946 
fxus62 kgsp 051830 
afdgsp 


Area forecast discussion 
National Weather Service Greenville-Spartanburg SC 
230 PM EDT Sat Jul 5 2008 


Synopsis... 
a weak stationary front will remain just north and west of the 
forecast area for the next couple of days. This front will dissipate 
Monday as an upper level ridge builds across the region. High 
pressure will strengthen off the Atlantic coast through the middle 
of next week and moist flow around the western edge of this high will 
keep the atmosphere unsettled through the middle of next week. 


&& 


Near term /through Sunday/... 
band of showers/thunderstorms will move through east County Warning Area this afternoon. Clearing 
behind this band has warmed temperatures quickly to destabilze area for 
convection through this evening. Freezing level around 13kft on laps 
soundings yields 50-55dbz of 31kft for large hail. With moist 
profile all the way up...dcape low today...so damaging winds less 
likely and with wbz up over 12kft it will take a pretty big core for 
hail to reach surface...which is certainly possible. In any case...have 
likely probability of precipitation across County Warning Area until 9pm...chance overnight. Lows from near 
70 Piedmont...middle 50s to low 60s mountains with surface high remaining off 
the southeast coast...moist S flow continues sun with solid chance probability of precipitation 
across area...low end likely across southeast County Warning Area. Highs should reach the 
middle to upper 80s with middle 70s to around 80 mountains 


&& 


Short term /Sunday night through Tuesday night/... 
as of 1 PM Saturday...the axis of the upper trough inches close to 
the southern Appalachians Sunday night...then deamplification begins 
on Monday...however a weak shear axis remains just west of the 
mountains through Tuesday night. The weakening stationary front is 
expected to remain to our northwest from Sunday night through 
Tuesday night...with our area on the warm and moist side of the 
boundary. Instability will be maximized in the Piedmont on Monday 
afternoon and evening...and in the Savannah River valley and 
southern mountains Tuesday afternoon and evening. Chance probability of precipitation will 
be tailored to fit this scenario...as low level winds back Monday to 
introduce a modest upslope component along the southern Blue Ridge 
Escarpment. Wind shear will be a little stronger on Sunday than on 
Monday...but either day will have enough moisture and instability to 
support isolated severe thunderstorms...mainly of the pulse variety. 
Temperatures will run near normal...with a slightly decreased 
diurnal range due to cloud cover. 


&& 


Long term /Wednesday through Saturday/... 
as of 210 PM Saturday...models continue to show good consensus with 
building subtropical ridge and a stacked Bermuda surface hipres over the 
southeast region Wednesday through the extended period. A cold front with 
little upper support is prognosticated to reach the County warning forecast area Thursday. The 00z European model (ecmwf) 
agrees well with the 12z GFS and 12z HPC guidance as far as timing 
the surface boundary north of the County warning forecast area during the afternoon. Wednesday should 
have a normal small chance of strong/severe ts...around 30 
percent...as deep and moist southerly flow sets off scattered afternoon 
convection. However Thursday will be a bit more dynamic and cape values 
will increase due to dewpoint pooling ahead of the front. Will 
expect a bit more widespread coverage Thursday and probability of precipitation were raised into 
the middle 40s across most of the County warning forecast area. No airmass change is expected 
in the llvls Friday as front barley impinges on the area...but the upper 
levels dry out fairly significantly with a 594 dm 500 mb high building 
across the deep south in the wake of the exiting upper trough and a 
strong subsidence zones sets up across the County warning forecast area. This broad stable 
layer aloft should inhibit any good chance of convection for Friday and 
Sat. Probability of precipitation for these two days have been reduced to slight except 
across the NC mountains Friday as lingering low level moisture aided by 
mechanical lifting might be enough to overcome the building cap. Maximum 
temperatures through the period should be right around normal Wednesday and 
Thursday...but a Cat or two above normal is expected Friday and Sat with 
deep middle/upper level drying persisting. 


&& 


Aviation /19z Saturday through Thursday/... 
band of showers with MVFR ceiling/visibility will move through khky and kclt by 
20z with some clearing behind. Look for S to SW surface winds generally 
less than 10 kts. As surface heats up expect resurgence of convection 
later this afternoon-evening across area. Kept likely probability of precipitation over mountains...solid 
chance elsewhere...becoming likely across most of County Warning Area for late 
afternoon-early evening so have vcsh and cumulonimbus clouds all taf sites. Visibility will 
be the main concern late night through early sun with MVFR all 
sites...IFR kavl. With moist SW flow continuing at least chance probability of precipitation 
continue through sun. 


Outlook...little overall chancge through day five. As surface ridge remains 
offshore bringing moisture up over region expect mainly diurnal 
convection with associated hazards. 


&& 


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


&& 


$$ 
Synopsis...sbk 
near term...rb 
short term...jat 
long term...sbk 
aviation...rb