Area Forecast Discussion
Issued by NWS Greer, SC

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FXUS62 KGSP 271855

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
255 PM EDT Tue Jun 27 2017

A weak upper level system will cross the area by this evening,
but no precipitation is expected and dry and cooler weather
will continue through Wednesday. High pressure moves off the
East Coast on Thursday with warm and moist air moving north from
the Gulf through next weekend. This brings back the daily
chance of afternoon and evening showers and thunderstorms
through the weekend.


Visible imagery this afternoon showing diurnally induced fair
weather cumulus clouds across the area with thicker higher deck
of clouds over the northwestern half of the forecast area
associated with an approaching upper trough axis. Atmospheric
moisture is quite limited with precipitable water values ranging
from around 0.8 inches in the NC mtns to around an inch in the
Piedmont which is limiting instability and ultimately
precipitation associated with the trough.

Surface high pressure centered over the western Ohio Valley will
continue to build southeastward tonight and settle over the
region. Diurnal clouds should dissipate with sunset and the
higher clouds will shift east this evening resulting in good
radiational cooling overnight. The cool and drier airmass will
support low temperatures well below normal in the mtns and below
normal in the Piedmont with lows generally ranging from the
lower 50s in the higher terrain to the lower 60s in the
southeastern counties.


Wednesday, cool high pressure will be centered over the
Appalachians, leading to another day of below- normal
temperatures. The high will move offshore late in the day, with
moist return flow ensuing.

Thursday, a shortwave and increasing Gulf Coast moisture will move
in to the region. Weak isentropic upslope flow will bring a return
of diurnally-driven thunderstorms to the mountains and portions of
the Upper Savannah Valley on Thursday. While temperatures will
remain below seasonal normals, the increase in low level moisture
will bring humidity levels up with a return to more muggy
conditions. This Gulf moisture advection will continue to propagate
east and toward the Carolinas as the surface high pushes farther off
the coast. By Thursday night, should see lows pretty much near
seasonal normals with dewpoints continuing to rise.


Warm moist advection will continue through Saturday, allowing for
mainly diurnal convection.  A weak front will stall near the area
this weekend, with another enhancement to diurnal pops on Sunday.
The front may push south of the area by Monday as an upper ridge
builds into the Lower Mississippi Valley. Expect near normal
temperatures and a continued enhancement in diurnal pops through the
end of the period.


VFR conditions are expected through the 18z TAF period. An upper
trough will cross the area this evening while surface high
pressure will build into the region from the northwest
overnight. Atmospheric moisture is very limited with no
precipitation expected. Northeasterly winds 5 to 10 knots
expected through the early evening then becoming light
northeasterly to near calm overnight.

Outlook: light winds and VFR conditions should continue through
mid week. Moist, southerly return flow will develop around the
offshore ridge on Thursday. As a result, typical summertime
conditions will return by the end of the work week, with mainly
late afternoon/ evening SHRA/TSRA causing possible restrictions.

Confidence Table...

            15-21Z        21-03Z        03-09Z        09-12Z
KCLT       High 100%     High 100%     High 100%     High 100%
KGSP       High 100%     High 100%     High 100%     High 100%
KAVL       High 100%     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 100%     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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