Area Forecast Discussion Issued by NWS Columbia, SC
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000
FXUS62 KCAE 190751
AFDCAE
Area Forecast Discussion
National Weather Service Columbia SC
351 AM EDT Tue Mar 19 2024
.SYNOPSIS...
Some freezing temperatures are possible early this morning
across the northern and western Midlands. Dry weather and warmer
temperatures follow during the middle of next week. Our next
storm system is expected to develop across the southeast late in
the week and bring increased chances of rain Friday and
Saturday.
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.NEAR TERM /THROUGH TONIGHT/...
At upper levels, a Rex block is in place over the W CONUS, with
a deep trough over the E CONUS, funneling cool and dry air into
our region. A tight pressure gradient between the Canadian
surface high to our west, and a front and low pressure offshore,
resulting in breezy conditions accompanying the cold advection.
No frost threat due to wind and dry air, but the cold advection
alone is expected to result in near freezing temps early this
morning over our northern forecast area (FA), where a Freeze
Warning remains in effect. Some indications of decreasing wind
speeds later tonight over land areas, but higher wind gusts over
warmer area lakes expected to continue, so a Lake Wind Advisory
remains in effect until 8 am.
The surface high to our west will shift south towards the Gulf
coast through tonight, while NW flow aloft, and associated lee
side surface trough, will set up to our north, keeping a fairly
tight surface pressure gradient over our region. This is
important as any significant wind would preclude a frost threat
for tonight. Despite guidance consensus min temps in the upper
30s, dry air and wind expected to preclude the need for a Frost
Advisory.
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.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
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Wednesday and Wednesday Night: Persistent northwesterly flow
aloft continues on Wednesday with some confluent 500mb flow
resulting in subsidence and plenty of sunshine across the
forecast area. Surface high pressure remains south of the area
with southwesterly flow providing warm advection and combined
with sunshine should support high temperatures in the lower to
mid 70s.
A weak and dry frontal boundary is expected to push southward
through the forecast area late Wednesday night during the
predawn hours, bringing mainly just some mid and high level
clouds to the region. Winds will shift to the northeast behind
the front by early Thursday morning. A well mixed boundary layer
should limit radiational cooling Wednesday night and expect
warmer temperatures with overnight lows in the lower to mid 40s.
Thursday and Thursday Night: The surface front that pushed
through the region early Thursday morning is expected to stall
to our south across southern GA on Thursday with easterly flow
across our area with the center of high pressure over the Mid-
Atlantic coast. Meanwhile, further west an upper trough over the
southern Plains will gradually shift eastward into the lower
Mississippi Valley Thursday night. Ahead of this system, warm
and moist advection will commence with increasing south-
southeasterly 850mb flow over the top of surface ridging. This
should result in isentropic lift developing over the forecast
area bringing the possibility of light showers to the region
late Thursday night. Temperatures should continue to be warm
across the CSRA and southeast Midlands with cooler temperatures
to the north with highs ranging from the mid 60s to lower 70s.
Increasing clouds and persistent easterly flow Thursday night
will prevent strong radiational cooling and expect lows to range
from the mid 40s north to around 50 in the CSRA.-- End Changed Discussion --
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.LONG TERM /FRIDAY THROUGH MONDAY/...
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Active weather returns to the area on Friday as the southern
stream upper trough moving east through the MS Valley crosses
the forecast area Friday night into Saturday. The main change
from yesterday`s thinking is that rain may linger a bit more
into Saturday as uncertainty has increased a little compared to
yesterday as the EC ensemble has trended a bit slower and more
amplified with the upper trough, closing it off as it moves
offshore Saturday night, while the GEFS ensemble is more
progressive and a bit faster moving the upper trough through the
area. Held on to higher pops on Friday night and keep some pops
across the area through the day Saturday. PWATs rise
significantly on Friday to a peak around 1.5 inches or nearly
200 percent of normal by Friday night.
The initial forcing with this event begins as warm advection,
isentropic overrunning with some possible wedge conditions
developing on Friday (especially in the northern and western
Midlands) then the upper divergence associated with the upper
trough moves through Friday night forcing possible moderate rain
at times, although there are some signals of possible Gulf
Coast convection which could negatively impact rainfall totals.
Relatively high confidence in little to no instability present
so no mention of thunder at this time.
Cooler and drier high pressure builds over the area Sun/Mon in
the wake of departing upper trough with weak shortwave ridging
over the forecast area and surface high pressure building over
the region. Temperatures during this period are expected to be
variable with cooler temps on Friday followed by a return to
near normal temps on Saturday then lower confidence in temps at
the end of the period with large ranges in ensemble guidance.-- End Changed Discussion --
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.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
VFR. Cool and very dry air continues to work into the region.
This, along with wind, will preclude any fog/stratus concerns.
Breezy winds in the near term, with decreasing speeds later this
morning. Winds expected to pick up again during the mid to late
afternoon. Numerous scheduled prescribed burns for today may
provide some locally reduced VSBYs in smoke over some areas this
afternoon and early evening.
EXTENDED AVIATION OUTLOOK...No significant impacts to aviation
expected Tuesday night through Thursday. Some CIG restrictions may
develop late Thursday night. Rain and associated restrictions
Friday into early Saturday.
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.CAE WATCHES/WARNINGS/ADVISORIES...
SC...Lake Wind Advisory until 8 AM EDT this morning for SCZ016-018-
020>022-025>031-035-037-038-041-115-116-135>137.
Freeze Warning until 8 AM EDT this morning for SCZ016-018-020-
021-025-026-115-116.
GA...Lake Wind Advisory until 8 AM EDT this morning for GAZ040-
063>065-077.
Freeze Warning until 8 AM EDT this morning for GAZ040-063-064.
&&
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