Area Forecast Discussion
Issued by NWS Greer, SC
FXUS62 KGSP 240542
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
142 AM EDT TUE MAY 24 2016
Dry high pressure will build 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 by
the middle of the week, which will lead to warmer temperatures
and mainly afternoon chances of showers and thunderstorms each
day into the weekend.
.NEAR TERM /THROUGH TODAY/...
At 140 AM, lingering mid clouds under a subsidence inversion will
slowly dissipate through daybreak. Patchy fog expected again by
daybreak, with patchy dense fog possible in the mountain valleys.
Temps are trending colder where clouds are minimal, so have adjusted
lows downward in those areas.
For Tuesday, the fcst remains dry with a few cu possible, however
with less overall density as soundings exhibit a dryer llv layer
than that of today. Likewise, mid level temperatures will be warmer
amidst rising heights as the upper ridge settles in.
Temperatures through the period will warm with overnight lows near
normal, leading into afternoon highs topping out a few degrees above
normal for Tuesday.
.SHORT TERM /TONIGHT THROUGH THURSDAY/...
As of 130 PM Monday...The upper pattern will dominate the sensible
wx through the short-term period as deep layered ridging slowly
crosses east. Soundings indicate a strong subs inver developing
Wed...which will effectively limit the convec potential to the nc
mtns as llvl moist flux remains weak. Will continue the isol pop
mention late Wed across the mtns with fair wx cu and ci anticipated
across the non/mtns. The Atl ridge backs off slightly Thu and this
will allow a bit better moisture transport as llvl winds align more
sw/ly. With max temps remaining above normal...the increase in Td/s
shud enable at least moderate levels of SBCAPE based on a GFS/NAM
blend. Pops are more expansive Thu...but will mainly cover the mtns
and nc fhills. The flow through the column remains very weak...thus
storms that develop will be thermally cyclic and unorganized. The
main stg/svr threat from the deeper tstms will be large hail with a
couple lower-end microbursts possible.
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
As of 2 PM Monday, Upper heights rise into the weekend as the ridge
builds over the East and broad trofiness lingers over the Western
half of the nation. Meanwhile, a wave of low pressure initially
over the Bahamas Thursday night and Friday will drift north toward
SC through the weekend. This feature was originally displayed just
on GFS but now other models are showing it as well with some timing
differences. However, the GFS solution for development is considered
a low possibility. The inverted wave should remain weak as it drifts
toward the SC coast.
Waves of low pressure will track from near TX to the Great Lakes
then east over the top of the ridge. High CAPEs and other factors in
organized SVR threats will stay out over the plains and Miss Valley
areas. Models have generally low CAPE over the western Carolinas and
NE GA Friday PM...only 500 or less on GFS for NC mtns. A little
better instability on Saturday although the GFS has the tropical
low east of Savannah at 00Z Sunday. For Sunday and Monday, the GFS
and ECMWF have differences based on the advancement of the tropical
low across the mid Atlantic on the GFS as it has the low crossing
central NC at 18Z Monday. The ECMWF has a tropical low reaching the
GA coast at 12Z Wed which is after our current forecast period.
Our low level wind flow is forecast to be from a general southerly
direction Friday and Saturday, light and variable Sunday then based
on ECMWF will be from the east early next week.
Max Temps well into the 80s Friday and Saturday then cooling to 70s
mtns and lower to mid 80s Piedmont by Monday. Min Temps in the 60s.
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
At KCLT and elsewhere: A BKN area of mid clouds trapped under a
subsidence inversion will slowly dissipate by daybreak, with FEW to
SCT clouds elsewhere. Although patchy fog develops again by
daybreak, KAVL looks to be the only TAF site with restrictions.
Could be VLIFR once again. Expect little in the way of clouds today,
but some afternoon ridge top CU should develop. Mid and high clouds
return from the west tonight. Light and variable to calm winds this
morning will become S to SW by afternoon. Winds become light or calm
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.
05-11Z 11-17Z 17-23Z 23-00Z
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 schedule TAF issuance flight rule category. Complete hourly
experimental aviation forecast consistency tables and ensemble forecasts
are available at the following link: