Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Columbia SC
436 PM EDT Friday Jul 25 2014
a nearly stationary frontal boundary over south South Carolina will
dissipate Saturday. Thunderstorms will be isolated Saturday as
moisture becomes more limited. Weak upper level ridging will
bring hot and dry weather Sunday. Another cold front will cross
the region late Monday with a chance of thunderstorms.
Near term /until 6 am Saturday morning/...
latest surface analysis suggests at least two surface
boundaries...one appears could be the main front just south of the
forecast area (fa)...with a differential heating boundary caused by
earlier cloud cover across our south central forecast area. Radar indicates
convection developing along these features...with better coverage
across the southern area where better low level moisture exists.
Satellite water vapor imagery indicates dry air aloft working
in...which could reduce areal coverage for much of our forecast area...but the
moisture boundary aloft coincident with surface boundaries could
provide a threat of an isolated severe cell. At this time...it
appears the best threat of isolated severe or locally heavy rain
will be mainly south and east of our forecast area...and possibly
our southeast forecast area. Widespread low cloudiness north of the front across the
northern midlands beginning to show some indications of gradually
dissipating. After diurnal convection dissipates this
evening...expect fair weather overnight.
Short term /6 am Saturday morning through Sunday night/...
flat ridging builds across the southern states Saturday through
The cold front will become stationary/diffuse across the southern
South Carolina Saturday with deeper moisture to the east although
the air mass will be weakly to moderately unstable. Convection
more isolated on Saturday and Sunday with weaker forcing.
Temperatures above normal for the weekend. Prefer warmer mav
guidance through the period with recent cool bias of the met.
Long term /Monday through Friday/...
models continue to trend toward an amplification of the long wave
pattern with a ridge in the west and a trough in the east. This is
a rare pattern for July.
The upper pattern once again amplifies early next week with a
ridge in the west and a deep trough in the east. This should push
another cold front through the area late Monday into Tuesday.
There should be a good chance for showers and thunderstorms Monday
ahead of the front then mainly dry for Tuesday and Wednesday as
high pressure builds in from the northwest. Both the GFS and European model (ecmwf)
bring increasing moisture to the region Thursday into Friday as
high pressure wedges in from the north with a linger trough offshore
resulting in a moist easterly flow.
Above normal temperatures will continue Monday ahead of the front
with highs in the upper 90s. Cooler temperatures are indicated
Tuesday through Friday with highs in the middle/upper 80s and lows
mostly in the 60s.
Aviation /21z Friday through Wednesday/...
21z radar reflectivity shows main convective activity moving east
out of the forecast area with a few lighter cells mainly well south
of I-20. Surface boundaries set up across portions of the central
and southern forecast area...south of cae/cub...but near
dnl/ags/ogb. Low cloudiness with MVFR ceilings near cae/cub dissipating
and shifting north of cae/cub. Scattered showers and thunderstorms
expected to affect mainly ogb through 00z. Keeping vcsh at ogb
through early evening...VFR elsewhere.
Guidance generally keeps any stratus tonight north of the
terminals. Light winds and possibility of clearing tonight could
promote fog formation...though some questions regarding extent of
any lingering cloud cover. For now...will indicate tempo period of
Weakening front and best moisture expected to push to the south and
east of the terminals Saturday. VFR.
Extended aviation outlook...minimal convection expected Sat/sun.
Better thunderstorm chances Monday with approaching cold front.