Area Forecast Discussion
Issued by NWS Columbia, SC

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FXUS62 KCAE 271031
AFDCAE

Area Forecast Discussion
National Weather Service Columbia SC
631 AM EDT Tue Jun 27 2017

.SYNOPSIS...
A front lingering near the coast will shift farther offshore
tonight. A pressure ridge extending through the Ohio River
Valley today will be in the Mid-Atlantic Region Wednesday and
off the East Coast Thursday. Diminished relative humidity
will be associated with this pattern through Wednesday but
moisture will be on the increase late in the week as the
offshore ridge directs an onshore flow into the forecast area.
This trend will lead to increasing chances of thunderstorms.

&&

.NEAR TERM /THROUGH TONIGHT/...
Drying has occurred behind the cold front. However, there may be
enough recovery of moisture and instability associated with a
mid-level shortwave trough to support a few showers or
thunderstorms this afternoon into the evening mainly in the
north and east sections closer to greater upper lift or deeper
moisture. The HRRR suggested isolated coverage in north and east
sections this afternoon. The NAM and GFS depicted the greatest
instability in the eastern Midlands with surface-based LI
values -4 to -6. The GFS had the greater instability. Forecast
soundings indicated a generally dry atmospheric column and an
inverted-V signature. If thunderstorms do develop with the
limited moisture then strong gusty winds may occur. The
thunderstorm chance should further diminish overnight with the
loss of heating and drying behind the mid-level shortwave
trough.

Followed the guidance consensus for the temperature forecast.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
The models have been consistent with dry high pressure
dominating Wednesday and Wednesday night. Moisture should be on
the increase Thursday especially in the south part of the
forecast area in an onshore flow associated with the ridge off
the East Coast and a mid-level shortwave trough moving into the
region. Followed the guidance consensus and forecasted chance
pops. Also used the consensus for the temperature forecast.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
The GFS and ECWMF display moisture in a southerly flow
associated with offshore high pressure and broad upper
troughing during much of the medium-range period. The pattern
supports scattered mainly diurnal thunderstorms. The GFS and
ECWMF MOS plus GFS ensemble mean indicate chance pops with
temperatures near climatology.

&&

.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
A dry atmosphere is expected to ensure VFR conditions through
the morning. Some mid-level cloudiness may stream across the
region. Upper energy and a surface trough is expected to
traverse the region in the afternoon. Moisture will be limited.
However, some guidance is indicating a few showers and isolated
thunderstorms possible with these features in the afternoon,
mainly east of CAE. However, confidence is too low to mention at
any of the TAF sites. VFR cigs possible later this afternoon but
skies should become more scattered later this evening after the
passage of the upper level energy moves east of the area.


EXTENDED AVIATION OUTLOOK...No significant impacts to aviation
expected through Wednesday. A return flow and increasing low-level
moisture may provide a late night/early morning stratus threat
Thu/Fri. Scattered thunderstorms expected Fri/Sat.

&&

.CAE WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.

&&

$$
SYNOPSIS...99
NEAR TERM...99
SHORT TERM...99
LONG TERM...99
AVIATION...99



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