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Next 12 Hours

Forecast data from the National Digital Forecast Database.

5 Day Forecast

• Wednesday
• 
• High: 81 °
• Low: 63 °
• T-Storms

• Thursday
• 
• High: 84 °
• Low: 64 °
• Partly Cloudy

• Friday
• 
• High: 86 °
• Low: 66 °
• Clear

• Saturday
• 
• High: 95 °
• Low: 70 °
• Clear

• Sunday
• 
• High: 95 °
• Low: 68 °
• Chance of T-Storms

Area forecast discussion 
National Weather Service Greenville-Spartanburg SC 
1116 am EDT Wednesday may 23 2012 


Synopsis... 
an upper level low pressure system over the region today will move 
northeast of the area and weaken through Thursday. High pressure 
will build over the area Friday through the weekend...with 
unseasonably warm temperatures expected. The ridge will break down 
Monday into Tuesday...with a cold front approaching from the west 
late Tuesday. 


&& 


Near term /through tonight/... 
at 11 am...the latest infrared/visible products indicate high amounts of 
cirrus/acu persisting in the upper trough...while low level stcu is hanging on 
across many ASOS sites. Still expect a gradual breakup of the clouds 
across the southern zones...but the northern half of County warning forecast area may be broken/overcast 
clouds through most of the day. This will have an impact on temperatures 
and the amount of afternoon destabilization available for afternoon 
convection. Hourly temperatures and sky cover have been adjusted...however 
will wait an hour or so to see the tends before adjusting probability of precipitation and 
maximum temperatures. 


Latest WV imagery reveals the upper low across central SC... 
progressing steadily to the east/northeast. Despite the cold pool 
aloft...there was not much in the way of convection beneath the 
upper low Tuesday afternoon. The models suggest this will be the 
case again today. Based upon the forecast track of the low...the 
highest probability of precipitation will therefore reside across the northern zones. 
However...the atmosphere in the wake of the low is expected to 
become quite unstable this afternoon...so we will retain solid 
chance probability of precipitation across the southern/Central Mountain zones as well. As 
areas beneath the cold pool destabilize this afternoon...convective 
coverage should improve beneath the low...so chance probability of precipitation will be 
featured across the southern NC Piedmont zones. Once again...weak 
shear parameters will limit the severe weather potential...but an 
isolated pulse severe storm or two is possible...as well as locally 
heavy rainfall from slow moving/training cells. 


Lingering middle/high clouds and a fairly moist ground should result in 
another day of near-climatology temperatures in most areas...despite rising 
heights aloft. Convection will diminish during the evening as the 
upper low pulls away from the area. By midnight...coverage is 
expected to be limited to isolated...mainly across the eastern 
zones. 


&& 


Short term /Thursday through Friday night/... 
as of 300 am Wednesday...upper level heights will begin rising 
across the region on Thursday as the remnant of the upper level low 
center continues to pull away to the north and fill. Moist srly flow 
will continue at low levels...with enough instability in the warm 
profiles to warrant isolated to scatttered afternoon and early evening 
thunderstorm coverage. A ridge of high pressure centered over the MS River 
Valley will then build strongly over the eastern Continental U.S. Friday through 
Friday night. Expect isolated...mainly ridge top convection under the 
building ridge on Friday...with profiles largely capped to deep 
convection for much of the area. A tropical system may develop off 
the South Carolina coast on Friday...but with little impact expected 
on the forecast area. Maximum temperatures slightly above normal on Thursday 
will become two categories above normal on Friday. 


&& 


Long term /Saturday through Tuesday/... 
as of 300 am Wednesday...there remains considerable model spread 
with the handling of any tropical feature that might exist off the 
southeast coast at the onset of the period. There 
is...however...good model consensus that the strong 592 dm ridge 
will remain dominant across the east through the weekend. 
Temperatures will be very warm under the ridge axis on Sat...with 
maxes in the lower 90s outside of the mountains and upper 80s in the mountain 
valleys. The upper ridge over the east will slowly flatten Monday 
through Tuesday. A shortwave may dig through the Ohio Valley Tuesday and bring 
gradually improving moisture back to the southern Appalachians late day. 
Diurnal isolated mountain probability of precipitation will be possible each afternoon and 
evening...otherwise profiles look fairly capped for convection. 


&& 


Aviation /15z Wednesday through Sunday/... 
at kclt...brief IFR ceiling recently scattered out...but LIFR/vlifr 
conditions are practically surrounding the terminal this 
morning...so am Leary of going with a straight VFR forecast. Will 
carry a tempo for IFR ceilings for the first hour. Otherwise...scattered 
convection will develop across the Piedmont this afternoon...and a 
tempo for ts has been included by 17z...with prob30 after 21z. 
Convection will gradually diminish with loss of heating. 


Elsewhere...LIFR/vlifr conditions will persist at kgmu/kgsp through 
14z...with VFR expected by 15z. Will also have to watch trends 
closely at kand...as they were reporting sct002 at 11z. Conditions 
should remain in the MVFR range at khky/kavl before improving to VFR 
by 15z or so. Showers will also be seen in western NC this morning. 
Convection will increase in coverage and intensity again this 
afternoon...most likely near kavl/khky...and thunderstorms in the vicinity will be carried 
there by early afternoon. Convection will gradually diminish with 
loss of heating. 


Outlook...diurnal thunderstorms toward the end of the week are more 
likely to be confined to the mountains and foothills. Early morning 
restrictions due to fog are a good bet mainly in the mountain 
valleys. 


An experimental aviation forecast consistency table showing the 
percentage of guidance members agreeing with the scheduled issuance 
category is available at following link (use lower case)... 


Www.Weather.Gov/gsp/aviation/tables.Htm 


&& 


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


&& 


$$ 
Synopsis...hg 
near term...jdl/sbk 
short term...hg 
long term...hg 
aviation...jdl