Area Forecast Discussion
Issued by NWS Greer, SC

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000
FXUS62 KGSP 241130
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
730 AM EDT SUN JUL 24 2016

.SYNOPSIS...
Broad high pressure will linger over the region through mid
week. During the late week, a mid level disturbance is expected to
slowly ripple over the forecast area. Moisture levels will gradually
increase across the western Carolinas and northeast Georgia by the
middle of the week as the region will remain on the warm side of a
stalled mid Atlantic front.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 650 AM, fog and patchy low stratus is gradually expanding
across the area this morning, so have made some adjustments to visby
and sky cover to account for this. Otherwise, as a trough in the
higher-latitude westerlies continues to pull away from the East
Coast today, upper heights will increase across the Southeast. In
fact, short term model guidance depicts a small upper level high
pressure center over western/ctrl NC this afternoon. Mid-
tropospheric temps are quite warm within this bubble, as high as -4C
at 500 hPa. Convective coverage Sat afternoon was a bit less than on
Fri (in most areas anyway) and today`s coverage should be a bit less
than on Sat in light of these warming mid-level temps/poor lapse
rates.

Today`s highest pops (generally 30-50) will again be reserved for
the high terrain. Mean cloud-bearing winds are expected to be out of
the E/NE, thus any convection developing over the mtns will be
carried away from the Piedmont, and pops drop off abruptly east of
the mtns accordingly. Having said that, quite a bit of convection
developed across the lower SC Piedmont and Midlands early Sat
afternoon, with attendant outflows pushing north and initiating
additional convection across the heart of the CWA throughout the
afternoon. There are some hints in the latest mesoscale/
convection-allowing guidance that this could happen again, albeit
perhaps on a smaller scale. Thus, slight chance pops will be carried
outside the mtns, mainly south of I-40. Sufficient buoyancy and
downdraft CAPE will yield a threat for a microburst or two.
Additionally, SW flow in the low levels turning to E/NE in the
mid/upper levels will yield very weak mean flow, so slow moving
cells producing heavy rainfall will also be a concern. Max temps are
expected to be a couple of degrees warmer than on Saturday in most
areas, and heat indices are expected to range in the 100-104 range,
mainly south of the I-85 corridor.

Convection should diminish quickly again this evening, giving way to
another unseasonably warm night.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
As of 230 AM Sunday: On Monday, H5 ridge centered over the western
Atlantic as a mid level disturbance tracks west across the northern
Gulf coast. Mostly clear morning sky conditions should result in
steady warming, expected to reach the lower 90s east of the mtns by
lunch. Temperatures are forecast to peak in the upper 80s within the
mtn valleys to mid 90s along and east of I-85. Steady SE winds
should keep dewpoints in the upper 60s to around 70 through the
afternoon hours. The combination of the hot temperatures and RH
around 50 percent should result in Heat Index values around 100
degrees east of the mtns. In addition, the hot and humid llvl
conditions has resulted in interesting forecast soundings Monday
afternoon. NAM soundings across the upstate of SC indicate CAPE
values between 2500-2700 J/kg, LFC a little less that 5 kft, little
to no late afternoon CIN, and around 2000 j/kg of DCAPE. I will
forecast TSRAs to develop over the mtn ridges during the mid
afternoon, then start to slide SE during the late afternoon to early
evening. Areas along and east of I-77 should see the least coverage.
Several of these storms will become quite tall, reaching to around
45 kft. Given the DCAPE and low shear, I would expect several
damaging wet microburst with pulse thunderstorms.

On Tuesday, the center of broad sfc high pressure will shift over AL
as a lee trough develops across the Piedmont. The sfc pattern will
result in light and steady downslope winds from the WSW. Forecast
highs may peak around degree warmer than forecast for Monday.
Dewpoints should range 2 to 3 degrees lower than values from Monday.
Forecast soundings indicate moderate instability with weak capping
east of the mtns. The forecast will continue to highlight high chc
to likely across the TN border counties, fading to chc against the
foothills. Foothill and Piedmont should verify well with schc pops
for SHRAs and TSRAs.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
As of 245 AM Sunday...A broad H5 ridge on Wednesday will give way to
a broad trough by Friday and Saturday. I will forecast diurnal chc
PoPs across the CWA on Wednesday. However, the arrival of the trough
would support greater coverage with less diurnal swings in coverage.
I will gradually increase PoPs to high chc to low likely by Sat,
keeping schc pops generally across the mtns during the overnight
hours. High temperatures are forecast to range for 3 to 4 degrees
above normal from Wednesday through the rest of the work week. On
Saturday, high temperatures are forecast to range 2 to 3 degrees
above normal.

