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177
FXUS62 KCAE 170808
AFDCAE

Area Forecast Discussion
National Weather Service Columbia SC
408 AM EDT Fri May 17 2024

.SYNOPSIS...
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Chances of showers and thunderstorms will increase this
afternoon as a weak system begins to slowly cross the region
with shower and thunderstorm chances likely lingering into
Sunday. Cooler and drier air moves in for Monday and Tuesday with
temperatures rebounding during the middle of next week as another
ridge moves in from the west.
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&&

.NEAR TERM /THROUGH TONIGHT/...
Upper level ridging currently over the area will continue moving
eastward as the next system moves through the Gulf States.
Through daybreak winds will remain light and variable with
cirrus clouds moving in from the west. Expect some patchy fog to
develop mainly in fog prone locations and near area lakes and
rivers. Overnight lows will be in the low to mid 60s.

Change will begin this morning as winds turn south to
southwesterly. Although speeds will be less than 10 mph this
will begin advecting Gulf moisture into the area. By early
afternoon pwats will have crossed 1.5 inches and 1.8 inches by
early evening. Although this system is lacking a strong trigger
mechanism and mid level lapse rates will be around 5.0 C/Km
there is potential for strong heating should the cirrus be
thinner than expected. Current satellite imagery shows an
extensive cirrus deck over the western and central Gulf Coast
however much of this is due to a weakening MCS. Even with the
MCS cloudiness dissipating as it weakens expect the increasing
and lowering clouds through the day to limit heating and keep
the best chance of thunderstorms across the southern Midlands
and CSRA. SPC outlook has the area in general thunder with a
slight risk over the central Gulf Coast and should this area
become active it is possible for some to push into the CSRA
during the evening into early overnight hours. Overall agree
with the SPC outlook while there is potential across the
forecast area it is limited. Moisture and isentropic ascent
also increase through the evening into the overnight hours and
with pwat values increasing to 2 inches or better at times there
is potential for some locally heavy rainfall. Flow aloft will
be 40 to 50 knots so do not expect any hydro related issues attm
however will continue to monitor. High temperatures this
afternoon will range from the low 80s in the western Midlands
and northern CSRA to the mid 80s elsewhere. Overnight lows will
be in the mid 60s to around 70.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
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Saturday and Saturday Night: Upper trough centered near Arkansas at
the start of the day will move east towards the FA during the
period. Latest guidance suggests that rain on Saturday will be more
scattered in nature than previously thought. With this in mind PoPs
have been lowered, especially during the first half of the day. Many
of the CAMs, such as the 00Z HRRR, suggest there will be a break in
the convection with redevelopment in the afternoon and evening
hours. Thunderstorms will likely increase in coverage later in the
day as the aforementioned upper trough approaches, perhaps providing
enough lift to overcome the lack of instability due to widespread
cloud cover. Another possible deterrent to thunderstorms on Saturday
will be the potential for widespread convection over the Florida
Panhandle which would block gulf moisture from reaching the FA. In
this scenario, we may see only isolated convection until the trough
arrives, as shown in the 00Z NAMNest.

The Day 2 SPC SWO has introduced a Slight (2/5) risk for severe
weather on Saturday for much of the forecast area. While guidance
continues to be quite aggressive with CAPE values, especially across
the southeastern CWA, the previously mentioned concerns provide
reservations regarding the overall severe threat. Modeled soundings
indicate modest directional shear and the presence of mid-level dry
air towards evening suggesting at least a low-end threat for large
hail and damaging winds. Will maintain messaging that a few
thunderstorms may become strong favoring locations south and east of
I-20 and revise as needed with the next forecast package.

Regardless of convective evolution on Saturday, skies are expected
to remain cloudy for the day limiting temperatures to the upper 70s
and lower 80s for most locations. Evening convection will likely
wind down through the overnight as the best lift passes to our east.
Maintained chance PoPs through the overnight period. Lows will be in
the mid-60s.

Sunday and Sunday Night: Not much change in the weather is expected
on Sunday as the upper trough sluggishly moves through the region.
Guidance suggests shower and thunderstorm chances will ramp back up
during the daytime hours. With the upper trough in place, will need
to monitor for potential strong thunderstorms though the SPC Day 3
SWO only has the region in general thunderstorm for Sunday. It`ll be
another cloudy day with below normal daytime temperatures and above
normal temperatures at night.
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&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
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The upper trough sits off the North Carolina coast early next week
favoring a northerly flow over our area. At the surface, an area of
low pressure will also be centered to our east ushering in cooler
and drier air through northerly winds. Monday will likely be the
coolest day of the extended with gradually decreasing cloudiness.
Due to the proximity of the coastal low, a few passing showers
cannot be ruled out on Monday, especially in the eastern half of the
CWA. The low continues to pull away on Tuesday allowing for more
sunshine and warmer temperatures. Weak ridging moves in by Wednesday
allowing temperatures to reach above normal values during the middle
of next week. A cold front approaches late in the period with a
chance of showers and thunderstorms, especially by Thursday.
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&&

.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
Generally VFR conditions expected through the TAF period.

Thin cirrus have begun to overspread the region and will
gradually become thicker through daybreak. Main question remains
will the cirrus be thick enough to limit fog and stratus
development. Although there is currently a 20 knots LLJ shown on
CAE WSR-88D and cirrus moving in satellite imagery also show
some patchy fog developing around AGS. As such have remained
with TEMPO MVFR at AGS/OGB during the early morning and sunrise
hours. Fog and restrictions will mix out quickly with sunrise.
With winds turning S to SW Gulf moisture will be moving into the
area with clouds lowering and thickening as well. Expect showers
to move into AGS/DNL around 23z and spread into the other
terminals by 17/01z with MVFR cigs and vsbys through the end of
the period.

EXTENDED AVIATION OUTLOOK...Increasing confidence in
restrictions in showers and thunderstorms continuing through
Sunday night.

&&

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

&&

$$