398
FXUS62 KGSP 200215
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1015 PM EDT Wed Jun 19 2024

.SYNOPSIS...
High pressure atop the region will suppress any storms from
developing this week until moisture returns on Saturday. A heat wave
gets underway on Friday and remains hot through the start of next
week. A weak cold front approaches from the north early next week
but is expected to stall out then dissipate.

&&

.NEAR TERM /THROUGH THURSDAY/...
As of 1000 PM: A stripe of a stthicker cirrus can be seen on the
nighttime RGB product over the Southern Appalachians. These clouds
may be slowly the radiational cooling somewhat, but overall,
skies should be mostly clear with varying amounts of cirrus
overnight. With previous update, did add a little more fog mention,
given the forecast lows in the mountain valleys are a few degrees
below the current sfc dewpts. The rest of the forecast looks
on track.

Otherwise...Upper anticyclone and attendant ridge will remain
west-through-north of the forecast area, with deep easterly flow
expected through much of the period. The low level flow is expected
to weaken tomorrow, as surface high sags south and weakens across
the western Atlantic...and a weak easterly wave approaches the
Southeast Coast. This should result in a slight warm-up of 1-2
degrees on Thursday afternoon. Min temps will otherwise again
fall to near-normal levels thanks to the relatively dry air
mass. Said air mass will continue to limit diurnal instability to
meager-at-most levels, with little-to-no chance of afternoon/evening
convection through the period.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
As of 142 PM EDT Wednesday: The week should end with typical
summer heat that starts to build into the weekend. A breakdown of
sorts in the large eastern upper anticyclone should be complete by
Friday, with one center migrating to the TN Valley region and other
offshore, separated by a weakness brought on by a weak easterly
wave that runs into the Southeast Coast. Although this might
suggest some increase in precip potential, especially Saturday,
the model guidance keeps that potential near the coast, in part
because of how strong the cap remains in place across our region
through Saturday, even over the higher terrain. The upshot is
that we stay relatively dry as sfc high pressure lingers over the
region. That makes the high temps the main concern, although merely
normal on Friday, but then creeping up a few degrees above normal
into the middle 90s in places east of the mtns. Be that as it may,
the humidity will not be high enough to raise the heat index more
than a deg or two above the air temp, so no big problems yet.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
As of 222 PM EDT Wednesday: The second half of the weekend looks
like a quick transition aloft as the old upper anticyclone to
our west breaks down further and the center retrogrades to the
Southwest on Sunday, while in its place a cyclonic flow aloft is
introduced by a northern stream system moving across the Great
Lakes to eastern Canada/New England through Monday. At a minimum,
the pattern shift favors a return to at least climo precip probs
starting on Monday, but the mid-upper troffiness lingers into
the middle of the week, suggesting less of a diurnal dependence
to the convection and more potential for a shower/storm at any
time of the day. The expectation is for the region to finally get
into a more pulse-severe type regime. A thermal ridge will remain,
allowing temps to climb about five degrees above normal each day,
while an increase in the humidity will finally allow the heat index
to climb upwards toward more uncomfortable values, but perhaps not
yet into Heat Advisory range. Because this should be our first
real hot weather of the season, it still warrants a mention in
the HWO east of the mountains.

&&

.AVIATION /02Z THURSDAY THROUGH MONDAY/...
At KCLT and elsewhere: VFR conditions are expected thru the period,
but some mountain valley fog may form overnight (not expected to
affect KAVL, but cannot be entirely ruled out). Little change in the
pattern for Thursday, with dry high pressure in control. Light ENE
to ESE wind expected at the Piedmont sites, and SE at KAVL. Periods
of thick cirrus, with another fair wx cu field forming late morning
thru the aftn with VFR-level bases.

Outlook: An expansive upper ridge will keep things mostly dry
with VFR conditions thru Friday. Mountain valley fog and/or low
stratus will be possible each morning. Isolated diurnal convection
in the mountains possible Saturday, then a return to more scattered
convection across the region Sunday and Monday.

&&

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

&&

$$

SYNOPSIS...DEO
NEAR TERM...ARK/JDL
SHORT TERM...PM
LONG TERM...PM
AVIATION...ARK