Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Columbia SC
950 am EDT Monday Aug 3 2015
weak low pressure will lift northeastward across northern Florida
today then along the coast tonight into Tuesday. The deepest
moisture will remain suppressed to the south and east...though
showers are possible across the central and eastern midlands
into the afternoon. Above normal temperatures expected through
Near term /through tonight/...
morning analysis indicates abundant low level moisture in place
across the region with dewpoints in the lower 70s. A weak surface
low located over northern Florida. Aloft...a broad upper trough
extended across the eastern part of the country. Regional radar
indicated showers along the coastal plain into the eastern
midlands...still pushing westward into the central midlands.
The weak low to our south will slowly lift northeastward across
the Florida Panhandle along a weak surface trough near the coast.
The current precipitable water map shows a strong gradient across
the state of South Carolina from 1.3 inches in the upstate to over
2 inches along the coastal plain. The deepest moisture is expected
to remain to our south and east but likely will increase a bit as
the low lifts northward. The best moisture convergence is expected
to be across the coastal plain and eastern midlands...therefore
will be carrying highest probability of precipitation there. The more steady precipitation
should push east northeast this evening away from the area. Isolated
to widely scattered convection is possible elsewhere this
afternoon into early evening due to diurnal heating and moderate
instability. Do not anticipate severe weather but cannot rule out
an isolated strong to severe storm with a damaging wind threat due
to drier air aloft noted on forecast soundings. Temperatures
should be a few degrees cooler today given relatively cloudy start
due to stratus and mostly cloudy skies through much of the day.
Highs today in the middle 90s and lows tonight in the middle 70s.
Short term /Tuesday through Tuesday night/...
as the surface low off the coast continues to shift northeastward
and away from the area...a drier air mass will briefly set in as
precipitable water values fall to around 1.5 inches or less. Weak
northwesterly upper flow along with sunshine and the drier air
will yield hot temperatures once again in the upper 90s to near
100 degrees. The threat of precipitation looks minimal with little
forcing along with the drier atmospheric column. Lows Tuesday
night again in the middle 70s.
Long term /Wednesday through Sunday/...
little changes made to the extended forecast. Upper pattern
features a zonal westerly flow on Wednesday across the region with
weak high pressure at the surface. Isolated diurnal convection
possible but do not expect widespread convection with the lack of
any upper energy moving into the area to enhance any mesoscale
features that may initiate storms. Another upper trough takes
shape over the plains by Thursday and moves eastward into the
Ohio/Tennessee valleys. Moisture will be on the increase again as
low level southerly flow will bring moisture northward from the
Gulf. Highest chance of probability of precipitation will be on Friday as the shortwave
trough pushes across the region acting on the abundant moisture.
The upper trough will persist through the weekend keeping probability of precipitation in
the chance range through the end of the forecast. High
temperatures in the middle to upper 90s mid-week...lowering into the
lower 90s end of the week into the weekend. Overnight lows
generally in the lower to middle 70s.
Aviation /14z Monday through Friday/...
areas of MVFR ceilings to affect ogb/ags/dnl though 15z. As mixing
commences...cloud bases expected to lift to VFR for the afternoon.
A wave of low pressure over northern Florida will track slowly to
the NE across southeast Georgia today...eventually to the SC coast tonight.
Convergence ahead of this system will continue to bring scattered
showers to the eastern midlands...affecting ogb. Early morning
fog/stratus possible Tuesday...but confidence too low to include
at this time given model disagreement.
Extended aviation outlook...restrictions possible in late
night/early morning fog.