Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Columbia SC
1051 am EDT Monday may 4 2015
dry high pressure will ridge into the forecast area through
Tuesday. Low pressure off the Florida East Coast Wednesday will
likely be off the Georgia and South Carolina coast Thursday.
Showers associated with the offshore system may begin to spread
into the forecast area Thursday.
Near term /through tonight/...
mostly clear skies will continue through tonight as a high
pressure ridge remains in control of the region. Expect some
diurnal stratocumulus to develop through the afternoon
hours...however with a dry airmass in place and a weak cap aloft
do not anticipate any convective showers. Winds will be light from
the south through the day and become light and variable this
evening. Temperatures remain on track for the lower 80s today with
middle 50s tonight.
Short term /Tuesday through Wednesday/...
the models display the dry surface ridge extending into the
forecast area Tuesday weakening Wednesday...but the air mass
remains relatively dry. Model soundings suggest diurnal
stratocumulus and some upper cloudiness associated with a lingering
shortwave trough trapped in the general ridging. All the GFS and
NAM MOS plus sref guidance indicate probability of precipitation less than 20 percent.
The temperature guidance is consistent.
Long term /Wednesday night through Sunday/...
there continues to be high spread in the guidance with the
placement of low pressure forecast near the southeast coast during
much of the medium-range period. The 00z GFS was more progressive
pushing moisture into the forecast area Thursday compared to
previous runs. The models have a tight moisture gradient
associated with this system further diminishing forecast
confidence. The GFS ensemble mean was near 20 percent each day.
The European model (ecmwf) and ekd MOS probability of precipitation were close with values of 20 to 30
percent. The GFS MOS has trended upward to 60 percent Thursday
into Friday with values around 30 percent Saturday and Sunday.
Based on the inconsistency we have forecasted chance probability of precipitation through
Aviation /15z Monday through Friday/...
VFR conditions expected through the period.
High pressure ridge will control the region through the taf period
resulting in mostly clear skies along with light and variable
winds. With a dry airmass in place potential for fog will remain
low...however some patchy fog near ags/ogb after 05/08z will be
Extended aviation outlook...low confidence for restrictions late
Thursday into Friday as moist southerly flow returns to the