Area Forecast Discussion
Issued by NWS Greer, SC

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FXUS62 KGSP 012045

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
445 PM EDT FRI JUL 1 2016

An upper trough will push a cold front south across the region
through Saturday.  The front will stall just to the south of the
area, but then will lift slowly back north late in the weekend into
the beginning of next week.


As of 430 PM: Convection has remained isolated so far, despite
quite unstable conditions shown on SPC Mesoanalysis (1500-2000 J/kg
of SBCAPE). This all ahead of the shortwave trough axis that is
pushing across the Appalachians this afternoon. Very dry dewpoints
in place across the mountains behind the upper trough axis, making
for quite the comfortable afternoon up there, though not quite so
much across the Piedmont. However, because of the morning cloud
cover, temperatures have been a bit slower to climb this afternoon.
Despite the surface environment being fairly conducive for strong
convection across the Piedmont (plus dCAPE over 1000), midlevel
lapse rates are not at all supportive. An isolated severe storm
could still develop, but generally the HRRR depiction of sparse
coverage and gradual propagation toward the Midlands appears

Any convection should rapidly dissipate this evening with the exit
of the upper trough, and the dry air across northwest zones will
certainly try to make it farther south, but as the flow flattens
tonight the front will stall across the area making the attempt
of dry air intrusion futile across most of the Piedmont, with not
much change in overnight lows from what we`ve been seeing.

The front will sort of stall and then wash out across the area
Saturday, and with a shortwave approaching from the west (more on
that below), should see a decent increase in instability across the
area with just a bit of an enhancement to the normal summertime
diurnal pattern, with initial convection over the mountains
but possibly increasing in coverage across the NC Piedmont in
closer proximity to the upper forcing. Thermodynamics tomorrow
look similar to today but with just slightly stronger flow aloft
could see a bit of jet-level synoptic lift, and thus the SPC Day2
Marginal Risk for eastern zones looks reasonable. Highs Saturday
are progged to be a degree or two warmer than those today.


As of 230 pm EDT Friday: Mid level ridging will be in place to the
south of the area through this period, keeping conditions warm and
muggy. The southern end of the westerlies will allow weak
disturbances in the flow to kick of mainly afternoon and evening
showers and thunderstorms. As usual, initiation will begin across
the higher terrain then pushing into the Piedmont during the late
afternoon and evening. High temperatures will be in the lower 90s
outside the mountains with heat indices reaching the mid to upper
90s each afternoon. Lows will likely remain above 70 degrees outside
the mountains.


As of 230 pm EDT Friday: Weak troffing will develop during this
period across the region allowing for a general increase in shower
and thunderstorm activity. The peak in the activity will be in the
typical late afternoon/evening but overnight activity should
increase during the period as well. Conditions will remain hot and
muggy with heat indices approaching 100 outside the mountains before
storms cool it off each day.


At KCLT and elsewhere: VFR this evening and any -SHRA/TSRA should
be isolated at best.  Should see another round of mainly MVFR fog
Saturday morning, and current guidance not indicating low cigs,
though any areas where soaking rains occur this aftn could see
some issues. SW winds this afternoon will veer around the compass
tonight as a front pushes in but should be pretty light, settling
from the NE by sunrise and possibly continuing around to SE by
the end of the period. Introduced PROB30 TSRA for KCLT/KAVL/KHKY
as another shortwave approaches, but chances too low through 18z
Sat for the SC sites to introduce with this set of TAFs.

Outlook: Diurnal convection expected to return to typical summertime
coverage Saturday.  Another series of fronts, and potential weak
low pressure systems riding along the fronts, appears on tap
for Sunday through Tuesday.  This period may offer an enhanced
thunderstorms possibilities.

Confidence Table...

            20-02Z        02-08Z        08-14Z        14-18Z
KCLT       High 100%     High 100%     High  95%     High 100%
KGSP       High 100%     High 100%     High 100%     High 100%
KAVL       High 100%     High 100%     High  83%     High  91%
KHKY       High 100%     High 100%     High  83%     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 schedule TAF issuance flight rule category. Complete hourly
experimental aviation forecast consistency tables and ensemble forecasts
are available at the following link:




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