Area Forecast Discussion


350 
FXUS62 KGSP 141956
AFDGSP
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
256 PM EST Fri Dec 14 2018
.SYNOPSIS...
Low pressure will move across the region later tonight and tomorrow 
bringing widespread precipitation to the area. Broad high pressure 
is then expected to spread over the region and provide warmer and 
drier conditions for early next week.
&&
.NEAR TERM /THROUGH SATURDAY/...
As of 250 PM EST Friday: A Flood Watch remains in effect for 
portions of western NC through Saturday evening. 
With plenty of cloud cover in place and isolated to scattered 
showers (heavy at times) today pushing from SW to NE across the 
area, it's been quite the dreary Friday, as the insitu wedge in 
place across most of the FA has allowed for temperatures to only 
climb into the 40s this afternoon. With the combination of a low 
pressure system slightly less organized than previously expected 
(currently located over LA/MS/AR) and the infiltration of some drier 
air, rainfall amounts have not been as high as previously 
anticipated. Though the area is in somewhat of a precip lull attm, 
with latest radar imagery depicting the western Carolinas and 
northeast GA surrounding by rainfall to the west, south and east, do 
anticipate an uptick in precipitation across the area tonight 
(supported by latest CAM guidance), as sfc low pressure gradually 
pushes northeastward. Attm, with anticipation of additional 
precipitation and snow melt, the Flood Watch remains in effect through 
Saturday evening. Given a non-diurnal temperature trend today, 
expect temperatures overnight to remain relatively the same from 
today.
On Saturday, sfc low pressure will continue to push northeastward, 
though stay just to the west of the TN/NC border, through Saturday 
afternoon, as it's associated warm front/cold front near the area. 
Scattered showers will continue through the morning hours, gradually 
tapering off into the late afternoon/early evening from SW to NE. 
With the insitu wedge retreating, do expect high temperatures to be 
slightly warmer on Saturday than today, into the low to mid 50s, 
into the upper 50s to the SE and into the upper 40s across the 
higher elevations.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
As of 110 PM EST Friday: A good amt of h92-h85 moisture will be 
associated with an occluded sfc low as it traverses toward the OH 
Valley Sun. With good mech/dyno lift...the NC zones will likely see 
low-end -shra overnight with some -snsh across the highest peaks. No 
sigfnt snow accum is expected into Sun night before the main system 
pushes further north and dry air works in from the southwest. 
Rainfall totals thru the day Sun will also be low with less than a 
quarter inch anticipated and mainly across the nrn NC mtns. Winds 
will align nw/ly to w/ly thru the period as the p/grad aligns 
parallel to the mtn chain. This will produce a relative warming 
downslope component...and along with increasing insol...max temps 
will rebound to arnd normal levels Sun. On Mon...llvl thicknesses 
support max temps in the m60s over the non/mtns. Wont go that high 
yet...but will mention l60s. Either way...Mon will be a rather nice 
day after all the clouds and precip recently. Mins will be held 
right arnd normal thru the period.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
As of 220 PM EST Friday: A pretty uneventful couple days to begin 
the long term period. A sw/nw elongated upper ridge will slowly 
cross the eastern CONUS and support broad high pressure at the sfc. 
This stacked high will support a dry column with PWATS generally 
remaining below 0.5 inches....or arnd normal for this time of year. 
Winds within the mixed layer will be weak...which will lead to a 
couple nice seasonal days outside of increasing Ci on Wed. 
On Thu...things begin to change. That/s about all that can be said 
for now as the models have varying ideas with the structure of an 
incoming h5 trof and the degree of available moisture advection. 
Climatologically with an upper trof approaching this time of 
year...there shud be a defined llvl pressure response and likely 
good moist flux out of the GOM/Atl. However...the GFS is an 
oddball soln with a cutoff GOM feed and a limited qpf response 
mainly across the wrn NC mtns. Other guidance shows better 
moisture and precip reaching the FA Thu into Fri. In all cases 
tho...the overall pattern would support all rain outside of some
diurnal high mtn -snsh each night. So with the uncertainty 
had...will keep slight to low-end chance PoPs during the latter 
period. Max temps are still progged to reach arnd normal levels 
Thu/Fri as the llvl flow remains w/ly to sw/ly.
&&
.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
At KCLT and elsewhere: Expect mixture of IFR/LIFR to persist through 
the rest of today and through the overnight hours with the continued 
infiltration of moisture, low cigs, areas of fog, periods of 
isolated to scattered showers and the insitu wedge in place. 
Conditions will gradually improve to MVFR throughout the day on 
Saturday as low pressure system pushes into the Mid Atlantic and 
precipitation tapers off from SW to NE. With insitu wedge in place, 
northeasterly winds around 10 kts, with occasional higher gusts, 
will prevail at all sites with the exception of KAVL (SE winds 5 to 
7 kts). Winds on Saturday will gradually veer to the SE as the wedge 
in place retreats. 
Outlook: Expect VFR through into the middle of next week as drier 
conditions return, with the exception of areas of upslope-driven 
cloud cover along the Tennessee border on Sunday.
Confidence Table...
            20-02Z        02-08Z        08-14Z        14-18Z 
KCLT       High  94%     High  80%     High  88%     High  92%     
KGSP       High  93%     High  90%     High  90%     Med   74%     
KAVL       High  93%     High  89%     Med   78%     High  96%     
KHKY       High  93%     High  94%     High  92%     High  86%     
KGMU       High  93%     High  90%     High  90%     Med   77%     
KAND       High  94%     High  93%     Med   79%     High  86%     
The percentage reflects the number of guidance members agreeing
with the scheduled 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...Flood Watch through Saturday afternoon for NCZ033-035>037-053-
     056-057-063>065-068>072-082-501>510.
SC...None.
&&
$$
SYNOPSIS...JPT
NEAR TERM...SGL
SHORT TERM...SBK
LONG TERM...SBK
AVIATION...SGL