Area Forecast Discussion
Issued by NWS Columbia, SC
FXUS62 KCAE 271028
Area Forecast Discussion
National Weather Service Columbia SC
628 AM EDT MON JUN 27 2016
A weak trough will develop in the forecast area today
ahead of an approaching cold front. The front will move into the
area Tuesday and bring an increased chance of thunderstorms.
.NEAR TERM /THROUGH TONIGHT/...
Moisture convergence associated with the diffuse front near the
south part of the forecast area has helped cause a few showers
early this morning. This feature may linger through the day.
There may also be a greater chance in the west part this afternoon
as the models develop a weak trough developing ahead of the
approaching cold front. Still, upper ridging should help limit
coverage. Forecasted chance pops with higher values in the south
and west. The models show mainly weak instability associated with
the upper ridging supporting a diminished threat of severe
thunderstorms, but dry mid-level air may aid downdrafts
indicating near-severe wind gusts could possibly occur. Forecasted
highs above the guidance consensus because of the recent bias.
Thunderstorm coverage may increase tonight because of moisture
convergence into a weak pre-frontal trough plus increased moisture
and instability ahead of a shortwave trough in the mid-level
northwest flow. The NAM and GFS MOS support chance pops with the
greater values in the northwest section closer to deeper moisture.
The temperature guidance was close.
.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
The models have been consistent depicting high moisture in the
forecast area Tuesday associated with a cold front. The front is
shown lingering in the area Tuesday night but deeper moisture
shifts east of the area ahead of upper troughing. The guidance
consensus supports likely pops Tuesday and chance Tuesday night.
An average of the GFS and NAM and most SREF members indicate general
rainfall around 0.4 of an inch. However, both the GFS and NAM
have precipitable water increasing over 2 inches so heavy
rainfall may occur with some of the thunderstorms. Followed the
guidance consensus for the temperature forecast.
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
The models show a front lingering near the area through the
medium-range period but deepest moisture appears to remain east
of the area ahead of upper troughing. The GFS and ECMWF MOS have
chance pops during the period. The MOS supports temperatures near
.AVIATION /10Z MONDAY THROUGH FRIDAY/...
VFR should dominate through the period although a few showers and
thunderstorms later today/tonight could result in
restrictions...but confidence low on location.
Mainly thin mid and high level clouds this morning. AGS/OGB will
have MVFR visibility briefly until 13z...then VFR. Scattered
cumulus by this afternoon. Air mass weakly to moderately unstable
this afternoon/evening. High resolution models suggest focus for
afternoon/evening thunderstorms may be in the Piedmont and Upstate
region and more scattered/isolated in the Midlands and CSRA. Will
leave thunder out of terminals although some threat late in the
period. Winds will be variable less than 10 knots.
EXTENDED AVIATION OUTLOOK...The chance for convection will
increase Tuesday as a cold front crosses the region. Otherwise,
diurnal convection possible each afternoon through the period.