Area Forecast Discussion
Issued by NWS Greer, SC
FXUS62 KGSP 230720
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
320 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.
.NEAR TERM /THROUGH TONIGHT/...
As of 310 AM, showers continue to dissipate as they move south
across the Upstate. The showers should diminish before daybreak. 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.
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
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.
.LONG TERM /THURSDAY THROUGH SUNDAY/...
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.
.AVIATION /08Z MONDAY THROUGH FRIDAY/...
At KCLT and elsewhere: showers moving south across the area will
move out before daybreak. Some BKN mid level clouds will linger
through daybreak as well. Northerly winds will generally be light,
but will briefly pick up near any showers. Expect high based cumulus
to redevelop with heating today, and could become BKN for the
afternoon. North to NE winds increase in speed with mixing today and
will become gusty at KAVL and possibly gusty at KCLT and KHKY.
Isolated showers are possible again, but chance too low to include
in for now. Winds and clouds will slowly diminish with sunset.
Outlook: Mainly VFR conditions will prevail through the week.
Scattered afternoon SHRA/TSRA may return Wednesday, with daily
coverage increasing Thursday and Friday.
07-13Z 13-19Z 19-01Z 01-06Z
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: