Area Forecast Discussion
Issued by NWS Greer, SC

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FXUS62 KGSP 161512

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1112 AM EDT Sun Jul 16 2017

A cold front will stall near the area today, while another front is
expected to approach on Monday. A strong upper ridge will build
into the area during mid-to-late week, bringing a return of hot
temperatures and reducing the coverage of afternoon and evening
showers and thunderstorms.


As of 1030 AM EDT Sunday: Have adjusted pops through the day, mainly
to lower them this morning before onset of convection and reduce
them across the northern tier. Dewpoints also seem to be running a
little below forecast so have adjusted those as well. Otherwise, we
will remain under the influence of the persistent upper trof to our
north and broad upper ridging to our west. At the sfc, a stalled
cold front will linger just to our south today and tonight as high
pressure tries to push farther into the fcst area from the north.
The latest model guidance has been trending drier over our northern
zones for today and tonight with the deeper moisture getting pushed
to the roughly southern half of the CWFA. This trend has also been
reflected in the CAMs, which now depict more isolated convective
development over most of Western NC. As such, I trended PoPs down a
bit over those zones but kept high-end solid chances for the SC and
GA zones. Severe convection will be less likely today compared to
the past couple of days, however a few isolated svr cells cannot be
ruled out, especially over the southernmost zones.
Temps should be a few degrees cooler today with highs near normal
if not slightly below, and lows overnight right around normal.


of 315 am Sunday: Upper trough will gradually shunt east and
weaken during the short term, as expansive upper high/ridge begins
nosing into the region from the central Conus by the end of the
period. This will result in a return to normal temps by Tuesday.
Afternoon buoyancy will remain typically moderate/strong through the
period, with scattered/near climo coverage of deep convection
expected both Monday and Tuesday afternoons. The convective threats
will be standard mid-summer fare: slow-moving cells causing locally
heavy rainfall and isolated pulse severe storms yielding primarily a
microburst threat.


As of 320 am Sunday: The medium range will see the aforementioned
upper ridge asserting its dominance over Southeast weather. The main
result will be a return to above-climo temps that are expected to
persist through the period, with mid-90s likely across much of the
Piedmont and foothills by late-week. The increasing subsidence will
tend to discourage convective initiation/limit buoyancy, and daily
coverage of diurnal convection should remain widely scattered/
isolated at best through the end of the work week. There are
indications that the ridge could become suppressed to our south by
Day 7, so pops return to around or above climo levels next


At KCLT and Elsewhere: Have removed TEMPO and PROB30 TSRA for
the KCLT 15z AMD as new guidance indicates convection chances too
low for these, but have replaced with VCSH. Otherwise, expect mostly
VFR conditions thru 12z taf period. The stalled front will remain
nearly stationary over our southern fringe today/tonight with
guidance expecting enough instability for another round of
convection this afternoon/evening. The guidance has been trending
drier for the NC zones today/tonight, so I removed the PROB30 groups
from KAVL and KHKY and just kept a VCTS for those sites thru roughly
00z Monday. Winds will be light favoring a NLY direction early on,
then switching back to S to SWLY by the early afternoon.

Outlook: Scattered to numerous afternoon and evening thunderstorms
are expected both today and Tuesday across the area, with better
coverage over the mountains for Tuesday. Morning fog development
can be expected in the mountain valleys and in areas that receive
rainfall the previous afternoon/evening. Drier air will likely
limit convective coverage for Wednesday and Thursday.

Confidence Table...

            15-21Z        21-03Z        03-09Z        09-12Z
KCLT       High 100%     High 100%     High 100%     Med   71%
KGSP       High 100%     High 100%     High 100%     High  85%
KAVL       High  98%     High 100%     High 100%     High  84%
KHKY       High 100%     High 100%     High 100%     Med   77%
KGMU       High 100%     High 100%     High 100%     Med   79%
KAND       High 100%     High 100%     High 100%     Med   63%

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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