Area Forecast Discussion
Issued by NWS Greer, SC

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510
FXUS62 KGSP 301812
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
212 PM EDT MON MAY 30 2016

.SYNOPSIS...
The remnants of Bonnie will slowly lift northeast along the coast of
the Carolinas today through Wednesday. Moisture will increase ahead
of a cold front approaching from the northwest Thursday through
Friday. The front will move through the region on Saturday but
likely stall nearby over the weekend.

&&

.NEAR TERM /THROUGH TUESDAY/...
As of 130 PM: Cumulus have grown over the mountains in the past
90 minutes or so, and showers are now seen on radar over SW NC
and on the Blue Ridge north of I-40. This agrees with what the
HRRR et al. have been showing through the morning. Updated PoP and
Sky trends thru the aftn were based on a blend of this and other
hi-res models.

The remnants of former tropical cyclone Bonnie will remain
invof the "Grand Strand" into Tuesday morning, before beginning
a gradual northeastward movement by the end of the day. With the
low remaining on our periphery, northeasterly low level flow will
continue over our CWFA. This will provide enhanced moisture as well
as very weak convergence, which could allow some shower activity
to persist overnight. Plus, morning stratus is expected to develop
over the eastern third of the CWFA. However, the main driver for
precip during the period will remain diurnally driven instability.
Meso models (namely 4km NAM Nest and the NCEP HiRes WRFs) depict
most of the activity firing over the higher terrain Tue aftn,
though uncapped profiles are seen over the most of the Piedmont
as well. Hence a mentionable PoP extends throughout the area Tue,
with the best chances along the Blue Ridge once again.

With the western half of the CWFA expected to see only cirrus
overnight, and with winds remaining light, patchy fog is expected
to develop in some areas, though severe visibility restrictions
currently are not anticipated.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/...
At 300 AM EDT Monday: The remnant Bonnie circulation will lift
slowly northeast along the coast of the Carolinas Tuesday through
Wednesday. Warm and humid air will remain in its wake across the
western Carolinas and northeast Georgia. Scattered, mainly mountain
convection is indicated among the models for Tuesday and Wednesday
afternoon and evening. The light steering flow up the column will
create a heavy rain threat with any thunderstorms that form.
Instability appears much better on the NAM than the GFS given the
higher dewpoints, but moist vertical profiles should limit the
severe thunderstorm potential. Expect maxes to run about a category
above climo each afternoon, with mins two categories above climo
each night.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
As of 300 AM EDT Monday: Deeper layer southwesterly flow will
develop on Thursday as a northern CONUS low pressure system moves
into the western Great Lakes. Diurnal shower and thunderstorm
coverage will increase - especially over the mountains. The deeper
moisture will continue to pool ahead of an approaching cold front on
Friday with likely PoP to be advertised across the mountains and NC
foothills and solid chances southeast. Friday may be the warmest day
of the week with plenty of upper 60s lows and upper 80s highs.

The cold front will move through the region from the northwest on
Saturday but possibly stall just southeast of the region by late
day. Low levels never really dry out and another reinforcing cold
front will approach from the northwest on Sunday. In addition, upper
jet support may return along the southern Appalachians on Sunday as
height falls aloft carve out to the west. Chance PoPs for convection
will linger each day, but temperatures will gradually cool.

&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
At KCLT: Enhanced moisture and convergence on the western periphery
of former Tropical Storm Bonnie will maintain a moderately dense
Cu field over the area thru sunset. A chance of SHRA/TSRA exists,
but operational impact is too unlikely to warrant a mention. Winds
will remain generally NE, in fact mostly NNE this aftn. Moist flow
from the Coastal Plain is expected to bring in IFR stratus cigs
early Tue AM. This will take until late morning to dissipate,
likely being replaced quickly by low VFR Cu similar to how cigs
evolved Mon mrng.

Elsewhere: Primary impacts for the aftn will be from TSRA, which
will develop near the Blue Ridge and propagate S and SE. TEMPOs are
included to cover the threat, except at KAND where the chance is
lower. Chances for impactful precip diminish by sunset, though a few
showers may linger over the I-77 corridor and vicinity (including
KHKY) thru much of tonight. The low stratus that is expected
to creep into the NC Piedmont early Tue mrng is not expected to
bring a cig even as far west as KHKY, though some other parts of
the area (namely KAVL/KAND) will see patchy fog near dawn. Winds
will prevail NE, except NW at KAVL due to valley effects.

Outlook: Bonnie`s remnant low is expected to move very slowly
up the coastal Carolinas over the next several days, maintaining
increased precip and morning stratus chances at KCLT. Otherwise,
patchy fog chances continue at KAVL each morning, with scattered
afternoon/evening SHRA/TSRA increasing in coverage throughout
during the week.

Confidence Table...

            18-24Z        00-06Z        06-12Z        12-18Z
KCLT       High 100%     High 100%     High  90%     High  82%
KGSP       High 100%     High 100%     High 100%     High 100%
KAVL       High 100%     High 100%     High 100%     High  97%
KHKY       High 100%     High 100%     High  97%     High 100%
KGMU       High 100%     High 100%     High 100%     High 100%
KAND       High 100%     High 100%     High 100%     High  97%

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:

www.weather.gov/gsp/aviation

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...None.
SC...None.

&&

$$
SYNOPSIS...HG
NEAR TERM...Wimberley
SHORT TERM...HG
LONG TERM...HG
AVIATION...Wimberley



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