evening, which I have mentioned in a PROB30 for KCLT
beginning at 20z. Otherwise, winds will go light to calm later tonight/
overnight and continue to favor a S to SW direction on Monday.

Outlook: Diurnal shower and thunderstorm chances with associated
restrictions will linger thru the middle of next week.
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&&

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

&&

$$

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