Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Columbia SC
920 am EST Wednesday Mar 4 2015
considerable day to day changes expected over the next several days.
A warm front will move north through the region this morning...ahead
of which widespread dense fog is expected. Behind the warm front...
expect warm temperatures and breezy conditions. A slow moving cold
front will move through Thursday...providing shower activity and
isolated thunderstorms. Behind the front...much cooler air will
filter into the region Thursday night and Friday. The front will
stall near the coast Friday before moving farther offshore
Saturday. Moisture return possible Sunday into early next week.
Near term /until 6 PM this evening/...
weak wedge continues to gradually erode from the southeast this
morning. Conditions continue to improve...but a few locations
still have lower visibilities and ceilings. Will allow the dense
fog advisory to expire at 10 am as conditions should have improved
at all sites. Behind the warm front...expect a rapid warm
up...with breezy conditions developing. Model guidance suggests
highs around 80 for a good portion of the forecast area. Vwp this morning at
cae shows 35 kts at 1k feet and 40 kts at 2k feet. Expect some wind
gusts over land areas around 30 miles per hour...but less mixing over Cool
Lake Waters...Lake Murray water temperature 47...expected to result in
less gusts over lakes this afternoon. Criteria for a lake Wind
Advisory is at last 21 kts sustained an/or frequent gusts greater
than 25 kts. Think winds...especially over the area lakes will
remain just below criteria through the afternoon...but it still
will be breezy on the area lakes and over the land areas.
Short term /6 PM this evening through Thursday night/...
warm night expected tonight as slow moving cold front...due to
nearly parallel deep SW flow aloft...will remain to our north
tonight. Front will slowly move south through the forecast area Thursday as
upper energy swings east from the Central Plains to the middle
Atlantic coast. Best precipitation coverage and amounts still appear
will remain just to our north and NE due to main upper energy
remaining just to our north. Instability appears weak...but is
trending up some due to slower frontal movement and warm temperatures
ahead of the front. Introduced isolated thunder Thursday afternoon central
and south forecast area to accompany the showers. Much cooler air to filter
into the region behind the front late Thursday through Friday.
Quite a temperature contrast anticipated across the region Thursday on
either side of the front. Some Post frontal precipitation is anticipated
Thursday night...but at this time it appears that drier air
working in aloft should allow most precipitation to taper off to mainly
drizzle before temperatures can drop low enough over northern portions of
the forecast area for precipitation type to become a concern. However...a period of
light freezing drizzle could be possible for some northern areas.
This will have to be monitored. Breezy conditions possible
Thursday and Thursday night on both sides of the front.
Long term /Friday through Tuesday/...
latest model runs have front stalling or slowly moving near the
coast Friday with some additional upper energy in play. Sref
providing some probability of precipitation for southern areas Friday. Friday appears
quite cool due to cold air mass working in at low levels combined
with some cloudiness and possible light precipitation. Some precipitation type
issues could possibly be in play Friday morning...but
insufficient confidence to mention at this time. Front to push
offshore Saturday with high center building into the middle Atlantic
and southeast Continental U.S.. considerable disagreement among models continues in
latest runs during the Sunday into early next week time
period...leading to very low confidence. For now...continued to
accept HPC guidance...generally providing slight chance probability of precipitation
through the period.
Aviation /14z Wednesday through Sunday/...
high confidence for LIFR conditions through around 14-15z this
morning...then significant improvement through the late modrning
hours. Winds will continue to strengthen ahead of an approaching
cold front this afternoon.
Cold wedge persists across the terminals with the stalled front
across central Georgia. Widespread LIFR visibilities/ceilings at all
terminals to start the forecast. Low level wind shear expected
until The Wedge breaks with a 40-50 knot low level jet atop the
shallow cool layer and light to near calm surface winds. The front
is expected to lift north as a warm front later this morning with
strong southerly winds developing around 15 to 20 miles per hour with some
gusts over 25 miles per hour. VFR conditions expected to return by 15z as
strong warm advection takes place. Low level moisture returns
again this evening with ceilings expected to drop back to LIFR after
03z ags/dnl and by 07z cae/cub/ogb...although think visibilities may not
be as low due to strong pressure gradient and winds staying up.
Extended aviation outlook...widespread MVFR or lower conditions
expected Thursday as another cold front crosses the region.
SC...dense fog advisory until 10 am EST this morning for scz015-016-
Georgia...dense fog advisory until 10 am EST this morning for gaz040-