Weather

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Area forecast discussion 
National Weather Service Greenville-Spartanburg SC 
314 am EDT Sat Oct 11 2008 


Synopsis... 
a weak area of low pressure and its associated frontal boundary will 
linger off the Carolina coast and weaken through tonight. Moist 
easterly flow across the western Carolinas will give way to milder 
high pressure on Sunday and keep our weather quiet and warm through 
mid-week. 


&& 


Near term /through tonight/... 
for the morning hours...we will have to contend with light rain 
showers or patches of drizzle moving east to west in the circulation 
around the old upper low. The low should move westward today to our 
south and is expected to pull a weak vorticity lobe across the southern 
half of the forecast area. This additional bit of forcing combined 
with the easterly upslope should be able to trigger scattered 
showers over the southernmost zones during the day. Meanwhile...dry 
air will be trying to filter in from the high pressure to the north 
this afternoon and tonight. This should put a damper on shower 
chances over the mountains and the northern zones today...although some 
showers could be forced near the Blue Ridge. A north to south 
gradient in cloud cover will keep temperatures a degree or two cooler over 
the south today...and then a few degrees warmer tonight as well. 


&& 


Short term /Sunday through Monday night/... 
as of 230 am Saturday...the general flow regime for Sunday will 
feature lingering Atlantic fetch...an easterly wind likely lifting 
some degree of mainly shallow moisture across the southern half or 
third of the County warning forecast area. This should result in spotty light showers... 
sprinkles and drizzle...especially in the morning and mainly 
along and southeast of the southern Blue Ridge. Given the orientation 
of the moisture and shower chances...probably will see a non- 
Standard maximum temperature spread...with slightly milder values in 
the drier across across NC...despite lower low level thicknesses in 
this area. Planning on making a downward nudge to maximum temperatures 
across the SW County warning forecast area. Surface ridge center expected to continue dropping 
south through Sunday night...loosening pressure gradient and 
diminishing easterly flow. Sensible weather Sunday night probably 
limited to variable clouds...mainly from terrain lift. Under deep 
layered ridging and more definitive deep drying...going dry forecast to 
continue for Columbus day as maximum temperatures climb to above normal levels. 


&& 


Long term /Tuesday through Friday/... 
as of 230 am Saturday...with some degree of return flow developing 
on Tuesday out ahead of approaching weak cold front...maximum temperatures will 
continue to climb and lingering ridging keeping the forecast dry. A 
reversal of trends was noted in the latest op GFS...now speeding up 
frontal band moisture into the mountains on Wednesday. Best to 
wait until look at new medium range models/ensembles/HPC guidance 
later this morning before changing going dry and warm forecast. With 
the slight uncertainties now introduced for for Wednesday...will not 
make any changes to the late week period either. 


&& 


Aviation /07z Saturday through Wednesday/... 
satellite imagery showed fairly widespread stratocu at several 
levels across the western Carolinas...and observations indicate 
airports have been in and out of MVFR ceilings for the last few 
hours. Think this will continue for the rest of the night and the 
better part of the morning given the wind that is more easterly than 
last night. Models also agree with upper low drifting back to the 
west that another blob of low level moisture will move in from the 
east over the next several hours. Once the sun comes up...any holes 
should fill in quickly with an MVFR ceiling. By the middle part of 
the day the boundary layer should warm enough to lift any ceiling up 
above 3k feet. An upper level wave will rotate around the upper low 
and could trigger some shower activity mainly to the south of 
Interstate 85 but the chances at any terminal are too low to include 
in the taf at this point. Dry air will work its way in from the 
northeast after this wave rotates through...so with sunset the low 
clouds should scatter out and VFR conditions will prevail at all taf 
sites. 


Outlook...high pressure continues to build in from the north Sunday with 
drier high pressure building in early next week. There could be 
ceiling/visibility restrictions Sunday morning across the south as the 
moisture gradient will probably be nearby. 


&& 


Gsp watches/warnings/advisories... 
Georgia...none. 
NC...none. 
SC...none. 


&& 


$$ 
Synopsis...csh 
near term...PM 
short term...csh 
long term...csh/jpt 
aviation...PM