Area Forecast Discussion
Issued by NWS Greer, SC

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FXUS62 KGSP 221820

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
220 PM EDT SUN MAY 22 2016

Dry high pressure builds into our region from the Mississippi
and Ohio valleys early this week as low pressure lingers over
the Mid-Atlantic. A moist southerly flow develops by mid week and
continues into the weekend.


As of 210 pm, the pressure gradient will relax from 4 mbs this
afternoon to 2 mbs around 0z. The weakening gradient and decreasing
mixed layer will bring an end to gusty NNW winds. The center of a H5
closed low should continue to drift south across the mid Atlantic
states through this evening and into the late night hours. As the
mid level low approaches, CAMs indicate a small increase in coverage
of weak showers across the nrn NC mtns, foothills, and Piedmont
through 3z. I will highlight the weak showers with schc PoPs.
Otherwise, the sensible weather tonight should feature partly cloudy
sky cover and light NW winds. Lows are forecast to range in the
upper 40s across the mtns to mid 50s across NE GA and the upstate.

Monday, the center of H5 closed low will drift over the western
Atlantic, but leaving cyclonic flow across the Atlantic states. The
circulation around the low should result in greater cloud cover
north of I-40, with the rest the CWA under mostly to partly sunny
conditions. Winds will be much lighter than Sunday, remaining from
the north through early afternoon before varying. High temperatures
are forecast to range only a degree or two warmer than Sunday highs.


As of 155 PM Sunday...the early to middle part of the week will see
a slow transition in the upper pattern. The old upper low off the
Mid-Atlantic coast at 00Z Tuesday will move to the New England coast
Monday night and Tuesday allowing a flattening upper ridge to build
in from the west through Tuesday night. No changes to earlier
thinking that surface high pressure will control our weather, which
will be dry with a warming trend back to just above normal Tuesday
and then warming to something on the order of five degrees or so
above normal on Wednesday. If there is an issue, it will be the
chance and extent of convective precip Wednesday afternoon. The
model guidance suggests the better low level moisture will remain
well to our west through the end of the day, so not much coverage is
expected. Cannot rule out a few showers developing over the higher
terrain late in the day, especially the Smokies, so a small PoP will
be carried there.


As of 215 PM Sunday, The forecast models are similar in showing the
upper pattern amplifying late in the week with a trough digging over
the Rockies and plains and ridge building over the east.  At the
surface, high pressure will anchor over the mid-Atlantic near or
over VA as waves of low pressure move NE from the plains to the
Great Lakes with fronts nearly stationary in an arch.  Some energy
and instability affecting the western Carolinas and NE GA as we
remain in the warm sector for several days. Low level wind flow will
be S to SW Friday into Saturday becoming lighter and more variable
late in the weekend.  Instability each afternoon generally along the
values of 1000 to 1500 CAPE mainly over the NC mtns. Wind shear
light.  At the end of this period, the models have the East Ridge
breaking down early next week with GFS showing a tropical low
forming east of FL to start the week then drifting north over the
Carolinas toward mid week. We have days to watch this to see if
other models come onboard.

Max temps mostly in the 80s for lower elevations and Mins in the
60s into weekend then slightly cooler as ridge breaks down.


At KCLT and elsewhere...VFR. The center of a mid level low will
continue to drift southward through the evening hours. During the
remainder of the daylight hours...gusty NNW will remain across the
western Carolina terminals. Moisture and weak forcing associated
with the low may support a few weak showers...passing near KHKY and
KCLT through 23z. Wind gusts and showers should dissipate during the
early evening hours. On Monday...weak pressure fields will support
only light north winds. Conditions across the terminals should
remain dry.

Outlook: Mainly VFR conditions will prevail through the early
week. Scattered afternoon SHRA/TSRA may return Wednesday, with
daily coverage increasing Thursday and Friday.

Confidence Table...

            18-24Z        00-06Z        06-12Z        12-18Z
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 schedule 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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