Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Columbia SC
1046 am EDT Sat Aug 30 2014
a persistent upper ridge will keep very warm temperatures in the
forecast through next week. Moisture will increase this weekend
into early next week bringing back a low chance of afternoon
thunderstorms and higher humidity.
Near term /until 6 PM this evening/...
middle morning analysis indicates atmospheric moisture continues to
gradually increase across the area with precipitable water values close to 1.5
inches but still remains in a relative minimum across the region
with higher values observed to the north and south of the forecast
area. 14z laps sounding shows significant increase in low level
moisture from the surface to 850mb and with temperatures pushing
into the middle 80s already...convective temperatures are being
reached and stratocumulus clouds have developed. An area of
enhanced cumulus and isolated showers was noted along a north-
south line from Bamberg County southward...possibly associated
with outflow from showers along the sea breeze on Friday.
Expect some of the low level moisture to mix out by this afternoon
with significant dry air in the middle and upper levels and only
isolated showers or thunderstorms are expected in the southeast
midlands with a possible sea breeze and in the csra where deeper
moisture is present. Temperatures will steadily climb into the
lower to middle 90s and humidities will be noticeably higher today
with heat indices in the upper 90s.
Short term /6 PM this evening through 6 am Sunday/...
will hold onto the slight chance early in the evening for the
csra...then expecting conditions to dry out for the remainder of
the night. Guidance and local numbers reasonably close and have
stayed near consensus...around 70 to the lower 70s.
Long term /Sunday through Friday/...
no changes to the extended forecast. Upper ridge continues over
the area through the extended period. However...the overall upper
pattern is not as amplified...but ridge still holds in across the
southeast as short wave move west to east in the flow across the northern plains and
Great Lakes. Low-level moisture continues to slowly increase
through early next week with southeast flow off the Atlantic. With
the passing of each short wave...mainly north of the area a weak boundary
tries to move southward into the region. Have continued with low
chance probability of precipitation through much of the long term period. Best chance
appears to be on Monday with a weak surface boundary SW/NE across
the Piedmont...otherwise just a slight chance/chance through the
remainder of the period. Still looks to be diurnal in nature with
afternoon heating with weak surface convergence and little/no
upper support. Temperatures will continue to be above normal
through the remainder of the long term period. Expect afternoon
highs in the low/middle 90s and overnight lows in the low/middle 70s.
Normals highs are in the upper 80s and lows near 70.
Aviation /15z Saturday through Wednesday/...
some MVFR ceilings through late morning due to increased low level
moisture and low convective temperatures being reached. Expect VFR
ceilings to return to all terminals by 18z with mainly isolated
rain showers/thunderstorms and rain this afternoon into early evening. Chances of rain at
terminals are low and will not include at this time although
ogb/ags/dnl would likely be more likely than cae/cub to observe
precipitation. Winds will be from teh southeast through the
Extended aviation outlook...restrictions possible in late night
and early morning stratus and fog each night. Scattered mainly
afternoon showers and thunderstorms Sunday through Wednesday.