Area Forecast Discussion
Issued by NWS Greer, SC
FXUS62 KGSP 301035
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
635 AM EDT Fri Sep 30 2016
A dry southwest flow of air will linger across the region through
this weekend. Progressively warmer temperatures are on tap through
early next week. The path of tropical cyclone Matthew will be
closely watched as it tracks north near the Atlantic coast next week.
.NEAR TERM /THROUGH TONIGHT/...
As of 615 AM, a couple of convective cells linger over our northwest
NC Piedmont zones, and will move north of the forecast area shortly.
This may spell the end of convective chances for the day, but will
linger a small pop across these areas through mid-morning or so.
Mid-upper level speed max is expected to lower heights enough such
that the frontal boundary should finally nudge east of the forecast
area by early afternoon, spreading much drier air into the NC
Piedmont and northern foothills. Some of the mesoscale and short
term guidance tries to develop some ridge top convection this
afternoon, but forecast soundings look positively hostile to
convective development, so we`re not buying it. Max temps are
expected to be (finally) right around normal, except along the I-77
corridor, where maxes of a category or so above climo are still
expected. With the dry air mass in place, all areas are expected to
see around to a little below climo min temps tonight.
.SHORT TERM /SATURDAY THROUGH MONDAY/...
At 240 AM Friday: GFS and ECMWF indicate that the center of a H5
closed low will lift north across the Great Lakes region this weekend. The
mid level pattern across the region will likely feature a Bermuda
High and a trof from the Ohio River valley south to the Mississippi
Delta. Short range guidance shows that a dry slot associated with
the Great Lakes low will rotate across the western Carolinas. This
pattern should result in dry conditions and high temperatures
ranging from the mid 70s within the mtn valleys to the low 80s east.
On Monday, it appears that an asymmetrical mid-level omega block
will develop over the northern CONUS, with the ridge axis over the
Mid West and Great Lakes. TC Matthew is expected to be tracking
north near the eastern tip of Cuba by late Monday. Sensible weather
across the CWA will remain unchanged from the dry weekend. High
temperature are forecast to warm a degree or two over values reached
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
As of 250 AM Friday: The path of TC Matthew will gain most of the
attention through the extended period. Both the GFS and ECMWF
indicate that Matthew will track north, tracking parallel along the
Atlantic coast from FL to NC. To the west, the northern tip of a H5
ridge will reach the southern Appalachians, sourced from a high over
Mexico. To the north, another deep low is expected to organize
across the nrn plains. The pattern does not appear to be supportive
of heavy rainfall across the CWA, developing ahead or west of
Matthews track. I will keep the forecast generally dry from Tuesday
through Thursday. Temperatures are forecast to remain between 3 to 5
degrees above normal.
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
At KCLT and KHKY, surface front remains virtually stalled just west
of the terminals this morning, with plenty of low level moisture
supporting LIFR cigs at KHKY, and should support at least tempo IFR
cigs at KCLT through bout 14Z. MVFR visby restrictions also
anticipated to continue at KHKY and will be possible at KCLT. The
front is expected to finally punch through by late morning, so
improvement to VFR should occur quickly, with VFR conditions
persisting through the end of the period. S/SW winds of 7-10 kts are
expected to develop by afternoon.
Elsewhere: With drier air lingering behind frontal boundary, all
sites are forecast to see VFR conditions persist for the next 24
Outlook: VFR conditions expected in most places through the
beginning of next week as dry high pressure settles in over the area.
10-16Z 16-22Z 22-04Z 04-06Z
KCLT Med 69% High 100% High 100% High 100%
KGSP High 100% High 100% High 100% High 100%
KAVL High 85% High 100% High 100% High 100%
KHKY High 85% High 100% High 100% High 100%
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: