Area Forecast Discussion
Issued by NWS Columbia, SC

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FXUS62 KCAE 221849

Area Forecast Discussion
National Weather Service Columbia SC
249 PM EDT Sun May 22 2022

A front will push into the region overnight and stall near the
area Monday. Abundant moisture combining with instability and
weak upper disturbances moving into the region will keep the
chance of showers and storms in the forecast through Tuesday.
Another stronger upper trough and cold front will approach the
region on Thursday into Friday bringing elevated chances of rain
before drier air moves in over the weekend.


A fairly complex setup exists over the Southeast currently with
an MCS over eastern SC and another approaching from the
southwest. A mid-level shortwave is causing some weak subsidence
over the CSRA and central Midlands, and this will continue for
most of the afternoon. However, with ample low level moisture
and some surface convergence in spots, spotty showers are still
possible throughout the early afternoon. Showers and
thunderstorm chances increase in the CSRA and northern Midlands
this evening as the MCS continues north and a surface front
stalls just to our north. Severe threats remain low in these
areas but shower coverage is expected to increase. High temps
this afternoon will generally make into the upper 80`s. Shower
chances will linger as the front stalls overnight, so slight and
chance pops remain from the central Midlands to points west and
north; hi-res guidance is in generally good agreement. Low
temps consequently will likely remain in the low 70`s or upper


Monday and Monday night: Upper ridge axis will be to our east
with upper level trough shifting eastward toward the region.
Persistent deep southwesterly flow will support moisture
advection into the region with PWATs rising to as high as
1.8-1.9 inches or around 150 percent of normal. A surface
frontal boundary will be located across the northern Midlands
which will be a focus for convection. The combination of
shortwave energy, the frontal boundary and day time heating with
some instability should support numerous showers with scattered
thunderstorms. WPC continues to highlight our area in a
marginal risk for excessive rainfall which seems reasonable
given the high moisture and upper support. Will focus highest
pops across the northern and western Midlands but have at least
likely pops everywhere by late afternoon. The loss of surface
heating should allow precipitation to diminish after sunset but
showers expected to linger across the north and west closer to
the frontal boundary overnight. High temperatures should be
cooler than previous days due to clouds and rainfall but still
near normal in the lower to mid 80s and overnight lows will be a
bit cooler in the mid to upper 60s.

Tuesday and Tuesday night: Deep moisture will remain over the
forecast area on Tuesday with PWATs quite high around 1.8
inches. There is some uncertainty as to where the frontal
boundary will be and therefore lower confidence in temperatures
depending on which side of the boundary any location may be.
Chances of rain will again remain high with yet more shortwave
energy moving into the area from the southwest during peak
heating and having the boundary as a focus for convection. Heavy
rain potential continues and this is supported by ensemble
probabilistic guidance. Convection should diminish during the
overnight hours as the atmosphere stabilizes. Overnight lows
expected in the 60s.


The extended forecast period continues to be active through the
end of the week as an upper trough to our west slowly moves
eastward with southwesterly flow aloft and deep moisture over
the region into Friday. Wednesday looks to be a day with lower
chances of convection due to a more stable air mass with lower
instability and northeasterly surface flow across the area.
However, moisture advection increases again on Thursday ahead of
a vigorous upper trough that will push a strong cold front
through the region by Friday. Thursday appears to be the best
chance for widespread showers and thunderstorms with severe
weather also possible.

As the upper trough axis shifts east over the area on Friday,
the deeper moisture shifts to the coast with drier air arriving
from the west behind the front. Lowered pops over the weekend
with drier air in place and some upper level ridging building
in. Temperatures this period will generally be near normal.


Generally VFR conditions are expected but with sporadic
restrictions, showers, and thunderstorms through most of the
TAF period.

Ample low level moisture will allow for showers and
thunderstorms later this afternoon. Confidence is low in exact
terminal impacts, particularly for CAE, CUB, and OGB; somewhat
higher confidence for AGS and DNL starting around 22z. So
continued with the VCTS at all terminals but will fine tune
this at next update. Outside of any showers or thunderstorms,
some brief drops to MVFR cigs are possible at OGB as the coastal
thunderstorms slide east. Otherwise south- southwest winds
around 10 knots are expected throughout the afternoon before
weakening overnight.

EXTENDED AVIATION OUTLOOK...Restrictions possible every day as
moisture remains over the area through midweek.




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