Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Columbia SC
731 am EDT Sat may 23 2015
high pressure ridging into the forecast area from the Delaware-Maryland-Virginia
region today will slowly shift farther offshore early next week.
An onshore flow into the forecast area associated with the ridge
will result in higher humidity beginning Sunday. A small increase
in the thunderstorm chance will begin Monday afternoon.
Near term /through tonight/...
the dry pressure ridge extending into the forecast area from the
northeast will dominate through tonight. The models indicate
building upper-level ridging. It will be dry. Used the guidance
consensus for the temperature forecast.
Short term /Sunday through Monday/...
the surface ridge will be slowly shifting farther off the middle-
Atlantic coast with an onshore flow circulating into the forecast
area Sunday through Monday. Moisture should remain shallow because
of upper-level ridging. There may be enough of a moisture increase
combined with heating to help support thunderstorms Monday
afternoon. However...the chance should remain low because of upper
ridging. The NAM and GFS MOS probability of precipitation were 30 to 50 percent. The sref
guidance ranged from near 10 percent in east to 60 percent in the
west. We leaned toward the lower values of 10 to 30 percent
because of expected dominate upper ridging. The temperature
guidance was close.
Long term /Monday night through Friday/...
the GFS and European model (ecmwf) display the ridge circulating an onshore flow
into the forecast area during much of the medium-range period.
However...moisture appears to remain shallow with upper ridging
lingering through the period. The GFS...ECMWF...and ekd MOS have
probability of precipitation of 20 to 30 percent. The MOS has temperatures slightly above
normal through the period.
Aviation /12z Saturday through Wednesday/...
high confidence in VFR conditions through the 24-hour taf period.
Skies will remain clear through morning. Surface winds will be
east/NE this afternoon ranging from 7 to 12 kts. Possibly a few
afternoon cumulus clouds over the area. Winds will be light and
variable tonight with mainly clear skies.
Extended aviation outlook...return flow will allow some low-level
moisture to spread over the area Monday into Tuesday which may lead
to some MVFR restrictions especially during the early morning