Area Forecast Discussion
Issued by NWS Greer, SC

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FXUS62 KGSP 140239

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
939 PM EST Mon Feb 13 2017

Temperatures will hover just above average early in the week as a
high pressure system settles over the southeast. A stronger cold
front will cross our region Wednesday, bringing light precipitation
and dropping temperatures to near normal levels Thursday. A rapid
warming trend will commence heading into next weekend.


As of 935 PM EST: Observed temperatures continue to run a touch
above the forecast temperature trends, but the cirrus has largely
thinned this evening and winds are becoming lighter with time. Still
anticipate mins reaching the currently forecast min values despite
some cirrus returning from the west overnight.

Otherwise, very quiet weather will continue through the near-term
with weak ridging aloft and surface high pressure building over the
area. A split-flow pattern arising from the deep upper low off New
England plus a cutoff over the Desert Southwest will slide east
through the period - lifting the southwest cutoff into the Southern
Plains. But for us, the weather will be fairly benign with weak
shortwaves embedded in the flow aloft bringing just some
intermittent high cloudiness across the area.

The surface high will slide southeast tomorrow and WAA will pick up
again with highs tomorrow similar to those today. However, moisture
associated with a warm front lifting north from the surface low
associated with the southwest cutoff will begin approaching the
Southern Appalachians toward the end of the period. An increase in
high and then mid-level clouds is expected, which will keep
temperatures from increasing even more. At the very end of the
period, we may see some light rain showers begin to move into the
mountains, but the bigger impacts will hold off until the short term.


As of 200 PM Mon: An initially closed upper low over the ArkLaTex
region Tuesday evening will phase with a northern stream wave
and swing into the Southeast early Wednesday. This feature will
be associated with a weak surface low; a warm front will set up
overhead Tuesday and bring increasing clouds and precip chances
that night, with peak chances Wed morning as the low scoots by
to our south. A blend of WPC and global model QPF falls near the
middle of the SREF and GEFS plumes, which looks appropriate at
this point and is therefore reflected in the fcst.

The track of the low and partial thicknesses suggest the mountains
and perhaps even NW NC Piedmont will be marginally cold enough to
support mixed ptypes Tue night into early Wed. Indeed, surface temps
will be near or slightly below freezing at higher elevations, but
guidance suggests the valleys and foothills will be too warm. Deep
saturation is present at the height of the event and ice nuclei
are likely to be available; cold advection in the wake of the
low is progged to cool the column uniformly and it appears safe
to advertise only rain and/or snow. The highest elevations may
see as much as 3 inches, but populated areas are not expected to
see more than 2. Northwest flow continues into early Thursday but
moisture currently looks to be too paltry for accumulating snowfall
to continue past late afternoon Wed.

Dry and mostly clear conditions are expected Thursday as high
pressure builds in. Expect gusty northwest winds over the mountains,
though perhaps not as much as what has been experienced in the
past couple of cold-advection events there (i.e., below advisory
criteria). Max temps will be a shade below normal.


As of 200 PM EST Monday...A broad sfc high will slowly cross the
area Fri and Sat maintaining mostly dry conds with temps increasing
to arnd 10 degrees above normal each day. An upper level ridge will
give way to an income cut-off low during the day Sat. The sfc
reflection with this upper low will be rather weak and held south of
the FA. The models have been consistent with keeping the best llvl
forcing and moisture south...however the Carolinas and NE GA will
come under the influence of strong ulvl difl flow and increasing
h7-h5 DPVA. This forcing will help generate some -shra across the
area Sat afternoon...however with a stable column in place...deep
convection shud not be an issue. Basically a quick and low-end qpf
scenario is in store. Upper ridging builds back in Sun and crosses
east thru Mon. This will return dry conds and max temps shud reach
about 15 degrees abv normal in persistent deep layered subs. Another
more dynamical forced frontal system is on the horizon for Tue
according to the ECMF/CMC models...however very little support is
given by the GFS. This situation will be one to keep an eye next
week as the overall pattern suggests the likelihood for a
destabilizing atmos and increasing shear.


At KCLT and Elsewhere: VFR conditions will continue through the
period, with intermittent high and mid-level clouds and some
lowering VFR late Tuesday. Winds should go light overnight and turn
around the dial through a northeasterly direction and then SE by
Tuesday morning. Anticipate winds coming up from the S to SW with
mixing through the day on Tuesday.

Outlook: A low pressure system organizing across the Southern Plains
may bring moisture and associated restrictions back into the area
Tuesday night through Wednesday. Conditions dry out again for later
in the week.

Confidence Table...

            02-08Z        08-14Z        14-20Z        20-00Z
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:


Fuel moistures are expected to become marginally critical again
tomorrow, but RH values are not expected to be as low as low-level
flow turns southwesterly out of the Gulf.




SHORT TERM...Wimberley
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