Area Forecast Discussion
Issued by NWS Greer, SC
FXUS62 KGSP 291727
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
127 PM EDT Thu Sep 29 2016
A stationary front will remain across the Midlands of South Carolina
and central North Carolina today. Meanwhile, an upper level low will
drop south into the Ohio Valley and linger there through the end of
.NEAR TERM /THROUGH FRIDAY/...
As of 956a EDT Thursday: Latest mesoanalysis has a triple-point low
just west of Charlotte, with a cold front as defined by surface
moisture gradient curving towards the northwest and southwest from
there, and a warm front towards the east. Airmass east of the front
is somewhat unstable with CAPE currently around 1000 j/kg, and
likely to increase with afternoon heating. With strong upper
system, deep layer shear along the cold front is around 50 kts, and
less ahead of the front. The combination of shear and instability
is of some concern today over the extreme eastern parts of the CWA,
and western North Carolina, though the moist sector will continue to
edge eastward during the day. While capping dosen`t look that
strong, main problem with any convection is that initiation may be
well east of the area as fronts progress during the day.
Mesoanalysis already shows line of best surface moisture convergence
well east of the area, well ahead of the dewpoint gradient. CAMS are
not at all enthusiastic about the prospects of strong storms this
afternoon, with both the NCAR and SPC SSEO having practically no
strong updrafts this afternoon in the CWA. If any convection does
develop this afternoon, it is most likely along the warm front where
moisture convergence is slightly better, with fast northeast storm
motion and the prospect of severe events. SPC forecast has a
marginal risk for this afternoon over the eastern 6 counties of the
Fog over eastern counties is gradually beginning to lift, and should
disperse over the next hour.
Temperatures will be trending cooler behind the front and down
towards seasonal normal for a change.
.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/...
As of 230 AM EDT Thursday...The large upper low will wobble/meander
over the Ohio Valley during the Short Term, keeping the CWFA under a
pronounced dry slot on its SW side. Given the trend in the upper low
track, thicknesses don`t fall as much as previous model runs had
suggested. So temps were nudged up slightly for Friday and Saturday.
Max temps will be about one or two categories above normal (except
slightly cooler in the western half of the NC mountains). Min temps
will be around normal. Dry conditions are expected and skies should
be mostly clear thru the period, but the stalled front will linger
just to our east on Friday.
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
As of 130 PM EDT Thursday...It doesn`t look like any changes will
need to be made to the inherited dry and warm fcst to start off the
workweek with the medium range model consensus continuing the deep
and dry wsw flow aloft atop the region. Monday`s max temperatures
are slated to be two to three categories above the early Oct climo.
Even into Tuesday, the effectively dry wx should remain with max
temperatures perhaps a few deg F less warm than persistence within
the tightening easterly flow between TC Matthew and moderately
strong sfc hipres center over New England. For the latter half of
the period, at this stage of the game, any notable affects of
Matthew are progged to be well se/e of the cwfa. So, sensible wx
remains dry and warm for Wed/Thu, with the potential for breezy
easterly and/or northerly winds given the continued strength of
the pressure gradient.
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
As of 1:15pm EDT:
At KCLT, deck of stratus at 015 has held in until now, but with
improving satellite presentation, expect this to lift in the next
hour or so. For the rest of the day, there is some chance for
convective activity with a triple point frontal intersection to the
southeast and an occluded front stretching northwestward over KCLT.
Expect most convection to be along the main frontal boundaries well
to the east, but some activity is possible in the vicinity of the
occluded front, and latest radar to the north which could further
develop down towards KCLT. Currently have VCSH in the TAF, given
less than 30 POP for the area. Otherwise, easterly to southeasterly
winds will gradually veer to the south by tomorrow morning.
Elsewhere: A few areas in North Carolina have some lingering low
CIGs which look on satellite to be breaking-up over the next hour.
Some convection is also possible this afternoon, primarily near the
KHKY and KCLT sites as a weak occluded front stretches over the area
from a frontal intersection over southeastern South Carolina. Main
convective activity is expected south and eastward along the main
fronts, but radar has some activity, that rapidly moves
northeastward, east of KHKY. KHKY and KAVL may also see some fog in
the morning with residual surface moisture, especially any areas
receiving rain today.
Outlook: Dry high pressure will build in slowly behind the front,
which should bring VFR conditions in most places through the
beginning of next week.
17-23Z 23-05Z 05-11Z 11-12Z
KCLT Med 75% High 100% High 100% Med 75%
KGSP High 100% High 100% High 100% High 100%
KAVL High 100% High 100% Low 55% High 81%
KHKY High 87% High 100% High 100% Low 44%
KGMU High 100% High 100% High 100% High 100%
KAND High 100% High 100% High 100% High 100%
The percentage reflects the number of guidance members agreeing
with the scheduled TAF issuance flight rule category. Complete hourly
experimental aviation forecast consistency tables and ensemble forecasts
are available at the following link: