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647
FXUS62 KGSP 051728
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
128 PM EDT Wed Jun 5 2024

.SYNOPSIS...
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Scattered showers and thunderstorms will develop again on Thursday.
Dry Canadian air will mix across the area Friday and persist into
the weekend. A chance of thunderstorms returns to the region Sunday
and continues into the first half of next week.
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&&

.NEAR TERM /THROUGH TONIGHT/...
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As of 1228 PM EDT Wednesday: Some substantial changes were made to
PoPs based on the latest hi-res guidance.  It`s unclear exactly how
quickly (or extensively) convection will be able to develop this
afternoon given the lack of destabilization permitted by ongoing
widespread cloud cover.  Will need to re-evaluate this with the
upcoming 3PM forecast package.

Several shortwave perturbations are forecast to lift across
the southeast states and into the Southern Appalachians
today. The approach of the lead shortwave trough in concert with
another remnant MCV emanating out of an upstream MCS across
Mississippi/Alabama will provide more than enough forcing to
instigate numerous to widespread showers and thunderstorms
through the afternoon into the evening hours...but as noted
earlier destabilization could become an issue (see the 14z HRRR,
for example, which is completely disinterested in giving us
thunder today).

Otherwise...The 00z suite of CAM guidance has been consistent
in depicting a lead batch of showers lifting across the southwest
mountains this morning with coverage increasing across the mountains
early this afternoon. Activity will spread out of north Georgia,
along with lead development, with multicell clusters/loosely
organized line segments across the Upstate and into the North
Carolina foothills and Piedmont. Late erosion of the morning
clouds may hamper the magnitude of insolation and resulting
destabilization, but modest surface-based CAPE of 1500-2000
J/kg should be relatively easy to come by within a very moist
airmass. Lapse rates will remain poor and nearly moist adiabatic
with weak downdraft CAPE and tall/skinny CAPE profiles. While
this will not be the most favorable environment for microbursts,
increasing 850mb flow late this afternoon into the evening
associated with a weak low-level jet translating across the region,
may prove sufficient for loose convective organization. As such,
a few instances of locally damaging winds will be possible with
any clusters/line segments that can organize along a composite
cold pool and/or outflow boundary collision. Of note, though, is
that the increasing low-level flow with the low-level jet, while
weak, results in non-zero hodograph curvature. 0-1km shear and SRH
approaches 20kts and 100 m2/s2, respectively, in several near-storm
forecast soundings along the I-85 corridor. While probabilities
are rather low, a brief tornado cannot be completely discounted,
especially should there be a favorable outflow boundary interaction
that can locally enhance SRH and ingestion of horizontal streamwise
vorticity.

At least scattered showers and a few thunderstorms will likely
linger into the evening hours with a handful of showers festering
overnight. There are indications that a line of thunderstorms over
Tennessee just ahead of a cold frontal boundary will make a run at
the mountains around or shortly before daybreak. Guidance differs
with how these storms may evolve, thus have kept rain chances in
the likely rain and not quite categorical just yet. Otherwise,
another mild night can be expected with upper 60s to low 70s
dewpoints greatly limiting any cooling.
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&&

.SHORT TERM /THURSDAY THROUGH SUNDAY/...
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As of 100 PM Wednesday...An amplified system over the Great Lakes
states will push a cold front through the area by Thursday evening.
This will lead to drier and thus more comfortable conditions for
Friday and Saturday. With surface high pressure in place, lows
Friday night will drop into the 55-60 range in the Piedmont and to
the upper 40s to lower 50s in the mountains. Highs both Friday and
Saturday will be near climo, but with low relative humidity.
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&&

.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
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As of 110 PM Wednesday...The mid level system over the Great Lakes
will further amplify creating a little more active northwest flow
pattern on Sunday and Monday. This will lead to the return of pops
for these days and nights, but there is a lot of uncertainty as to
where and when any storms might occur. Drier conditions will return
for the middle of next week as the system pushes through the area.
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&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
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At KCLT and elsewhere: A challenging TAF forecast for the 18z
issuance.  Widespread MVFR to even isolated IFR ceilings remain
in place circa 1715z, which is somewhat inhibiting the instability
needed for more a more robust convective environment.  That said,
the majority of recent hi-res model runs suggest that we`ll scatter
out in the next hour or so, permitting destabilization followed by a
round of afternoon convection as a supporting upper feature passes
overhead.  So, we still expect TSRA at all the terminals later
this afternoon.  Timing has been tweaked for TEMPOs.  Showers may
linger into the late evening before drying up overnight; another
round of MVFR to IFR low ceilings is expected toward morning,
and visibilities may be reduced at any locations receiving ample
rainfall today.  Tomorrow, restrictions are depicted lifting much
more quickly than they have today, and the consensus is for another
round of thunder in the mid afternoon, associated with an advancing
frontal circulation.

Outlook: Drier air will move into the area Thursday night into
Friday morning with improving restrictions into the weekend.
High pressure will linger through Saturday before another system
approaches on Sunday or Monday.
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&&

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

&&

$$

SYNOPSIS...DEO
NEAR TERM...MPR/TW
SHORT TERM...SCW
LONG TERM...SCW
AVIATION...MPR