709
FXUS62 KGSP 200547
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
147 AM EDT Thu Jun 20 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 TODAY/...
As of 1:35 AM Thursday: An elongated stripe of thick cirrus
continues to linger over our western zones, with more sct
cirrus extending well east of the main stripe. These clouds
will likely slow radiational cooling somewhat over the next
few hrs, but they should sct out as the overnight/morning
wears on. They could also limit the amount of patchy fog
that develops over the mtn valleys. We shall see.

Otherwise, the 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 airmass.
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 /TONIGHT 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 /06Z THURSDAY THROUGH MONDAY/...
At KCLT and elsewhere: Expect VFR conditions to continue thru the
06z taf period across our area. Some patchy mtn valley fog may form
again overnight and into the morning, but it`s not expected to affect
KAVL, however it cannot be entirely ruled out. Otherwise, I expect
little change in the synoptic pattern for Thursday with dry high
pressure in control. The shield of bkn cirrus currently over our
area will gradually sct thru the morning with another round of sct
VFR clouds expected this afternoon and evening. Winds will remain
light to calm at most sites thru the morning and then pick up from
the ENE outside of the mtns for the aftn/evening. At KAVL, winds
will pick up from the SE this aftn/evening.

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

&&

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

&&

$$

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