Area Forecast Discussion
Issued by NWS Greer, SC

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FXUS62 KGSP 231447

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1047 AM EDT MON MAY 23 2016

Dry high pressure builds into our region from the Mississippi
and Ohio valleys for the first half of the week as low pressure
lingers over the Mid-Atlantic. A moist southerly flow develops in
the middle of the week, which will lead to warmer temperatures
and mainly afternoon chances of showers and thunderstorms each
day into the weekend.


As of 1045 AM EDT:  Fairly nice morning underway across the region
as earlier mountain valley fog has eroded yielding sunny skies,
with llv cu starting to develop along the higher ridgetops.  Cu is
also starting to blossom along the I40/I77 corridors across western
NC where lapse rates have improved with heating.  As for the fcst,
did lower pops a bit to comply with latest nam, however still
think low end slight chances are warranted along north of I40 this
afternoon, as well as over the central/northern mountains where
mid level temps are a bit cooler allowing for steeper lapse rates
and thus slightly enhanced cape.  Otherwise, tweaked t/td in the
immediate near term and left the remainder of the fcst as it was.

The center of the coastal H5 closed low will drift over the western
Atlantic, but leave cyclonic flow across the Atlantic states. The
circulation around the low should result in cloud cover returning to
the I-40 and I-77 corridors today. Mid level temps will remain quite
cold due to the flow around the low. This will result in just enough
instability for isolated showers to redevelop during the afternoon
across the northern tier of the CWFA. Some mid level clouds will
develop across the rest of the area today, but no showers. There
will be some gusts again across the mountains today, but lighter
winds elsewhere. Highs will be around 5 degrees below normal.

Although clouds will linger across the area this evening, any
showers will dissipate quickly with loss of heating. Light winds
and clearing skies will compete with an increasingly moist air
mass leading to lows a couple of degrees below normal.


As of 300 AM Monday: Closed upper low over the Mid-Atlantic will move
east and begin to fill Tue into Wed. A broad upper ridge will shift
into the Southeast in its wake over this period. Low level flow will
remain westerly, tempering moisture return. A midlevel subsidence
inversion will cap convection Tuesday, and while this is still seen
Wed, temperatures will have trended upward enough that models do
generate a small amount of convection over the mountains. Temps will
be near normal Tue and Tue night, and about a category above normal
Wed and Wed night.


As of 245 AM Monday: For the late week and weekend the Bermuda
High will be in full control of the pattern over the Southeast, that
is, temperatures will be seasonably warm and precip chances resulting
from diurnal convection. CAPE values trend upward Thu to Fri as the
airmass modifies and warms, so a slight uptick in PoPs is included to
match. With essentially no shear, the usual pulse storm threats can
be expected: locally heavy rain, brief hail, and perhaps strong
downbursts. Upper heights continue to rise into the weekend, and GFS
expects subsidence will cap most convection Sat-Sun, though the EC
allows CAPE to continue to trend upward. Models resolve a bit more
cloud cover those days and temps accordingly are a couple degrees
cooler. Highs Thu-Fri look to be near 5 degrees above climo, dropping
back to a degree or two above climo over the weekend. Latest GFS does
depict a tropical system approaching the GA/SC coasts early Monday,
but run-to-run consistency with this feature has been very poor, and
is not yet depicted on other major models, so confidence is much too
low to mention in the official fcst.


At KCLT and elsewhere: dense fog at KAVL should dissipate quickly
this morning. Otherwise...high based stratocumulus will spread in
from the north through the day with some ceilings possible for the
NC sites. Cannot rule out a shower for the afternoon at KHKY, but
chance too low to include. N to NE wind will continue through the
day with low end gusts at KAVL. Clouds dissipate and winds become
light SE or calm through the evening. Fog will be possible again at
KAVL Tuesday morning.

Outlook: Mainly VFR conditions will prevail through the week, but
patchy morning fog chance continues at KAVL. Scattered afternoon
SHRA/TSRA may return Wednesday, with daily coverage increasing
Thursday and Friday.

Confidence Table...

            14-20Z        20-02Z        02-08Z        08-12Z
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  85%
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:




SHORT TERM...Wimberley
LONG TERM...Wimberley
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