Area Forecast Discussion
Issued by NWS Greer, SC

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FXUS62 KGSP 151049

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
649 AM EDT Sun Sep 15 2019

A cooler wedge of high pressure will remain over the area through
the end of the weekend before hot temperatures return again early
next week. Isolated showers and thunderstorms are possible early in
the week before conditions become cooler and drier by the end of
the week.


As of 630 AM EDT Sunday: Grids are in good shape this morning. Made
updates to hourly T/Td trends, but nothing major. Other updates are
for aviation parameters.

Otherwise, wide upper ridge remains in place over the South, with
Humberto working his way north of the Bahamas this morning. The
pattern will amplify through the day as troughing builds along the
Pacific Coast as well as over the Hudson, stretching down the East
Coast, as the upper ridge is forced to retreat over the middle of
the country. With the upper ridging, a warm nose at about 800mb will
be in place today, generally capping most of the area and preventing
any convective development, but mechanical lift across the mountains
will allow for some isolated to widely scattered convection this
afternoon, possibly spreading into the NC Piedmont. For
temperatures, the heat will begin returning today with afternoon
highs a good 5 or so degrees above normal, and little change to
overnight lows.


As of 340 AM EDT Sunday: With TC Humberto churning offshore of the
FL/GA/SC coast on Monday, stretched sfc high pressure from the
western Carolinas to WV/VA will continue to erode Monday into
Tuesday, as upper ridging over the central CONUS slowly pushes
eastward. While conditions are expected to remain dry with well
above normal temperatures on Monday, latest guidance suggests a weak
front/troughing feature that may bring isolated showers and
thunderstorms to the area on Tuesday. Temperatures will remain well
above normal on Tuesday, as well.


As of 355 AM EDT Sunday: The extended forecast period kicks off mid-
week, as latest guidance continues to prog TC Humberto well away
from the Southeast coast, slowly tracking up the east coast (again,
well offshore with no impact to the US attm). Meanwhile, upper
ridging will continue to shift to the east coast while sfc high
pressure now over the northeast builds southward into the southeast,
where it`ll remain through the rest of the week and into the
weekend. With wedge of high pressure in place for the extended
forecast period, expect temperatures to hover around normal
Wednesday through Friday, with a slight warming trend on Saturday.
Available moisture and forcing continues to be non-impressive, thus
anticipate convection to be limited and mainly to the NC mountains.


At KCLT and elsewhere: Mountain valley fog remains dense this
morning, spreading into the NW NC Piedmont. KAVL and KHKY both have
seen LIFR to VLIFR through the overnight hours, but expect
improvement over the next couple of hours. Area of low VFR to MVFR
cigs moving south toward KCLT may bring temporary restrictions as
well. Otherwise expect VFR cu to develop this afternoon, and TSRA
chances are too low to mention with any certainty at any sites, with
KAVL having the best chances. Guidance hints at additional
restrictions in the morning and have introduced this at KAVL and
KHKY. NE winds through the period, a little more N to NNW at KAVL.

Outlook: Fairly quiet weather is expected this week with VFR
prevailing. The mountain valleys will be the exception in the early
morning hours, with low stratus and fog a strong possibility around
daybreak each day.

Confidence Table...

            10-16Z        16-22Z        22-04Z        04-06Z
KCLT       Med   75%     High 100%     High 100%     High 100%
KGSP       Med   79%     High 100%     High 100%     High 100%
KAVL       Low   59%     High 100%     High 100%     High  83%
KHKY       Low   55%     High 100%     High 100%     High 100%
KGMU       High 100%     High 100%     High 100%     High 100%
KAND       High  91%     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:




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