Area Forecast Discussion
Issued by NWS Columbia, SC

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343
FXUS62 KCAE 192333
AFDCAE

Area Forecast Discussion
National Weather Service Columbia SC
633 PM EST Sun Nov 19 2017

.SYNOPSIS...
Dry and cool high pressure will build across the area through
Monday. Moisture will return beginning Tuesday as weak low
pressure develops over the Gulf of Mexico.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
An upper-level trough over the eastern CONUS will move offshore
tonight and surface high pressure over the southern Plains will
ridge into the area. A dry air mass combined with diminishing
winds and clear skies will allow temperatures to cool into the
low to mid 30s. Could even see some readings in the upper 20s
across the Piedmont and Northern Midlands as winds become calm
toward morning. Patchy to scattered frost is also expected. A
Freeze Warning is in effect for the Piedmont and Northern
Midlands with a Frost Advisory for the remainder of the
Midlands and the CSRA.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY/...
Dry and cool air mass over the area Monday with temperatures
ranging from the upper 50s north to the lower 60s south.

Monday night and Tuesday...Low-level moisture expected to
increase with weak isentropic lift developing especially across
the CSRA. Warmer temperatures expected Monday night with less
radiational cooling. A few showers are possible Tuesday because
of weak isentropic lift as a coastal trough develops. Rain
should be very light and limited. Lows Monday night will be in
the 40s.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
Light rain may continue into Tuesday night. Still some model
uncertainty through the extended period with highly amplified
pattern. However, models seem to be a bit more in line than the
past few runs. Models no longer appear to show a cut-off low
forming over the Gulf of Mexico, but do show the highly
amplified trough. Weak low pressure may develop in the Gulf of
Mexico and track northeast. Moisture appears to focus early
along old frontal boundary across Florida to the Georgia and
Carolina coastline. Will keep a small chance for rain mid to
late week including Thanksgiving although confidence remains low
to moderate despite better model agreement. Leaning toward
cooler than normal for Thanksgiving given the pattern and
possibility of rain. Overall, temperatures generally near normal
through midweek, then below normal through Sunday.

&&

.AVIATION /00Z MONDAY THROUGH FRIDAY/...
Expect VFR conditions through the TAF period.

Wind will diminish this evening as the center of the high gets
closer to the area. The center will be near the area late
tonight and Monday. Wind will be light late tonight and Monday.
Strong net radiational cooling and light wind could possibly
lead to early morning fog at the river valley terminals of AGS
and OGB. However, we believed the chance too low to include in
the forecast because of the dry air mass. All the GFS and NAM
MOS plus SREF guidance maintain VFR conditions.

EXTENDED AVIATION OUTLOOK...An onshore flow will develop Tuesday
as the high shifts farther off the coast. An area of low pressure
may develop near the Southeast Coast during the middle of the
week. IFR or MVFR conditions may occur Tuesday through Thursday.

&&

.CAE WATCHES/WARNINGS/ADVISORIES...
GA...Freeze Warning from 4 AM to 8 AM EST Monday for GAZ040.
     Frost Advisory from 4 AM to 9 AM EST Monday for GAZ063>065-077.
SC...Freeze Warning from 4 AM to 8 AM EST Monday for SCZ015-018-020-
     021-025-026.
     Frost Advisory from 4 AM to 9 AM EST Monday for SCZ016-022-
     027>031-035>038-041.

&&

$$



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