Area Forecast Discussion
Issued by NWS Columbia, SC
FXUS62 KCAE 292047
Area Forecast Discussion
National Weather Service Columbia SC
447 PM EDT Wed Mar 29 2017
The pressure ridge extending through the forecast area tonight
will be off the coast Thursday. Moisture will return Thursday
with a developing onshore flow and warm front just to our south.
There will be a chance of showers and thunderstorms, especially
in the CSRA. The warm front will move through the area Thursday
night, followed by a cold during the day Friday. Numerous
showers and thunderstorms are expected Thursday night into
Friday, some possibly severe. It will be slightly cooler
Thursday and Friday with unsettled conditions, but warmer and
drier conditions will occur over the weekend.
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
High pressure ridging into the area from the north will
dominate. Expect mainly clear skies this evening. Shallow
isentropic lift and moisture flux is forecast to develop late
tonight, especially across the southern Midlands and CSRA into
the Piedmont. Model time-height displays indicate increasing
clouds after midnight with a slight chance of light rain and/
or drizzle toward morning in those regions. With clouds and a
low-level jet, temperatures may stay up a bit but MOS temps
appear on track with lows near 60 although slightly cooler
conditions may occur in the Pee Dee where it should remain
mostly clear most of the night.
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
Weak isentropic lift and low-level moisture flux increases more
Thursday, and rain chances will be on the increase from south
to north as the day progresses. Moisture will ride over a weak
surface wedge north of a warm front, which will stall just south
of the CSRA. With the expected clouds and rain, it`s possible
it may be cooler during the afternoon in the CSRA than Pee Dee
or east Midlands. The wedge will also keep temperatures cooler
in the north Midlands and upstate. It will become increasingly
unstable during the day, and isolated to scattered thunderstorms
will also be possible.
The warm front will lift north during the evening and overnight
hours Thursday night. There is increasing confidence in
thunderstorms through the night and into Friday morning. The NAM
especially is very unstable ahead of the cold front. Models have the
main cold front and upper-level trough moving into the upstate
by 5 AM Friday, and then east of the area by 5 PM. Timing of the
front may not coincide with peak heating, but there will be 40
to 50 kts of bulk shear between 2 AM and 7 AM, and CAPE above
1000 J/kg through 9 AM. Severe thunderstorms will therefore be
possible during this period with the potential for strong
outflow winds and large hail. By late afternoon, moisture and
instability will be moving out of the area as the front pushes
through. The SPC has downgraded the region to a marginal risk
of severe thunderstorms for Friday, due to the faster timing of
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
Dry conditions with light winds will return behind the front as
a high pressure ridge builds in for the weekend. Another system
will approach from the west Monday, which will bring another
chance for showers and thunderstorms through Tuesday.
Temperatures remain above normal through the period with daytime
highs in the mid 70s to low 80s.
.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
High confidence in VFR conditions through 06z. Restrictions
expected toward morning in stratus and possible fog.
Ridging will dominate the area today promoting dry weather.
Clouds and moisture will increase late tonight as the frontal
boundary returns north and weak isentropic lift develops.
Models indicate potential for fog/stratus to develop early
Thursday, although a 25 knot low level jet may limit fog
potential. Confidence is moderately high for at least MVFR
conditions with support from LAMP/HRRR and SREF.
EXTENDED AVIATION OUTLOOK...Restrictions likely in showers and
thunderstorms Thursday afternoon through Friday night as an
cold front crosses the region.