Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Columbia SC
1030 PM EDT Tuesday Jun 30 2015
a surface trough along with upper-level troughing will remain in
the forecast area through Thursday. The pattern will support
scattered thunderstorms...especially near the times of maximum
heating. Temperatures will be near normal.
Near term /tonight/...
showers and storms have ended across the midlands and csra as
moisture convergence moved off the coast. Mesoscale- analysis indicated
only weak instability across the midlands with slightly more
instability across the upper Savannah River area. Short wave
energy crossing the midlands will move east of the area around
midnight resulting in partial clearing across the forecast area
during the early morning hours.
Should see overnight lows in the upper 60s and lower 70s. With the
amount of widespread rainfall that occurred...can not rule out some
patchy fog late tonight if skies clear out enough.
Short term /Wednesday through Thursday night/...
models show broad upper troughing over the eastern states through
Thursday with Lee side troughing over the forecast area at the
surface. Shortwave energy will move over the area which may help
to drive convective activity. Expect only isolated activity on
Wednesday with model precipitable waters around 1.5 inches and limited
instability. Moisture will increase from the west late Wednesday
and Thursday as surface low pressure over the Central Plains
shifts east toward the Mississippi Valley. Convection appears more
favorable on Thursday with better moisture across the area as
model precipitable water values are around 1.9 inches. Shortwave energy also
appears a bit stronger on Thursday. Maximum temperatures on
Wednesday and Thursday are forecast near normal...in the lower
90s. Overnight lows in the lower 70s.
Long term /Friday through Tuesday/...
models remain in good agreement showing the upper trough
remaining over the eastern US Friday. The trough flattens out
some late in the weekend. At the surface...a weak surface trough
will remain over the area Friday and Saturday with Bermuda high
pressure over the western Atlantic. A stationary boundary will
remain to our north along the NC/Virginia border on Friday and
Saturday...but may sink south closer to the NC/SC border late
Saturday and Sunday. Diurnal showers and thunderstorms are
expected as moisture remains sufficient over the area. Expect to
see a warming trend over the weekend and into Monday with highs in
the lower to middle 90s and overnight lows in the lower to middle
Aviation /03z Wednesday through Sunday/...
although conditions will remain mainly VFR through the majority of
the period...can not rule out Brier periods of MVFR visibilities or
IFR broken ceilings in areas that have the high clouds clear out
overnight. Sites that have shown IFR ceilings have only had them
briefly...then scattered back out to VFR as higher clouds moved back
in. Due to uncertainty and briefness...will have to monitor for
clearing areas...and update tafs as necessary if it looks to impact
Limiting factor for fog tonight may be the development of a 25 knot
low-level jet. Will not include mention of restrictions at
cae/cub/dnl...but will mention 5sm at usual locations of ags/ogb.
VFR expected through the day Wednesday outside of any afternoon
Extended aviation outlook...chance of restrictions through
the period in mainly afternoon and evening thunderstorms...and
periods of morning fog.