Area Forecast Discussion
Issued by NWS Columbia, SC
FXUS62 KCAE 262338
Area Forecast Discussion
National Weather Service Columbia SC
738 PM EDT THU MAY 26 2016
High pressure will remain over the forecast area through Friday.
Moisture will increase over the weekend associated with low
pressure nearing the southeast coast.
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
Isolated afternoon diurnal convection across the western part of
the Forecast Area associated with a weak and slowly moving upper
disturbance likely to continue for a couple more hours before
dissipating with the loss of heating. Convection has generally
been low topped within a weakly unstable environment with little
wind shear as cells have been nearly stationary in movement.
Expect skies to clear a bit across the region but maybe staying a
bit higher in cloud cover over the upper CSRA and western Midlands
closer to the upper disturbance. Overnight lows will again be
limited by a 20-25 knot low level jet which will help keep the
boundary layer disturbed. Overnight lows expected to be in the
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
Models continue to show surface ridging coming on off the
Atlantic. Surface low forecast to continue developing across the
western Atlantic east of Florida through the period. This low will
track westward through the period. Models still keep the low off
the coast during the day Saturday, then move it just off the coast
Saturday night. At this time it appears as if Friday and Friday
night will remain dry, due to the influence of the surface high
and upper ridge. Model forecast soundings indicate a mid-level
subsidence inversion or cap becoming more established Friday which
should help diminish the thunderstorm chance also. However by
Saturday the upper ridge begins breaking down as the low off the
coast tracks westward. With easterly flow off the Atlantic, would
expect rain chances to increase during the day on Saturday.
However the best chance for any rainfall will remain mainly across
the eastern portions of the CWA during the day and into Saturday
night. Used a blend of guidance for the temperature forecast.
.LONG TERM /SUNDAY THROUGH THURSDAY/...
Uncertainty enters the forecast as we get into the longer term.
Biggest uncertainty revolves around the track of the low pressure
system forecast to be just off the coast Sunday morning. The gfs
tracks the low inland, then stalls it over the eastern CWA before
it appears to dissipate. The ECMWF is different in that it stalls
it just along the coast during the day Sunday, then tracks it off
to the northeast along the coast of the Carolina`s Sunday night
into Monday. Either way, an increased chance for rainfall appears
likely from Sunday night into Monday. Depending on the track of
the storm, locally heavy rainfall and some flooding could become
an issue in the forecast area.
After Monday, held onto diurnal pop trends for the remainder of
the period, with chance pops during the day, and slight chance
during the overnight hours. Confidence in the longer term forecast
.AVIATION /23Z THURSDAY THROUGH TUESDAY/...
VFR conditions to dominate the period...with early morning MVFR
possible at AGS/OGB.
High pressure ridge remains in control of the area with a weak
disturbance over central GA. Showers remain isolated in the CSRA
early this evening...not expected to impact Terminals and are
expected to dissipate by 01z with loss of heating/forcing. Based
on persistence will forecast a brief period of MVFR fog at AGS/OGB
around daybreak Friday otherwise VFR with mainly clear skies
through the overnight. At most scattered cumulus after
12z...ridge building west from the Atlantic and subsidence
expected. Southeast winds Friday less than 10 knots.
EXTENDED AVIATION OUTLOOK...MVFR fog possible at ags and ogb
early each morning. Increasing confidence in restrictions Saturday
night through Tuesday as a low pressure system approaches from