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189
FXUS62 KCAE 270759
AFDCAE

Area Forecast Discussion
National Weather Service Columbia SC
359 AM EDT Thu Jun 27 2024

.SYNOPSIS...
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Hot and humid conditions continue into the weekend. Afternoon
and evening rain and storm chances start to increase today
through the weekend with noticeable higher moisture building
into the region.
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&&

.NEAR TERM /THROUGH TONIGHT/...
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KEY MESSAGES:
- Hot and humid conditions continue today.
- Increasing moisture leading to scattered afternoon and evening
  storms.

A bit of a pattern change today with an upper trough over the lower
Mississippi Valley digging southward early this morning. This will
lead to increasing moisture over the area as HREF mean indicates
PWATs will climb to above 2 inches by this afternoon and evening.
This will lead to increasing mid and high level cloudiness this
morning before any convection develops across the area which should
at least somewhat limit temperatures. The additional moisture,
however, will prevent dew points from mixing out as significantly as
they have the past few days. While temperatures expected to remain
in the mid to upper 90s today, dew points in the upper 60s to low
70s will lead to max heat indices along and south of I-20 will
generally be between 100 to 105F, which is far from significant
relief. Moderately high confidence that heat indices remain below
heat advisory criteria.

With the aforementioned moisture increase and a channel of upper
level vorticity moving through the area providing a source of lift,
higher coverage of showers and storms expected today. HREF members
indicate moderate instability develops with 60 to 70 percent of
members showing greater than 1500 J/kg of sbCAPE this afternoon.
Highest coverage of storms expected in the southeastern portion of
the forecast area where moisture is highest with initiation
around mid to late afternoon. A marginal risk for severe weather
remains over most of the area today and while deep layer shear
is limited, a sufficiently unstable airmass may lead to isolated
damaging wind gusts in the strongest storms. Storms weaken
tonight with lows in the low to mid 70s.
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.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
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KEY MESSAGES:
- The heat continues, but with a significant increase in
  humidity levels and rainfall chances.

The upper level trough will move through the region Friday,
with the upper ridge then moving back in for Saturday. Moisture
will be on the increase through the period, with pwat climbing
back above two inches both days. With the moisture increase,
afternoon high temperatures should only reach into the middle
90s, but that same moisture increase will bring heat indices
above 100 degrees each day. Saturday could see heat index
readings close to or above advisory criteria once again.
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.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
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KEY MESSAGES:
- Above normal temperatures persist with excessive potential on
  Sunday.
- Slightly cooler temperatures possible to start off the work
  week.

A surface front will be approaching the region on Sunday, but it
is not expected to move through the forecast area until Sunday
night or Monday morning. This front will then stall out across
the southern Midlands and CSRA. Ahead of the front on Sunday,
temperatures will reach into the middle 90s, which sounds good
compared the the heat we have recently been having. However,
there will be a noticeable increase in moisture ahead of the
approaching front, and this is expected to bring heat index
readings up to between 105-113 degrees in many areas. This would
be some of the highest readings so far this season across the
area. If these values continue to be indicated, an advisory
would at least be needed for Sunday. Slightly cooler
temperatures are then expected Monday through Tuesday as the
upper ridge breaks down some, allowing an upper trough to move
through and heights to fall somewhat. Wednesday will see the
return of a building upper ridge, bringing hotter temperatures
back to the area. Highs around 90 possible Monday and Tuesday
before warming back into the middle 90s for Wednesday.

As for rainfall potential, with the front both approaching
Sunday, then stalling out across the southern areas into next
week, expect that scattered showers and thunderstorms will
remain possible through much of the longer term.
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&&

.AVIATION /08Z THURSDAY THROUGH MONDAY/...
VFR conditions with periods of restrictions possible in
thunderstorms this afternoon.

Winds remain elevated tonight with an approaching front leading
to a lingering pressure gradient over the area. As the front
approaches, southerly winds will shift to southwesterly winds
between 5 to 10 knots. The winds in the morning hours along with
a bit drier air at the surface compared to yesterday morning
should prevent restrictions from developing. Scattered showers
and thunderstorms are expected to develop by mid-afternoon and
have included VCTS at all the terminals as a result. Still a bit
of uncertainty as to the exact timing of any restrictions,
however. Thunderstorms will decrease in coverage after sunset
today.

EXTENDED AVIATION OUTLOOK...Scattered showers-storms with
restrictions each afternoon Thursday through Sunday as
additional moisture moves over the region.

&&

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

&&

$$