Area Forecast Discussion
Issued by NWS Columbia, SC

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FXUS62 KCAE 260928

Area Forecast Discussion
National Weather Service Columbia SC
428 AM EST Mon Feb 26 2024

High pressure along the coast will shift further offshore
today. Southwest flow across the region through midweek will
promote above normal temperatures and a chance of showers. As a
cold front moves into the Southeast on Wednesday expect gusty
winds and another round of showers. Unsettled weather remains in
place for the remainder of the long term.


Morning analysis shows surface high pressure located just
offshore ridging into the forecast area. Aloft a generally
zonal 500mb flow pattern is in place with slight northwesterly
flow across the Carolinas this morning. A relatively dry air
mass is in place with PWATs around 0.4-0.5 inches. Satellite
imagery and MRMS shows an area of mid level clouds across the
northern Midlands with some isolated showers just north of our
area associated with weak shortwave energy in the northwest
flow moving across the eastern TN and the central Appalachians.

Upper level flow will back more westerly today with the light
showers near the northern Midlands and mid level clouds shifting
northeastward as the shortwave energy moves toward the NC/VA
coast. Skies should clear through the day allowing for plenty of
afternoon sunshine. Light winds this morning should pick up
from the south to around 10 to 15 mph with some gusts over 20
mph as the pressure gradient increases between high pressure
offshore and low pressure moving into the Northern Plains. The
combination of clearing skies and increasing southerly flow
should yield warmer max temperatures in the lower to mid 70s.

A digging upper trough over the middle of the country will
support increasing and deepening southwesterly flow across the
MS/TN valley this evening with increasing PWATs over our
forecast area tonight. Low level moisture advection may yield
some stratus clouds arriving around sunrise on Tuesday but also
expect some increase in mid level clouds after 06z. The
combination of increasing clouds late tonight and a 30 knot low
level jet keeping the boundary layer mixed should result in
warmer overnight lows tonight in the mid to upper 40s.


Tuesday and Tuesday Night: SW flow strengthens over the
Southeast Tuesday leading to an increase in atmospheric
moisture. Mean PWAT values from the SREF exceed 1 inch after
daybreak Tuesday, favoring deeper moisture across the Upstate.
Broad diffluent flow over the region supports synoptic scale
ascent. As the low levels gradually moisten through the morning
we should see showers develop and overcome the low level dry
air. The lack of a prominent low level feature should keep
convective coverage scattered in nature. With deeper moisture
across the western FA and 850 mb ridging to the east, it seems
the greater rain chances will be over the western FA stretching
north to the NC/SC border. Mostly cloudy skies and showers will
hinder daytime heating, however SW flow should still allow for
highs in the upper 60s north to mid 70s south. Moisture
advection weakens during the afternoon and evening along with
rising 500 mb heights. This points to decreasing rain chances
for Tuesday night. Temps will be mild Tuesday night as winds
pick up ahead of an approaching front. Expect lows above normal,
mainly in the mid 50s.

Wednesday and Wednesday Night: An upper level trough will move
across the central US and lift into the Great Lakes region on
Wednesday. A trailing cold front will work its way across the
Southeast. With the strongest dynamics well north of the area
frontogenesis is weak and moisture advection ahead of the front
is modest. This may indicate that shower coverage will be
limited ahead of the front for Wednesday afternoon and overnight
as the front passes. Only about 10 percent of SREF members have
MUCAPE values above 100 J/kg through Wednesday and Wednesday
night, so the chance of thunderstorms is low. It will be breezy
on Wednesday ahead of and behind the front. A 50 kt 850 mb jet
moves over the region in the morning which may prompt a Lake
Wind Advisory with gusts from 25 to 35 mph possible. Despite
mostly cloudy skies, temperatures will be warm again with highs
on Wednesday generally in the 70s. Overnight, the front and any
remaining showers will moves east and winds slacken as the
pressure gradient relaxes.


Cool, dry air filters into the region Thursday as the axis of
an upper trough moves off of the East Coast. It won`t be long
before moisture returns to the area. Surface high pressure moves
offshore on Thursday night and Friday leading to moisture
riding over the lingering ridging. This setup favors overcast
skies and cold air damming with temperatures cooler than normal.
The depth of the moisture over the ridge is uncertain but there
is a chance of rain which could reinforce the cold air damming.
This may continue into Saturday with at least shallow moisture
remaining in place. We favored the cooler end of the guidance
spectrum given the tendency for models to erode CAD conditions
earlier than actually occurs. The remainder of the weekend and
early next week also look unsettled with PWAT values around
normal and shortwave troughs supporting shower activity. This
setup favors at least a chance of rain through the end of the
long term.


VFR conditions expected through the 24hr forecast period.

High pressure is centered off the coast with a light southerly
flow across the region. Satellite imagery shows some mid/high
level clouds associated with some weak shortwave energy in the
northwest flow aloft. Overall the air mass remains relatively
dry. Expect some scattered high clouds to remain over the region
through sunrise then skies should become mostly sunny by this
afternoon. Dewpoints have come up from the afternoon but cross
over temps still low enough that fog should not be much of a
concern and no guidance shows any fog at terminals. Light to
calm winds through sunrise will then pick up from the south to
around 10 knots with some gusts up to 20 knots possible through
the afternoon.

EXTENDED AVIATION OUTLOOK...No significant impacts to aviation
expected through Tuesday. Strong gusty winds possible Wednesday
ahead of a cold front. Restrictions possible Wednesday night with
showers as the cold front moves through. Restrictions possible
Friday as moisture increases.




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