Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Columbia SC
148 PM EDT Sat Aug 1 2015
a stalled frontal boundary will keep the highest chance of showers
and thunderstorms across the southeast midlands through the rest
of the weekend. Above normal temperatures are expected this
weekend and into next week.
Near term /through tonight/...
the upper level pattern features a ridge out west with broad a
trough from the Great Lakes to the East Coast. Water vapor satellite
imagery showed dry air aloft across the midlands and csra.
Weak frontal boundary near the southern tip of the forecast area
this afternoon. Sharp moisture gradient across the region with
deeper moisture to the southeast and dry air northwest. The approach
of weak short wave trough and weak to moderate instability supports
low chance probability of precipitation in the southeast midlands and csra. Seabreeze front
also forecast to move into the eastern midlands. Relatively high
precipitable water remains in that area this afternoon and sounding
analysis suggest any thunderstorms that develop could produce heavy
rain along with slow movement. There is a low threat for strong
winds also given dry air aloft...if entrained into storms. Thunderstorm
threat in the central midlands and west remains low as soundings
appear capped and drier. Kept the north midlands and Piedmont
dry...with probability of precipitation increasing to chance across the southeast portion of
the forecast area.
Met MOS guidance has cool bias with maximum temperatures...so went
closer to mav/ecs guidance. Highs in the 90s this afternoon and lows
in the middle 60s to lower 70s tonight.
Short term /Sunday through Monday/...
the weak frontal boundary will remain across eastern South
Carolina through the period. Models appears to be drier across
central South Carolina and csra and soundings likely capped. Widely
scattered convection confined mainly in the east midlands...lower
csra. Maximum temperatures mainly in the middle 90s...lows upper 60s to
Long term /Monday night through Saturday/...
models have been consistent showing a ridge over the central US
with a broad trough along the East Coast. The frontal boundary
will remain along the coast through early next week before
dissipating. The GFS keeps the area dry through Wednesday. Moisture
returns to the region later in the week. Raised probability of precipitation into the
30-40 percent Thursday through Saturday. High temperatures in the
middle 90s through mid-week...lowering into the lower 90s Thursday
through Saturday. Overnight lows generally in the lower to middle
Aviation /17z Saturday through Wednesday/...
VFR expected at cae/cub. Possible restrictions at times at
ogb/ags/dnl in fog/stratus and/or convection.
Tight moisture gradient across the region...with precipitable
water values ranging from 1.3 inches across the northern midlands to
around 2 inches near ogb. Surface boundary expected to remain in or
near the area. Scattered convection could affect ags/dnl/ogb. Have
indicated vcsh at ogb into the evening. As per guidance and
persistence...have included MVFR fog at ags/ogb 09z-12z.
Extended aviation outlook...restrictions possible in late
night/early morning fog/stratus. Low potential for afternoon and
evening convection Monday and Tuesday.