Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Columbia SC
148 PM EDT sun Mar 16 2014
a frontal system will remain near the southeast coast through
Tuesday. High pressure moving from the Great Lakes region into New
England will push cold air southward and into the forecast area.
The front will begin to move farther offshore late Tuesday.
Near term /through tonight/...
rain has overspread the forecast area associated with strong
isentropic lift north of the warm front. The NAM surface-based Li
pattern indicates the front will remain south of the area. The NAM
and GFS show isentropic lift diminishing late as low pressure
approaching from the west becomes less dominate with cyclogenesis
occurring near the Carolina coast. Cooling will occur as high
pressure centered well to the north wedges into our area. All of
the NAM and GFS MOS support temperatures remaining above freezing.
Elevated thunderstorms are possible but the chance appears low
based on satellite trends. The stronger convection will likely
remain south of the forecast area.
Short term /Monday through Tuesday/...
the front will remain near the coast with cold high pressure
wedging into the forecast area from the north through Tuesday. The
NAM and GFS show isentropic lift generally weak with the deepest
moisture east of the forecast area. Believe additional rain will
be mainly light. The NAM is slower shifting moisture eastward
Tuesday. The NAM and GFS MOS probability of precipitation are close Monday and Monday
night. The NAM displays much higher probability of precipitation Tuesday. Believe an
average of the guidance is best at this time. Mainly the NAM
shows a near-surface below freezing layer in the north part late
tonight through early Tuesday. The warm nose above this layer
appears quite warm. Also believe the more consistent above
freezing GFS MOS temperatures are more likely because of
consistency and cloudiness. We kept the precipitation all liquid
which was also supported be the GFS top-down method using both the
GFS and NAM. We used the GFS MOS for the low temperature forecast.
The colder NAM MOS high temperatures appear better because of The
Long term /Tuesday night through Sunday/...
the GFS and European model (ecmwf) indicate a dry pattern Tuesday night through
Friday. The models show little moisture with a weak cold front
late Wednesday or Thursday. A more significant cold front may
bring showers during the end of the period. The GFS...ECMWF...and
ekd plus GFS ensemble mean support probability of precipitation of 20 to 30 percent.
Temperatures are expected to moderate and be near or slightly
above normal by the end of the period.
Aviation /18z Sunday through Friday/...
radar mosaic and high resolution models suggest moderate rain with
occassional embeded heavier showers will continue through at
least the remainder of the day. Expect continued IFR visibilities in
rain. All terminals are expected to see ceilings drop to IFR in the
near term...with IFR ceilings expected to continue through the taf
period. Area of low pressure to our west will weaken and give way
to new low developing near the coast tonight...allowing wedge/back
door front to shift south through the region late tonight. Heavier
rain expected to shfit towardsth coast tonight...with precipitation
expected to lighten up some over our forecast area tonight. This along
with an increase in wind late tonight and Monday morning behind
the back door front could lead to some improvement in visibilities...however
ceilings are expected to remain low.
Extended aviation outlook...a prolonged period of rain and IFR
conditions expected through Tuesday night.