Area Forecast Discussion
Issued by NWS Columbia, SC

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929
FXUS62 KCAE 161803
AFDCAE

Area Forecast Discussion
National Weather Service Columbia SC
103 PM EST Tue Jan 16 2018

.SYNOPSIS...
A cold front will cross the area tonight into Wednesday with
some moisture associated with it, bringing a reinforcing shot
of cooler air for late week. Potential for rain/snow mixture
Wednesday as the front moves through.  Moderating temperatures
and increasing moisture are forecast this weekend into Monday.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
This afternoon: Continued dry and mostly sunny. Highs still
expected in the upper 40s to middle 50s. Winds light and
variable.

Tonight: Cold front will begin approaching the region from the
west. Latest models trending a little wetter along and behind
the front. Temperatures will be tricky tonight. Some weak warm
advection ahead of the front, along with increasing clouds,
should keep much of the cwa above freezing for the majority of
the night. Concern is for areas across the west and north, where
wetbulbing may bring lows down below freezing as the precip
moves into the area. Top-down tools do indicate precip starting
off as rain, then transitioning to a rain/snow mix as temps
approach freezing across the western counties and northern
counties.

Wednesday: The cold front will push through the area during the
daytime hours on Wednesday. Temperatures and precip continue to
be the main issues through the day with the front. Daytime
hours should start off with transition to snow across the
west/north, with a rain/snow mixture possible over the
central/eastern Midlands and CSRA. Expect most areas to
eventually transition to a period of all snow at the back edge
of the precip band before it exits the area. Temperatures over
the Midlands and portions of the CSRA will remain above
freezing, so much of the snow should melt with only minor
accumulations expected. However, across the Northern Midlands,
Pee Dee, and northern CSRA models indicating the potential for
higher snowfall accumulations. Areas bordering the SC/NC state
line could see between 1-2 inches through the event, and with
temperatures there closer to or below freezing, higher
probability of accumulations sticking. A few limiting factors
include PW values only between 0.5 and 0.75 of an inch, which
leads to some lower confidence in final snow amounts, along with
soil temperatures above freezing which should help melt some of
the initial snow. As for amounts, will probably lean towards
WPC snowfall guidance, with local blend added in.

Still making final determinations on warning or advisory areas,
and expect to finalize those later this afternoon.

Temperatures will be falling with the frontal passage and should struggle
to rise much through the day due to cold advection and cloud cover
so have lowered max temperatures a bit with highs expected to
remain in the 30s.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
Cool and dry conditions are expected during the second half of the
week. Arctic high pressure will move into the forecast area
Wednesday night in the wake of the exiting cold front and will
reside over the region into the weekend. Strong radiational cooling
with some lingering cold advection will support overnight lows in
the teens to lower 20s Wednesday night with only slightly warmer
temperatures on Thursday night. Temperatures will begin to moderate
on Friday, with highs in the mid 50s. However, Friday nights
temperatures will still fall below freezing due to radiational
cooling, with lows in the mid 20s to lower 30s.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
Upper level 500mb flow backs from a zonal westerly flow Thursday and
Friday to a more southwesterly direction over the weekend as an
upper trough over the Gulf of Mexico lifts northeastward and de-
amplifies, and the next digging trough moves into the intermountain
west and Plains states. Surface high pressure will have shifted
offshore by Saturday, allowing for warming southwesterly surface
winds, and daytime high temperatures are expected to be in the low
60s. It will be even warmer on Sunday with highs in the mid to upper
60s. Atmospheric moisture rapidly increases going into Monday with
increasing deep southwesterly flow. There will be a slight chance of
rain showers Sunday night, with rain likely on Monday as a deep
upper trough lifting northeastward from the Plains into the Ohio
Valley and Great Lakes region pushes a cold front into the forecast
area. Yet temperatures will remain mild as Monday`s highs should be
in the 60s and Monday night`s lows in the mid 30s to low 40s.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
VFR through early tonight. Later tonight, an approaching
weather system is expected to bring some mid level cloudiness
into the region, with VFR bases early on. By 09z, ceilings
should continue to lower into mvfr category, with light precip
just off to the west of the taf sites. By sunrise, rain/snow
moisture should begin impacting cae/cub/ags/dnl, with mainly
rain at ogb, with mvfr visibility restrictions becoming more
likely with the precip. Restrictions continue through the end of
the taf period.

EXTENDED AVIATION OUTLOOK...No significant impacts to aviation
expected Wednesday night through Saturday.

&&

.CAE WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...Winter Weather Advisory from 4 AM to 2 PM EST Wednesday for
     SCZ015-016.

&&

$$



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