Area Forecast Discussion
Issued by NWS Greer, SC

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FXUS62 KGSP 220003

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
803 PM EDT SAT MAY 21 2016

Dry high pressure builds into our region from the Mississippi and
Ohio valleys from Sunday into the start of the week as low pressure
lingers over the mid Atlantic.  A moist southerly flow develops by
mid week and continues into the weekend.


As of 800 PM...The line of storms in the Charlotte metro area is
beginning to organize a little push of outflow toward the SE. So I
expect this activity to clear the remaining SE corner of the CWFA
within the next hour or so. Otherwise, the radar looks fairly quiet,
as dry air starts to filter in from the NW. Another adjustment to
the PoPs will be done with the next update.

Later this evening...a few weak showers may linger along/near
the TN border, as the rest of the activity wanes. Lows tonight are
forecast to range in the low 50s across the mtns to upper 50s east.

Sunday...High pressure will build in across the the high
remains centered over the Mississippi River Valley. However...H5
closed low centered over VA will continue to support generally moist
NW flow across the west facing mtn slopes. Clouds and ISO showers
will remain in the forecast through Sunday. Elsewhere...dry
conditions with gusty NW winds will be featured in the forecast.
High temps should range from upper 60s within the mtn valleys to mid
to upper 70s across the upper Savannah River Valley.


As of 200 PM Saturday...the early part of next week will be
dominated by an upper low that should move off the Mid-Atlantic
coast Sunday night and Monday, then slowly rotate up to the New
England Coast on Tuesday. The western Carolinas will be under the N
flow part of the circulation into Tuesday, so other than some
lingering showers on the TN border Sunday evening, it should be dry.
The plume of better moisture rotating around the upper low is
expected to be just east of the fcst area on Monday. A few showers
may nick part of the NW Piedmont on Monday as some of the lingering
instability underneath the mid-level cool pool will be close by.
After that, think it should be dry as the low moves away Tuesday and
a flattening upper ridge builds in from the west Tuesday night.
Temps should moderate through the period...back to just below normal
on Monday...and then a few degrees above normal on Tuesday.


As of 235 PM Saturday, 500mb flow has a ridge axis from Mobile Al
to KY on Wednesday with surface high pressure shifting to the east
and off the east coast.  Moisture will be increasing slowly from the
west on south to southwesterly low level flow. Instability is rather
low Wed PM with 600 CAPE near Fontana Lake on the GFS model and
lower on ECMWF.  Moisture and instability will increase Thursday
into Friday as the much higher CAPEs remain near and west of
Mississippi River.  CAPE of 1000 to 1500 across our area Thursday PM
and even a bit higher Friday PM on GFS. Best CAPE on ECMWF on Thurs
PM with around 1600 late day.  Not much change in grids from
previous forecast. Low level flow becomes more SE going into next
weekend as ridge will be centered off the mid Atlantic Coast. This
would introduce an upslope component.

Max Temps a few degrees above normal with Highs in the 80s for all
elevations below 2500 feet. Mins mostly in the 60s.


At KCLT...A cluster of TSRA will slowly push east of the terminal
over the first hour of the 00z taf period. Will highlight with a
tempo. Winds will be quite VRB during that first hour due to various
outflows. Winds will begin to favor a N/NW direction by 2z, with
some lingering mid LVL clouds into tonight. On Sunday...a mid level
trough will swing thru overhead, which will help mix some gusts out
of the NNW and produce a scattered VFR cumulus deck. There may be a
few showers develop to the east in the AFTN, but CLT should stay dry.

Elsewhere...A stray shower or two may linger into the early evening,
but otherwise precip should be confined to NW flow upslope areas
near the TN border. So will go with a dry FCST at all the TAF sites.
Some up-valley moisture within that flow may produce an IFR CIG at
KAVL for part of the pre-dawn hours. Otherwise, VFR conditions are
expected as dry air continues to filter in from the N. Gusty winds
possible off and on at KAVL overnight, then at all sites Sunday AFTN
out of the NNW.

Outlook: Conditions should gradually dry out Sunday and Monday. AFTN
showers and TSTM chances may return on Wednesday.

Confidence Table...

            00-06Z        06-12Z        12-18Z        18-00Z
KCLT       High 100%     High 100%     High 100%     High 100%
KGSP       High 100%     High 100%     High 100%     High 100%
KAVL       Med   74%     Med   63%     High  94%     High 100%
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 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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