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
At KCLT/KAND/KHKY, elevated dewpoints temps are resulting in
widespread MVFR, with pockets of IFR/LIFR conditions across the area
this morning. However, as of 1030Z, the above TAF sites were still
VFR, but will have to monitor trends closely over the next couple of
hours. Opted to included a tempo for 4SM at KHKY/KAND through 13Z,
but will leave it out of KCLT for now based upon a 4 degree
temp/dewpoint spread. Otherwise, with an upper ridge building over
the area and warming temps aloft, chances for convection appear to
be at their lowest in several days. Although isolated cells are
expected this afternoon, the coverage should be sparse enough to
preclude any convective mention attm. Winds are expected to remain
light S/SW through the period.

At KAVL/KGMU/KGSP, latest satellite imagery indicates KAVL is pretty
much surrounded by fog/low stratus this morning, and expect at least
brief LIFR conditions through 13Z. Meanwhile, an area of fog/low
stratus has wafted over KGMU from the southwest, and will also
include a tempo there through 13Z. It`s still uncertain as to
whether any of this will make its way to KGSP, but included a tempo
for 4SM/SCT004 there. Otherwise, isolated to scattered convection is
expected to develop once again Sunday afternoon, although coverage
may tend to be a bit less than in recent days. The best coverage
should be over the mtns, so a VCSH and PROB30 for TSRA is limited ti
KAVL for the time being. Fog will probably redevelop in the mtn
valleys tonight, although timing and the degree of restriction is
still highly uncertain. MVFR conditions should be good enough at
KAVL for the time being.

Outlook: Isolated to scattered afternoon/evening showers and
thunderstorms will continue across the mountains/piedmont through
mid-week, with coverage increasing Tuesday into Wednesday. 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...

            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       Med   61%     High 100%     High 100%     High 100%
KHKY       High 100%     High 100%     High 100%     High 100%
KGMU       High 100%     High 100%     High 100%     High 100%
KAND       High  94%     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:

www.weather.gov/gsp/aviation

&&

.CLIMATE...
ERATURE         MIN TEMPERATURE
  STATION      HIGH        LOW         HIGH        LOW
  -------  ----------  ----------  ----------  ----------
   KAVL      96 1983     68 1985     71 1934     52 1966
                                                    1895
   KCLT     100 1983     73 1938     78 2010     59 1947
                1952                    1883
   KGSP     101 1952     70 1985     79 2010     59 1904



RECORDS FOR 07-25

               MAX TEMPERATURE         MIN TEMPERATURE
  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
                            1890



RECORDS FOR 07-26

               MAX TEMPERATURE         MIN TEMPERATURE
  STATION      HIGH        LOW         HIGH        LOW
  -------  ----------  ----------  ----------  ----------
   KAVL      94 1949     72 1911     71 2012     49 1911
                1940                    2010
   KCLT     100 2005     74 1920     76 1992     60 1904
                1940                    1940
                1914                    1936
   KGSP      99 2010     76 1920     76 2005     53 1911
                1995                    1940
                1987



RECORDS FOR 07-27

               MAX TEMPERATURE         MIN TEMPERATURE
  STATION      HIGH        LOW         HIGH        LOW
  -------  ----------  ----------  ----------  ----------
   KAVL      97 1952     70 1946     72 1936     48 1911
                                        1925
   KCLT     103 1940     74 1926     76 1944     57 1920
                                        1940
                                        1936
   KGSP     103 1940     70 1946     75 2012     54 1911
                                        1944



RECORDS FOR 07-28

               MAX TEMPERATURE         MIN TEMPERATURE
  STATION      HIGH        LOW         HIGH        LOW
  -------  ----------  ----------  ----------  ----------
   KAVL      98 1952     68 1890     70 2010     53 1895
                                        1878
                                        1877
   KCLT     102 1952     70 1890     77 1997     54 1962
                                        1993
   KGSP     103 1952     72 1926     76 1936     60 1911
                                                    1904



RECORDS FOR 07-29

               MAX TEMPERATURE         MIN TEMPERATURE
  STATION      HIGH        LOW         HIGH        LOW
  -------  ----------  ----------  ----------  ----------
   KAVL      98 1952     67 1984     74 1877     55 1911
                                                    1895
   KCLT     103 1952     72 1984     77 1993     59 1920
   KGSP     104 1952     70 1984     76 1949     59 1911
                                        1936



RECORDS FOR 07-30

               MAX TEMPERATURE         MIN TEMPERATURE
  STATION      HIGH        LOW         HIGH        LOW
  -------  ----------  ----------  ----------  ----------
   KAVL      93 1954     68 1936     72 2011     54 2014
                                        1878        1897
                                                    1895
   KCLT     101 2011     71 1981     77 1953     58 1914
                                        1941
   KGSP     101 1999     73 1981     77 2011     60 1914
                                                    1911
                                                    1884

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...None.
SC...None.

&&

$$
SYNOPSIS...NED
NEAR TERM...JDL
SHORT TERM...NED
LONG TERM...NED
AVIATION...JDL
CLIMATE...GSP


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