Area Forecast Discussion
Issued by NWS Greer, SC

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FXUS62 KGSP 250250

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1050 PM EDT SUN JUL 24 2016

Broad high pressure will linger over the region through the week
before a mid level disturbance crosses the forecast area on Friday.
Moisture levels will gradually increase across the western Carolinas
and northeast Georgia by the middle of the week while a stationary
front remains across the mid Atlantic region.


As of 1040 PM EDT:  Once again the previous lowering pop trend was
favored as convection has cleared out across the region leading
into a partly cloudy, becoming mostly clear evening as mid/high
clouds advect downstream.  That combined with ample bl moisture and
calm winds will lead to patchy fog once again, with the most dense
fog being in the mountain valleys where visbs could fall to less
than a 1/2sm at times.  Other than that, expecting a rather quiet
evening, thus no sig changes were needed/made with this update.

Previous Discussion:  A zonally-oriented 594 dm 500 mb ridge will
remain over the region through Monday. Any lingering late evening
convection will quickly diminish and we will see another night
of mild min temps 4 to 8 degrees above climo along with mountain
valley stratus and fog. Scattered convection will develop in the
mountains again on Monday afternoon - with similar coverage to
today. A persistent surface lee trough will keep winds light S
to SW through the period except a bit more westerly across the
mountains. Expect plenty of mid 90s maxes Monday afternoon, but
with heat index values likely peaking at 101 to 103 again in the
lower piedmont. Southern Elbert County and Eastern Union County
NC will be the closest to approach 105.


At 210 PM Sunday: On Monday night and upper ridge will centered off
the coast of the Carolinas, extending west and inland to the
southern Appalachians. Although the ridge remains in place off the
coast through Wednesday, there are some indications that falling
heights to our north may reach as far south as northern NC.

At the surface, weak troughing will be in place Monday night along
the eastern seaboard, while a weak cold front drops south over the
OH River Valley. The front slows to our north on Tuesday, while
moisture ahead of the boundary increases over the southern
Appalachians. By Wednesday there is some discrepancy in the models
on the position of the front, with some indications it will reach NC
or even northern SC, brining even more moisture to the area.

Instability will be sufficient to support convection through the
period, perhaps lingering overnight depending on models sources, but
shear appears to be limited and not supportive of organized
convection. Steering flow appears weakest during daylight hours, at
least at lower levels, perhaps supporting slow moving cells and
locally heavy rainfall. Temperatures will run three to five degrees
above normal. Apparent temperatures do not appear to exceed 100


As of 210 PM Sunday...Good confidence is had in the ext range as the
op models continue in agreement with the ulvl pattern and to some
extent the lower levels. The ECMWF builds the subtrop ridge farther
west than the GFS across the nrn GOM...however moisture flux
differences will not appreciably affect the sensible wx. Broad flat
ridging will dominate the srn CONUS Thu with gradually lowering
heights across the east through the period as a broad H5 trof swings
across the Glakes region. This trof will push a weak cold front
toward the area by Fri and the airmass ahead of the front will
remain seasonably warm and moist. Likely pop coverage will favor the
NC mtns through the period with pulse stg/svr tstms developing each
afternoon. Slight to sct mention will be maintained non/mtns. The
persistent synoptic pattern will maintain max/min temps a few
degrees F above normal each day.


At KCLT:  VFR through the period as deep layer ridging prevails
keeping any convection at bay across the NC piedmont.  Few/sct llv
cu will persist for a few more hours before sct out to only high
level cirrus through the remainder of the evening.  Pretty much a
repeat on Monday as the llv lapse rates increase leading to llv
cu development with heating.  Winds through the taf cycle will
remain light/moderate and southerly.

Elsewhere:  VFR through the vast majority of the taf cycle with the
exception of persistence ifr fog/cigs in the mtn valleys as well
as mvfr fog possible at KHKY by morning.  Otherwise, few/sct low
cu to persist for the next few hours clearing to only high cirrus
at the SC sites.  Any restrictions will lift by mid/late morning
leading into developing and thickening llv stratocu, especially on
the periphery of the ridge across the mtns/fthills sites as well
as KAND.  Consequently, it is those locales that favor the best
tsra potential thus vcts was included.  Winds will remain light
and southerly tonight, increasing into the 6-8kts range during
best mixing on Monday

Outlook: Isolated/scattered afternoon/evening showers and
thunderstorms will continue across the mountains/piedmont through
much of the week - with coverage increasing a bit each day. Morning
fog and low stratus will continue in the mountain valleys around
daybreak each day, and also be possible in locations that receive
heavy rainfall the preceding afternoon/evening.

Confidence Table...

            03-09Z        09-15Z        15-21Z        21-00Z
KCLT       High 100%     High 100%     High 100%     High 100%
KGSP       High 100%     High  94%     High 100%     High 100%
KAVL       High 100%     Med   60%     High 100%     High 100%
KHKY       High 100%     High 100%     High 100%     High 100%
KGMU       High 100%     High 100%     High 100%     High 100%
KAND       High 100%     High  83%     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:



  STATION      HIGH        LOW         HIGH        LOW
  -------  ----------  ----------  ----------  ----------
   KAVL      92 2010     68 2000     70 2012     51 1895
                2005                    2011
                1987                    2010
   KCLT     101 2010     69 2000     79 2010     62 1947
   KGSP     100 1995     72 2000     77 2010     57 1911




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