Area Forecast Discussion
Issued by NWS Greer, SC

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FXUS62 KGSP 220604

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
204 AM EDT FRI JUL 22 2016

Bermuda high pressure and upper level ridging will remain in control
of the weather over the next few days. This will result in well
above normal temperatures...before a weak cold front pushes in from
the north early next week.


As of 150 AM, convection has completely dissipated and no additional
activity is anticipated through the early morning hours, so pops
have been reduced to less than slight chance. Patchy fog and low
stratus is expected to gradually expand this morning, mainly in the
mtn valleys and in areas that received heavy rain Thu

Otherwise...a broad upper ridge will remain centered over the
southern plains through Friday while a trough axis lingers just off
the Atlantic coast. A little less in the way of upper energy moving
southward east of the ridge into the Carolinas is expected on
Friday. Convection will develop later in the day and primarily over
the higher ridges mid afternoon - with some survival into the
adjacent foothills or perhaps piedmont toward evening. Better
insolation, weak downsloping flow, and less moisture in profiles
should lead to higher temps Friday afternoon than Thursday. More
dewpoint mixout is possible as well, so heat index values should be
capped around 100 in the hottest areas.


At 130 PM Thursday: On Friday night and upper ridge will build east
front the plains across the southern Appalachians, completely
covering our area by late Sunday. Before this ridge overspreads the
area, weak lobes of vorticity may move southeast over the mountains
on the west side of a coastal trough. The models show modest
instability and weak shear each day, supportive of convection, but
not organized storms. Weak steering flow may support locally heavy
rainfall however, especially if cell can train over the same areas.
Temperatures will warm from around 3 degrees above normal to around
6 degrees above normal. Lingering moisture will allow apparent
temperatures to approach 102 degrees in the upper Savannah River
Valley on Friday, and 100 to 105 degrees from the foothills to the
Piedmont on Saturday.


As of 115 PM Thursday...Not much change needed to the going fcst.
Strong ulvl ridging will continue into Mon then slowly break down as
a couple H5 s/w trofs swing across the Glakes region. This will
bring a sfc front into the fcst area late Mon or early Tue. With
little flow aloft this front will become stationary and reinforced
somewhat on Thu as another weak bndry settles in from the north. As
far as the sensible wx goes...sct to num afternoon showers and
thunderstorms will be the norm...esp across the higher
enhanced llvl lift provides broad focusing in a moderately unstable
yet low sheared environment. Max temps were brought down a degree or
two most locale Mon with increasing cloud cover possible...however
heat index values shud still reach adv levels across the srn half of
the CWFA. With weakening in the upper heights and lessening deep
layered subs...max temps will return closer to normal levels Tue
through the period.


At KCLT: The main concern in the very near term is the fog potential
early this morning, which appears to be higher than in recent days.
Based upon the latest observational trends, opted to include a tempo
for 4SM for a couple of hours before sunrise. Otherwise, light S/SW
winds will persist through the period. Isolated convection is
expected across the Piedmont by this evening, but chances appear to
be lower than yesterday, so convection is omitted from the forecast
for now.

Elsewhere: Expect fog/low stratus to form around KAVL by 09-10Z.
Otherwise, MVFR visby restrictions are expected at KHKY, KGSP, and
esp KAND, where the ground is wet due to significant rainfall on
Thursday. In fact, added a tempo for IFR visby and FEW004 at KAND.
Also would not rule out some brief stratus and IFR visby at KGSP and
KHKY, but feel that MVFR is the most likely outcome. Convection is
expected to develop across the high terrain once again this
afternoon, and to move almost due south. PROB30s for TSRA are
carried first at KAVL, then at the Upstate SC terminals during the

Outlook: Expect typical midsummer weather with scattered afternoon
and evening showers and thunderstorms through the early next
week. Morning fog and low stratus will be possible each day in
the mountain valleys and also in locations that receive heavy
rainfall the preceding afternoon/evening.

Confidence Table...

            06-12Z        12-18Z        18-24Z        00-06Z
KCLT       High  97%     High  97%     High 100%     High 100%
KGSP       High 100%     High  97%     High 100%     High 100%
KAVL       Med   67%     High  80%     High 100%     High 100%
KHKY       High  97%     High 100%     High 100%     High 100%
KGMU       High 100%     High 100%     High 100%     High 100%
KAND       High  82%     Med   79%     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:




  STATION      HIGH        LOW         HIGH        LOW
  -------  ----------  ----------  ----------  ----------
   KAVL      95 1983     69 1974     71 2015     50 1966
                1952        1938        1999
                1934                    1983
   KCLT     101 1987     73 1880     78 1991     56 2007
   KGSP     102 1952     74 1974     79 1934     59 1966


  STATION      HIGH        LOW         HIGH        LOW
  -------  ----------  ----------  ----------  ----------
   KAVL      96 1983     68 1985     71 1934     52 1966
   KCLT     100 1983     73 1938     78 2010     59 1947
                1952                    1883
   KGSP     101 1952     70 1985     79 2010     59 1904


  STATION      HIGH        LOW         HIGH        LOW
  -------  ----------  ----------  ----------  ----------
   KAVL      92 2010     68 2000     70 2012     51 1895
                2005                    2011
                1987                    2010
   KCLT     101 2010     69 2000     79 2010     62 1947
   KGSP     100 1995     72 2000     77 2010     57 1911




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