Area Forecast Discussion
Issued by NWS Greer, SC
FXUS62 KGSP 291838
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
238 PM EDT FRI JUL 29 2016
A pretty typical mid-summer weekend is on tap for the region as
a broad and weak pressure pattern lingers atop the Southeast.
Little change in the weather pattern is expected through the start
of next week.
.NEAR TERM /THROUGH SATURDAY/...
As of 2:25pm EDT Friday: Conditions will remain generally the same as
recent weeks, with seasonally warm morning lows, high humidity and
temperatures above normal with chances for afternoon thunderstorms,
and mostly light winds.
Upper trough west of the area has become somewhat broad this
afternoon and is expected to change little over the next 24 hours,
except for some eastward movement of the main axis. Meanwhile, lee
surface trough has a closed low east of NJ and has moved eastward
some this afternoon with more northwesterly flow in areas east of
I26. Lower dewpoints associated with the northwesterly flow has
reduced CAPE over eastern parts of the CWA to 500 j/kg versus over
1000 elsewhere. Edge of better moisture to the south functions as a
weak boundary east-west across the CWA. This boundary may help
focus afternoon convection in piedmont areas this afternoon as some
light convection already exists along it from Laurens to Anderson.
The other focus for convection will be the higher terrain areas of
western North Carolina. Wind shear this afternoon is weak, with low
CAPE and forcing, thus little strong convection is expected. Any
shower activity should decline diurnally after dark. With mesoscale
boundary across the area, blended in CAM POPs into the forecast,
which made for higher POPs over western areas on the warm side of
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
As of 230 PM Friday...looks like we are still on track for a
breakdown of the subtropical ridge over the southeastern US for the
early part of next week. The models have the pattern slowly evolving
on Sunday with the axis of a broad upper trof approaching and then
moving across the region in the afternoon and evening. The extra bit
of mid/upper forcing should provide for a slightly more healthy
environment for deep convection for Sunday afternoon and then again
on Monday, so the forecast will feature slightly higher precip
chances than the last few days. The activity will be mainly diurnal
in nature and typical for the time of year, initiating over the mtns
during midday and then moving out over the Piedmont in the evening.
Cannot rule out a few strong/severe storms both days, but poor lapse
rates and weaker dCAPE suggest little chance of that happening.
Temps will remain above normal by a few degrees, but a few degrees
less than this past week. Still warm, but not anywhere close to an
advisory. In short...not much more than typical summer weather.
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
As of 215 PM Friday...not much to get worked up about through next
week, as it looks like typical summertime weather. The upper pattern
gradually evolves from a weak upper trof on the East Coast early
in the week to a weak upper ridge expanding eastward from the Plains
late in the week. The trof axis should be to the east on Tuesday,
resulting in an unfavorable NW downslope flow E of the Blue Ridge,
and a surface boundary perhaps to our east. Thus, at first glance
Tuesday might have the least chance of precip. That changes for
mid-week as we get enough moisture return to allow for scattered
mainly diurnal showers and storms each day through Friday. Temps
should warm back to the mid-90s for mid- to late-week, altho this
should not threaten any records or suggest any heat advisories.
.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
At KCLT: Winds have been WNW this afternoon, but may deviate at
times to WSW in afternoon mixing. Surface trough with closed low
east of NJ has backed winds to more northerly. This wind backing
has a downslope component which has reduced dewpoints some as well.
Reduced moisture will reduce the already limited chance for a shower
this afternoon, though soundings still have enough moisture at
around FL060 to include clouds at that level.
Elsewhere: Weak surface trough east of the Appalachians has sagged
southeast in areas east of I26 in response to closed low portion of
trough east of NJ. Overall, winds are light at 5 to 10kts with wind
direction fluctuating from WSW to WNW in eastern areas and more
generally WSW in western areas. WSW winds are associated with some
drying and a reduced chance for showers this afternoon. Areas
generally west of I26 still have a chance for a shower or
thunderstorm this afternoon, with some convection activity currently
on radar near KAND. Some patchy fog is possible Friday morning,
especially in the most isolated mountain valleys.
Outlook: Broad troughing to move across the east/central CONUS
through the weekend into next week. Moisture in the low/mid
levels combined with a series of impulses working through the mean
flow aloft will yield continued/increased chances for shra/tsra
into/through the start of the new work week. As such, restrictions
associated with shra/tsra are possible, as well as early morning
18-24Z 00-06Z 06-12Z 12-18Z
KCLT High 100% High 100% High 100% High 100%
KGSP High 100% High 100% High 100% High 100%
KAVL High 100% High 100% High 88% High 94%
KHKY High 100% 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: