188
FXUS62 KGSP 200144
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
944 PM EDT Thu Sep 19 2024

.SYNOPSIS...
The limited coverage of any showers and storms on Friday afternoon
will be confined to the mountains.  Meanwhile, high pressure begins
to build into the region from the north and west giving our region a
dry weekend. Temperatures will be above normal through the weekend
then closer to normal through the middle of next week.

&&

.NEAR TERM /THROUGH FRIDAY/...
As of 930 PM: Up to 500 J/kg of SBCAPE still present out there per
SPC Mesoanalysis, albeit now with some nocturnally originated CIN;
showers and t-storms have kept going albeit becoming increasingly
isolated. Weak northerly steering flow continues to bring cells
south into the Greenville area and into our northern tier of NC
counties, the latter seemingly driven by a weak vort max encircling
the East Coast low. The storm motion and moderate rainfall rates
suggest minimal hydro threat. New PoPs reflect the propagation
of the current storms although values diminish over the next 2-3
hrs as CIN becomes dominant. Overnight temps still look to drop
into the u50s across the mtns and crossover temps will likely be
reached or exceeded; most areas should see at least light fog,
with locally dense fog in the mtn valleys and through the Catawba
basin, if not elsewhere in the lower Piedmont.

A drier day is on tap for Fri with less cloud cover as deep
subsidence increases from the west and high pressure dominates
at the sfc. There may be some limited convective activity across
the mtns due to ridge top convergence, but coverage of precip
will be low-end due to the aforementioned subs and midlevel
warming. Highs Fri will likely reach a couple cats above normal
across the forecast area.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
As of 145 PM EDT Thursday: Upper ridge will be dominating the
Southern Plains as we move into the short term, with trough in place
over the East Coast. With heights rising through the period,
increasing subsidence will generally keep pops out of the forecast,
but a weak shortwave moving down the northerly flow aloft may bring
just a bit of moisture to the area briefly Saturday night, so cannot
rule out some showery activity in the NW NC Piedmont. Bigger story
will be the temperatures increasing through the period, with
temperatures trending upwards both Saturday and Sunday,
uncomfortably unseasonably warm with highs approaching mid 90s in
the Upper Savannah by Sunday afternoon as the upper ridge axis
pushes closer to us and the upper trough begins to lift out.
Elevated dewpoints underneath the increased ridging aloft will keep
overnight lows a couple of degrees above normal as well.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
As of 200 PM EDT Thursday: The upper ridge will continue to push
east as we move into the extended, eventually flattening and
shifting slightly south as a mid-level low works its way out of the
Rockies and across the Northern Plains. A stronger system passing
across southern Canada will drag a cold front across the Great Lakes
on Sunday, approaching the OH Valley late in the weekend and
eventually toward the Southern Appalachians as we begin the new work
week, bringing a return of pops to the mountains. Timing this far
out is uncertain, and the first round of precip may dry up before
the secondary round associate with the Northern Plains wave moves in
Tue-Wed. High temperatures will be knocked back down closer to
seasonal normals with the increasing clouds and precipitation,
though increasing moisture will keep overnight lows above normal.

&&

.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
At KCLT and elsewhere: Added a TEMPO for KGSP/KGMU given cells
moving south off the Escarpment this evening. Otherwise
remaining cu will dissipate leaving just FEW- SCT mid cloud for
most of the night, with winds remaining light. Although mixing
was better today dewpoints remained at summerlike mid 60s to
near 70; coupled with a slight easterly flow above the sfc,
radiation fog/stratus appear likely in the mtn valleys and also
near rivers in the Piedmont. Hence a period of IFR is included
at KCLT/KAVL/KHKY in the morning; with lesser support from
guidance and drier soils have gone no worse than MVFR at
KGSP/KGMU, although trends will need to be monitored overnight.
Winds pick up from the N to NE during the morning but should
remain less than 6 kt. At KCLT slow improvement is expected with
VFR not returning until midday. Isolated SHRA/TSRA possible in
the mountains but chance too low to mention at KAVL. Winds could
veer to near due E if not ESE late in the day but with speeds
light and impact low, did not introduce another group to reflect
shift.

Outlook: No appreciable return of moisture or precip chances
expected until early to middle of next week. Daybreak restrictions
could recur each morning especially in mountain valleys.

&&

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

&&

$$

SYNOPSIS...DEO
NEAR TERM...SBK/Wimberley
SHORT TERM...TDP
LONG TERM...TDP
AVIATION...Wimberley