Area Forecast Discussion
Issued by NWS Greer, SC
FXUS62 KGSP 272341
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
741 PM EDT FRI MAY 27 2016
After a dry day on Saturday, a period of cooler and wetter weather
may develop late in the weekend through early next week as Atlantic
low pressure moves toward the South Carolina coast.
.NEAR TERM /THROUGH SATURDAY/...
As of 7:30 pm EDT Friday...convective showers have drifted NE out of
the NC mountains and into northeast TN and southwest VA. Expect the
rest of the evening and overnight to be quiet.
Otherwise...southerly low-level flow is weak and does not maintain
boundary layer moisture on Saturday, with dewpoints actually
dropping a couple degrees. Consequently the weak convection seen
this past afternoon is less likely Saturday, with convective instability
Synoptically, area is on the west side of a broad upper and lower
ridge over the Atlantic as a stronger trough over the central CONUS
makes gradual eastward progress. Tropical low continues to organize
northeast of Florida and will begin to affect coastal areas on
Saturday. With slow progression of synoptic pattern, main change
for Saturday will be a little warmer temperatures and dryer boundary
layer with few, if any showers over the mountains.
.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
At 230 PM Friday, on Saturday evening an upper ridge will extend
from the atlantic ocean to the mid atlantic states, while an upper
trough will be over the eastern plains, and an upper low will be
near the southern SC coast. The models move this upper low slowly
inland over SC on Sunday, while the upper trough progresses to the
wester Great Lakes, and the upper ridge progresses over New England.
By Monday the low weakens near the SC and NC border, while the
upper trough deamplifies over the easter Great Lakes, and the ridge
downstream reaches the eastern Canada.
At the surface, on Saturday evening the models show a surface low
ostensibly associated with tropical development approaching the SC
coast approaching, with associated moisture moving inland over the
Carolinas. The models differ on the movement of the low into Sunday,
and therefore the amount of moisture reaching the western Carolinas
and northeast Georgia. At this point the bulk of precipitation is
expected to be near the SC coast, but uncertainty remains on inland
amounts. Model soundings vary on the amount of instability over our
area on Sunday and Monday, depending on how moist the atmosphere
becomes. Temperatures should exhibit a reduced diurnal range if
moisture can indeed spread inland over our area.
.LONG TERM /MONDAY THROUGH FRIDAY/...
At 230 PM Friday, on Monday evening, an upper low will be weakening
near the SC and NC border. The models have disagreed on the precise
location of a an associated surface low over either SC or NC, but
now appear to move this system off the southern NC coast on Tuesday,
where it dissipated on Thursday.
By Friday an upper ridge progressing to the east coast deamplifies,
while a cold front approaches from the northwest, preceded by
sufficient moisture to support widespread precipitation.
Precipitation amounts are currently forecast to be rather limited
west of the coastal Carolinas, however if the surface low can reach
far enough inland, and linger there, rainfall totals could be
Temperatures may exhibit a reduced diurnal range if moisture lingers
over the area, otherwise they would run near normal under nearly
zonal upper level flow.
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
At KCLT and elsewhere east of the Blue Ridge...VFR through the
period. Few stratocu should diminish with sunset. Expect a light SE
or light/variable wind overnight. On Saturday...wind should come
back up from the ESE as a low of tropical origin approaches the SC
coast. The low may spread some mid-level clouds in from the east in
the afternoon...while high based stratocu develop again.
At KAVL...there is some concern for fog in the pre-dawn
hours...perhaps likely now that a shower occurred this past
afternoon. The fog may briefly reach IFR around daybreak. The fog
should dissipate by mid morning.
Outlook: Mainly VFR conditions will prevail through the period, but
patchy morning fog chances continue at KAVL. Scattered afternoon
SHRA/TSRA coverage will return on Sunday, with increasing chances
into early next week.
23-05Z 05-11Z 11-17Z 17-18Z
KCLT High 100% High 100% High 100% High 100%
KGSP High 100% High 100% High 100% High 100%
KAVL High 100% High 100% Med 61% 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: