Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Columbia SC
228 am EDT Wednesday Sep 2 2015
an upper level ridge centered to our south will shift slowly west
towards Florida and the eastern Gulf of Mexico...while an upper
level trough develops over the East Coast...through Friday. A
relatively dry atmosphere will remain in place over our forecast
area today...ensuring fair weather with a trend towards warmer maximum
temperatures. A slight increase in moisture and some upper energy
expected to lead to a slight chance of mainly afternoon and
evening showers and thunderstorms Thursday and Friday. Indications
of a back door front and increasing moisture may spell increasing
chances for precipitation this weekend into early next
week...along with a trend towards cooler temperatures.
Near term /through tonight/...
a weak surface pressure pattern will remain over our forecast
area (fa) with a relatively dry atmosphere...ensuring fair
weather. Forecast soundings continue to indicate a dry and capped
atmosphere...although a few shallow diurnal showers possible.
Guidance trending a little higher on maximum temperatures. Patchy fog
possible through early this morning. Upper energy and remnant
circulation of former ts Erika...and associated
moisture...rotating around the upper high still appears will be
shunted to the east and remain south of our forecast area as
Midwest upper trough shifts southeast towards the middle Atlantic.
Short term /Thursday through Friday night/...
upper ridge will shift west over Florida and the eastern
Gulf...while upper trough remains over the East Coast...with a
series of disturbances moving through. Models indicate a slight
increase in moisture...which along with some upper lift and
diurnal heating...appears to provide a slight chance of mainly
diurnal showers and thunderstorms.
Long term /Saturday through Tuesday/...
though differences remain between GFS and European model (ecmwf) on specifics and
timing...models continue to generally indicate back door front
moving into or through the region...with closed low aloft and a
low level easterly flow off the Atlantic leading to increasing
atmospheric moisture and probability of precipitation...and trend towards lower temperatures.
Will maintain blend of guidance.
Aviation /07z Wednesday through Sunday/...
weak high pressure at the surface and a building upper ridge
aloft...along with a generally dry air mass should lead to an
uneventful weather day. However...strong radiational cooling early
this morning has already resulted in MVFR visibilities at ags and expect
MVFR/IFR visibilities at ags and eventually later at ogb. Hrrr ceiling
forecast indicates some possible LIFR ceilings moving into ogb around
10-11z but no other guidance showing this and will leave out of
the forecast at this time. Light to calm winds through middle morning
then light and variable winds expected with a prevailing southerly
component to the winds. Precipitable water values around 1.5 inches and lack of
upper forcing suggests convection probabilities are low and will
not be included in the forecast.
Extended aviation outlook...restrictions possible in mainly early
morning with fog. By late in the extended period...afternoon and
evening scattered showers or thunderstorms will be possible.