Area Forecast Discussion
Issued by NWS Greer, SC

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

FXUS62 KGSP 300201

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1001 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.


0200 UTC Update: Pops and QPF were adjusted per radar trends,
favoring the Interstate 40 corridor where greatest convective
coverage was noted. Winds were updated with a blend of the latest
NAM and ADJMAV. Only minor changes were made to overnight

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
the boundary.


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.


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.


At KCLT: VFR. Winds will favor the WNW overnight, then back to SW on
Saturday. Low VFR cigs are possible, mainly this evening and
Saturday afternoon. Convective chances will be Saturday afternoon.

Elsewhere: Other than daybreak cig and vsby restrictions at KAVL, VFR
is expected. Low VFR cigs are possible at all sites, mainly this
evening and again Sunday afternoon, especially in NC. Winds will
favor the W overnight in the foothills, backing to the SW on
Saturday. Winds will favor the NW at KAVL. Convective chances will
be best this evening and late Saturday.

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

Confidence Table...

            01-07Z        07-13Z        13-19Z        19-00Z
KCLT       High 100%     High 100%     High 100%     High 100%
KGSP       High 100%     High 100%     High 100%     High 100%
KAVL       High 100%     Med   76%     High  92%     High 100%
KHKY       High 100%     High  90%     High 100%     High 100%
KGMU       High 100%     High 100%     High 100%     High 100%
KAND       High 100%     High  96%     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:




AVIATION...JAT is the U.S. government's official web portal to all federal, state and local government web resources and services.