983
FXUS62 KGSP 031837
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
237 PM EDT Thu Apr 3 2025

.SYNOPSIS...
Warm temperatures continue this afternoon with spotty light showers
expected, mainly over the Upstate.  Mostly quiet, but very warm,
conditions will last through the end of the week and into
Saturday. A strong cold front brings rain and possibly
thunderstorms on Sunday and Monday, before dry and chilly
conditions return Tuesday and beyond.

&&

.NEAR TERM /THROUGH FRIDAY/...
As of 235 PM EDT Thursday: Any lingering wedge has completely
eroded as the area is now entrenched under south-southwesterly
WAA. A deck of stratocu will continue to roam overhead through
peak heating. Dewpoints remain elevated in the mid to upper 60s,
while lingering insentropic lift and differential heating has
allowed for scattered showers to spark across portions of the area,
with an obvious focus at the south-southwest upslope regions along
the Escarpment. Can`t rule out a few thunderstorms as SBCAPE of
1500-2500 J/kg and 40-50 kts of deep layer shear will help aid in
possible organized convection. There is a lack of true forcing,
which will inhibit further initiation, especially with warm air
aloft being captured by a deepening anticyclone offshore the
Southeast Coast. Any lingering precipitation should wane off after
sunset, with a few lingering showers across the upslope regions
possible through the early overnight hours.

Guidance have been persistent with a nocturnal low stratus
deck developing south and east of the Escarpment by daybreak
Friday. Expect this deck to slowly scatter out through during
the mid- to late-morning hours Friday. This could limit max
temperatures if the clouds hold on longer than anticipated. Daily
max temperature records will be in jeopardy at AVL/CLT/GSP on
Friday as even anomalously high thicknesses (~590 dm) continue to
build into the region from the aforementioned anticyclone, with
highs in the mid to upper 80s across most locations outside of
the higher elevations. Some of the CAMs try to develop a few peak
diurnal showers Friday afternoon, but warm air aloft will help cap
overall coverage and the best locations for an afternoon shower
or thunderstorm will be in the upslope regions of the southwest
NC mountains.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
As of 139 PM EDT Thursday: A broad upper anticyclone will remain in
place east of Florida Friday night and into the first part of the
weekend.  In quick succession, a series of shortwaves will eject off
of a cutoff low over southern Great Plains...but will ride the ridge
and lift well north of our forecast area, nudging it only slightly
eastward through the first half of the weekend.  In the low levels,
at least weak WAA will be ongoing Friday night on the southern side
of a surface trough axis running more or less east-to-west along
the I-40 corridor.  This trough will extend from our forecast area
southwest into the Deep South along a quasi-stationary front...and
by Saturday, one of the shortwaves lifting along it will spur
surface cyclogenesis over the Mississippi Valley.  This will allow
low-level WAA to steadily ramp up through Saturday night and Sunday.

As a result, thicknesses will remain maximized and temperatures
will remain well above normal throughout the weekend.  On Saturday,
increasing moisture and warming at the low levels will result in
decent surface-based instability, but a limiting factor could be
the presence of a capping inversion beneath the upper ridge...a
feature depicted in several operational models but not especially
favored by the latest long-range ensembles.  Even without a cap,
there won`t be much in the way of a triggering mechanism for
convection...so thinking if anything, the Blue Ridge Escarpment
and ridgelines in the Appalachians will be the only zones with a
real shot at showers on Saturday.

By Sunday, as the surface low glides over the Tennessee Valley, deep
moisture will begin building into the area from the Gulf, and will
become at least partially aligned with the better synoptic forcing.
Rainfall will begin early Sunday morning (like, before dawn)
and continue throughout the day as the front crosses the area.
Limited instability on the order of 300-600 J/kg sbCAPE looks to
develop during the afternoon, coinciding with 25-35kts of mid-
and low-level shear...so no change on the thinking that HSLC severe
event is possible, but too soon to tell with much confidence.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
As of 201 PM EDT Thursday: Cold front should cross the western
Carolinas entirely on Sunday night, with continued likely
showers overnight, and the possibility of embedded thunder with
this. PWs look to peak in the 1.5-1.75" range, but won`t be
maximized in the area where synoptic forcing will be most
pronounced...so heavy rain threat still looks like more of an
isolated issue...and the WPC Marginal Risk looks reasonable.

Strong CAA behind the front will result in rapid drying and
cooling Monday night...with temperatures likely to drop to near
freezing Monday night, and even cold Tuesday night.  Can`t rule
out a brief round of NW flow snow Monday night along the NC-TN
border...although if this were to take place it`d be short-lived
and likely not produce any impacts.  The bigger issue will be
frost/freeze potential going forward...with the entire forecast area
likely to fall to within a few degrees of freezing Tuesday night.
Dewpoint depressions, however, should be large enough that if
frost develops at all, it may be more patchy/isolated in nature.

Models diverge wildly beyond Tuesday night.  The majority keep
us dry and cool through the end of the period, but the new 12z
GFS as well as many of its ensembles bring a quick low pressure
system out of the Midwest, and give us another wetting rain late
Wednesday into Thursday.  Too soon to even speculate, though,
beyond watching for the evolution of this feature.

&&

.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
At KCLT and elsewhere: Wedge has completely eroded and a
field of SCT/BKN MVFR and low-end VFR stratocu continue to move
across the terminals. Isolated to scattered showers have developed
as well, but due to the nature of the coverage, decided to place
either a TEMPO for -RA or VCSH depending on location. South-
southwesterly winds with low-end gusts will continue through the
afternoon before the gusts and rain chances subside by sunset. Winds
remain south-southwesterly through the overnight period. Guidance
want to develop an IFR/MVFR low stratus deck into the area after 06Z
tonight across all TAF sites, with the exception of KAVL and seems
reasonable enough to put into the 18Z TAF update. Current forecast
scatters out this stratus deck by mid- to late-morning Friday with
continued south-southwesterly winds.

Outlook: IFR to MVFR cigs may linger thru Friday morning. Drier
conditions return Friday night into Saturday night before another
cold front brings shower and thunderstorm chances, and associated
flight restrictions, back on Sunday.

&&

.CLIMATE...
RECORDS FOR 04-03

               MAX TEMPERATURE         MIN TEMPERATURE
  STATION      HIGH        LOW         HIGH        LOW
  -------  ----------  ----------  ----------  ----------
   KAVL      88 1963     31 1936     64 1946     23 1936
   KCLT      90 1946     42 1915     62 1986     26 2021
                                        1946
   KGSP      87 1967     44 1901     62 2014     27 2021
                1963                                1993
                1946                                1902



RECORDS FOR 04-04

               MAX TEMPERATURE         MIN TEMPERATURE
  STATION      HIGH        LOW         HIGH        LOW
  -------  ----------  ----------  ----------  ----------
   KAVL      83 1999     33 1891     61 1893     22 1936
                1978
   KCLT      87 1999     43 1911     63 1986     29 1936
                            1899        1945
                                        1934
   KGSP      88 1963     44 1936     62 1999     25 1975
                1934



RECORDS FOR 04-05

               MAX TEMPERATURE         MIN TEMPERATURE
  STATION      HIGH        LOW         HIGH        LOW
  -------  ----------  ----------  ----------  ----------
   KAVL      86 1909     30 1891     60 2023     20 1944
                                        1910
   KCLT      88 1942     38 1891     62 1910     26 1891
   KGSP      90 1934     43 1899     60 2023     25 1904
                                        1888



RECORDS FOR 04-06

               MAX TEMPERATURE         MIN TEMPERATURE
  STATION      HIGH        LOW         HIGH        LOW
  -------  ----------  ----------  ----------  ----------
   KAVL      88 1967     36 1950     64 2023     22 1898
   KCLT      90 2010     43 1931     67 2023     28 1891
                1929
   KGSP      88 2010     47 1950     65 2023     26 1904
                            1945

&&

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

&&

$$

SYNOPSIS...MPR
NEAR TERM...CAC
SHORT TERM...MPR
LONG TERM...MPR
AVIATION...CAC
CLIMATE...