River Flood Advisory 8, NWS Columbia, SC

Area Forecast Discussion
National Weather Service Columbia SC
727 PM EST Sat Mar 2 2019

.SYNOPSIS...
An area of low pressure will move across the region Sunday
providing a good chance of showers and thunderstorms, some
possibly severe in the late afternoon and evening. Behind the
low, a cold front will move through late Sunday night, ushering
in some cooler temperatures. An upper disturbance will maintain
some cloudiness and a slight chance of rain Monday night and
Tuesday. Drier and colder air expected to work into the region
for Wednesday and Thursday, with freezing temperatures expected
in the late night/early morning hours. Moisture return expected
Friday and Saturday.

&&

.NEAR TERM /THROUGH SUNDAY/...
Stationary front remains stalled along the Coastal Plain into
the lower CSRA. Satellite imagery showing some mid level clouds
associated with showers that diminished in the past hour but
otherwise mostly clear skies with some patchy cirrus clouds over
the area through midnight. Abundant low level moisture combining
with radiational cooling may provide another night of fog and
stratus development. Expect a gradient in overnight lows with
upper 40s to near 50 northern Midlands to mid-upper 50s
southeast Midlands and CSRA.

&&

.SHORT TERM /SUNDAY NIGHT/...
Weak upper troughiness across the central CONUS. A fast-moving
upper impulse will shift from the Central/Southern Plains east
into the Mid-Atlantic/Carolina coast. A surface low is progged
to develop in response across the W Gulf coast/Lower Miss Valley
and track to the ENE across the Carolinas. Ahead of the low, a
warm front will shift north through our forecast area (FA), with
a cold front trailing the low working south through the FA late
Sunday night. Some shower development along the warm front
possible early, otherwise showers and thunderstorms expected to
move east across the FA mainly late afternoon and evening.
Latest convective analysis indicates weak to moderate
instability, but strong shear, providing a severe threat
including downbursts and possible tornadoes. Latest high
resolution models suggest a convective cluster to our west which
may organize into a QLCS as it approaches and moves through the
FA. Latest SPC Day 2 outlook indicates SLGT risk across the
CSRA into the S Midlands with MRGL risk elsewhere.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
Front to push offshore early Monday. Low level moisture trapped
underneath a mid level inversion along with an inverted surface
trough feature may provide lingering cloudiness Monday. With
strong Canadian high still well to our NW and strong zonal
upper flow over the southern tier of states, will take a while
for coldest air to spill over the mountains. Upper impulse
crossing the region Monday night/Tuesday may provide some
cloudiness and a slight chance of rain. Upper troughiness to dig
into the E CONUS late Tue into Wed and will allow surface high
center to finally get in here late Wed into Thu. Will have to
watch for freeze/frost. NWS Columbia has resumed the Spring
freeze/frost program. E CONUS upper trough progged to lift out
Thu with upper energy and moisture return coming back into the
picture Fri/Sat.

&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
Expect VFR conditions will become IFR late tonight.

A stationary front will extend through the forecast area through
tonight. The front will become a warm front and lift northward
Sunday ahead of a strong cold front. The cold front will sweep
through the region Sunday night.

Fog and stratus will likely become an issue because of high
low-level moisture and convergence along the developing warm front
tonight and linger into Sunday morning. The GFS LAMP has
trended toward more pessimistic conditions. The NAM MOS has been
more consistent with IFR conditions developing. We forecasted
IFR conditions. Expect diurnal improvement with increased
mixing well ahead of the cold front later Sunday morning.
The guidance consensus supported mainly MVFR ceilings. Wind
will be relatively light with a weak pressure gradient through
early Sunday with southerly wind becoming more dominate behind
the warm front later Monday. The MAV and MET MOS support south
wind near 10 knots. Gusty wind may develop if considerable
breaks in the cloudiness develops and increased mixing occurs.
There will be a strong low-level jet associated with the cold
front. Followed the NAM and included low-level wind shear
beginning around 22z. Showers should be most concentrated along
this jet beginning about this time which was also supported by
the high-resolution models. There will also be thunderstorms
but expect these will be scattered with the chance too low to
include in the terminal forecasts at this time. There will be a
possibility of very strong wind aloft mixing down in some of
the stronger showers or possible thunderstorms.

EXTENDED AVIATION OUTLOOK...Numerous showers and scattered
thunderstorms will occur along and ahead of a strong cold front
until around 03z. Low-level wind shear associated with a strong
low-level jet will likely be an issue during the rest of Sunday
night. Drying and VFR conditions will likely occur Monday.
Cloudiness on the backside of developing offshore low pressure
may result in restrictions Tuesday. The low should be farther
off the coast with dry high pressure dominate and VFR conditions
Wednesday and Thursday.

&&

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

&&

Hazardous Weather Outlook...UPDATED
National Weather Service Columbia SC
128 PM EST Sat Mar 2 2019

GAZ040-063>065-077-SCZ015-016-018-020>022-025>031-035>038-041-031100-
Lincoln-McDuffie-Columbia-Richmond-Burke-Lancaster-Chesterfield-
McCormick-Newberry-Fairfield-Kershaw-Edgefield-Saluda-Lexington-
Richland-Lee-Aiken-Sumter-Barnwell-Orangeburg-Calhoun-Clarendon-
Bamberg-
128 PM EST Sat Mar 2 2019

This Hazardous Weather Outlook is for the Midlands of South Carolina
and the Central Savannah River area of Georgia.

.DAY ONE...This afternoon and tonight.

Areas of fog late tonight, possibly dense.

.DAYS TWO THROUGH SEVEN...Sunday through Friday.

Severe thunderstorms possible Sunday afternoon and evening,
producing damaging winds, and possibly tornadoes.

Freezing temperatures expected late Tuesday night/early Wednesday
morning, and again late Wednesday night/early Thursday morning.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will likely be needed Sunday.