Area Forecast Discussion
Issued by NWS Greer, SC

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574
FXUS62 KGSP 281050
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
650 AM EDT THU JUL 28 2016

.SYNOPSIS...
Broad surface high pressure will linger over the Southeast, while a
surface low tracks along a stationary front across the Mid-Atlantic.
This front may finally sag south into our area early next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 650 AM: I will update the forecast to decrease mention of fog
within the mtn valleys. Otherwise, the current forecast appears in
good shape.

As of 350 AM: Short range models indicate that a mid level short
wave will slowly ripple east across KY/TN today. Guidance indicates
that a band of SHRAs and TSRAs will develop along and ahead of the
S/W across eastern KY/TN. Coverage of convection will gradually
increase across the southern Appalachians during the mid to later
afternoon. Forecast soundings east of the mtns indicate weak capping
will remain through the afternoon, limiting coverage to isolated.
Deepening sfc low pressure across VA should yield a 2-3 mb pressure
gradient across the CWA this afternoon. The combination of afternoon
mixing and the shallow gradient should result in a period of
marginal gusts from the SW. Moderate instability and weak shear may
support a few svr storms.

Sunny conditions and llvl downslope winds will result in steady
warming through mid day. Given very mild morning low temperatures,
noon time temps could easily range in the low 90s east of the mtns.
High temperatures are forecast to peak from the upper 80s across the
mtn valleys to the mid to upper 90s east. The hottest temperature
should exist east of I-77, under 22c H85 temps, with values around
98. Similar to Wednesday, the combination of hot temperatures and
RH values 43 to 45 percent should result in Heat Index to peak at or
above 105 F. We will issue a Heat Advisory for Davie south the Union.

Tonight...I expect that convection will linger across the mtns ahead
of the mid level S/W. Schc PoPs will remain across the mtns. It
should be another mild night, min temps forecast ranging around 3 to
5 above normal.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
As of 300 AM Thursday...There will be little change in the pattern
for Friday and Saturday. A weak and shallow trough will continue to
produce a weakness in the subtropical high over the lower to
mid-Mississippi Valley. A surface wave will pass east of the area by
Friday morning, and the low-level flow will take on a more west to
west-southwest direction. This will result in some downslope
influence east of the mountains. Despite this, models show a
continued gradual decreasing trend in low-level thicknesses. Highs
will still by about 3-5 degrees above normal both days. Convection
will continue to favor the mountains, as usual. The downslope may
limit Piedmont convection. On Friday, most of the operational models
show a lack of convective response with the Piedmont/Lee trough. But
with a westerly steering flow, some of the mountain convection
should push off to the east. Saturday`s PoPs look a little higher,
as moisture increases ahead of another wave streaking through the
Ohio Valley. Overall, lack of shear and forcing should result in
continued pulse mode with an isolated microburst threat. Dew points
should mix out enough to preclude any heat index headlines, but HI`s
will continue to be in the upper 90s to around 104, both afternoons.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
As of 315 AM Thursday...The weakness in the upper-level subtropical
ridge will gradually drift east from the Mississippi Valley to the
East Coast by Tuesday. A quasi-stationary front will gradually sag
south into the area Monday into Tuesday and gradually wash out
Wednesday. So the medium range forecast will feature slightly above
climo PoPs and temps about a category above normal. This pattern
will hopefully provide more widespread rain to ease the drought.

&&

.AVIATION /12Z THURSDAY THROUGH MONDAY/...
At KCLT and elsewhere: Short range models indicate that a mid level
short wave will slowly ripple east across KY/TN today. Guidance
indicates that a band of SHRAs and TSRAs will develop along and
ahead of the S/W across eastern KY/TN. Coverage of convection will
gradually increase across the southern Appalachians during the mid
to later afternoon. Forecast soundings east of the mtns indicate
weak capping will remain through the afternoon, limiting coverage to
isolated. Deepening sfc low pressure across VA should yield a 2-3 mb
pressure gradient across the CWA this afternoon. The combination of
afternoon mixing and the shallow gradient should result in a period
of marginal gusts from the SW. KAVL may see MVFR up valley stratus
develop late tonight, mainly after 8z.

Outlook: Falling heights aloft and the arrival of gulf moisture will
support increasing chances of precipitation and perhaps associated
restrictions going into the weekend.

Confidence Table...

            11-17Z        17-23Z        23-05Z        05-06Z
KCLT       High 100%     High 100%     High 100%     High 100%
KGSP       High 100%     High 100%     High 100%     High 100%
KAVL       High 100%     High 100%     High 100%     High 100%
KHKY       High 100%     Low   55%     High 100%     High 100%
KGMU       High 100%     High 100%     High 100%     High 100%
KAND       High 100%     Low   55%     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:

www.weather.gov/gsp/aviation

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...Heat Advisory from noon today to 8 PM EDT this evening for
     NCZ037-057-072-082.
SC...None.

&&

$$
SYNOPSIS...ARK
NEAR TERM...NED
SHORT TERM...ARK
LONG TERM...ARK
AVIATION...NED



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