Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Greenville-Spartanburg SC
221 PM EDT Sat Oct 25 2014
high pressure will give way to a progressively warmer southwest flow
of air before a cold front crosses the region on Wednesday. Steadily
cooler temperatures will be then seen during the latter half of next
Near term /through Sunday/...
as of 200 PM EDT Saturday...the upper pattern continues to be
highlighted by large 590mb 500 mb ridge centered over the Southern
Plains while a closed 500 mb low pushes through southern Ontario. At
the surface...high pressure prevails across the southern/central
Apps while a weak and rather dry cold front extends along a surface
trough through the middle Mississippi and western Ohio valleys. As said
above...models dont indicate much moisture associated with the front
therefore not expecting much impact on the sensible weather as it
slides through overnight. That said...low level relative humidity fields are
elevated to the Point of warranting a few hours of isolate probability of precipitation
along the Tennessee border amongst the northern NC mnts where weak upslope
shower potential cant be overlooked. Due to southwesterly backed
warm air advection flow this afternoon along with abundant radiational
warming...not expecting any frost/freeze concerns Sunday morning as
min temperatures are forecast to hold in the upper 40s to lower 50s outside of
the mountains where 40s will prevail. Sunday will feature drier
northerly flow ahead of a reinforcing back door front late in the
day associated with high pressure diving through the Ohio Valley.
Heights are expected to rise aloft leading to a dry forecast with
mostly sunny skies prevailing. Temperatures on Sunday will actually
be slightly warmer than that of today with highs forecast to exceed
normal levels due to building upper ridge and abundant heating.
Short term /Sunday night through Tuesday/...
as of 155 PM Sat...upper ridge axis moves across the area Monday and
off shore Tuesday. At the surface...a weak frontal system over the area
moves back north as a warm front Sun night with southerly flow developing
Monday as high pressure moves off shore. A cold front moves into the Tennessee
Valley late Tuesday...but the forecast remains dry as any precipitation is well to
our west. However...there will be a slow increase in clouds. Lows
near normal Sun night rise well above normal Monday night...while highs
remain nearly steady well above normal each day.
Long term /Tuesday night through Saturday/...
as of 100 PM Sat...the 25/12 UTC op GFS supportive of wpc extended
forecast forecasts in the handling of progressive and weakening cold frontal
zone across the County warning forecast area Wednesday into Wednesday night leading to the chance for
a round of showers for most places. Medium range model consensus has
been trending more agressive with respect to the influx of drier and
less warm air for Thursday. For the latter half of the period...
expecting pronounced eastern Continental U.S. L/WV trough to develop and
progessively cooler air to overspread the region.
Aviation /19z Saturday through Thursday/...
at kclt and elsewhere...VFR conditions will prevail at all sites
through the taf cycle. Weak cold front approaching from the west
will pool low level moisture against the western slopes of the high
terrain leading to low VFR ceilings at kavl by middle/late evening.
Otherwise...skies will remain mostly clear with the exception of a
few middle/high level cirrus streaming through. Heights will rise
behind the front leading to continued clear/sunny skies Sunday
morning through the period. Winds will back to the southwest ahead
of the weak frontal passage this afternoon at all sites before increasing and
veering back to the northwest behind the boundary overnight. By
morning winds remain elevated and out of northwest through the
remainder of the taf cycle.
Outlook...aside for a brief/weak cold frontal intrusion Saturday
night leading to broken low VFR ceilings across the mountains...deep layer
ridging will dominate the pattern through the first part of the work
week leading to quiet weather and a low probability of flight