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358
FXUS62 KCAE 220753
AFDCAE

Area Forecast Discussion
National Weather Service Columbia SC
353 AM EDT Sun Sep 22 2024

.SYNOPSIS...
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High pressure building over the SE US will keep warm conditions
over the Southeast into the first half of the work week.
Multiple shortwaves moving overhead bring at least daily slight
chances for precipitation through much of the week. Confidence
is low in the forecast beyond midweek as uncertainty remains
high with the evolution of an upper trough moving toward the
region and the potential for tropical development in the Gulf.
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&&

.NEAR TERM /THROUGH TONIGHT/...
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Key Message(s):

- Upper ridge persists with above normal temperatures
- Isolated afternoon convection over southeastern Midlands

Upper ridge axis remains to our west over the OH/TN Valleys
this morning. Northwesterly flow aloft continues to allow weak
shortwave energy to ride down the east side of the upper ridge
and there is a weak shortwave noted on WV imagery this morning
over eastern TN. Mesoanalysis shows a maximum in PWATs extending
from northeast NC through the SC Midlands and should shift
southward through the day while some drier air works into the
region from the north. The combination of higher PWATs over the
eastern Midlands and CSRA during peak heating, with the aid of
some larger scale lift associated with the shortwave over TN is
expected to support isolated convection this afternoon, mainly
across the eastern Midlands and CSRA.

Hi-res guidance also supports the idea of isolated convection
across the southeast part of the forecast area late this
afternoon. Temperatures should again be warm and well above
normal under partly to mostly sunny skies with highs generally
in the lower 90s. Tonight, any lingering convection should
diminish quickly with sunset and loss of heating with skies
clearing by late evening. However, expect low clouds in stratus
to possibly develop across NC and into the northern Midlands
late tonight. Temperatures overnight should remain mild with
lows in the upper 60s to around 70 degrees.
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.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
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Key Message(s):

- Upper ridge continues to bring above average temps.
- Afternoon and evening precipitation is possible each day,
  mainly north.

Upper ridging is expected to be over the area as surface high
pressure is filtered into the region from the Northeast to
start the short term period. Meanwhile, an upper trough is
forecast to continue developing over the Upper Midwest. All of
these features slide eastward over the short term period.
Multiple shortwaves are forecast to ride around the periphery of
the ridge as it passes overhead, bringing chances for
precipitation to the northern half of the forecast area each
afternoon and evening. Also, the upper trough is anticipated to
dig southward and assist in developing a surface frontal
boundary, resulting in southwest flow locally. The southwest
flow will likely lead to increased moisture to the region ahead
of the frontal boundary, bringing slightly higher chances for
precipitation on Tuesday. Due to the ridging, temperatures are
expected to remain on the warm side, with highs in the mid 80s
north to lower 90s south each day. Overnight lows remain warm as
well, with lows around 70.
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.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
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Key Message(s):

- Chances for precipitation increase in the long term despite
  forecast uncertainty.


Uncertainty remains pretty high in the long term, leading to a lower
confidence forecast. The two main features causing uncertainty are
the aforementioned upper trough and the potential for tropical
development in the Gulf of Mexico. For the trough, some guidance
shows the trough will continue to most eastward as an open trough,
while others indicate it will close off. For the tropical
development, the National Hurricane Center is not expecting
development in the next 48 hours, but has increased the
probability of development to 70% within the next 7 days. So,
confidence is increasing the some tropical system will develop
in the Gulf, but where it goes and how strong it gets is where
the uncertainty comes in. Assuming something does form, the
strength and track of it will be partly dependent on what
happens with the upper trough. Regardless of what happens, daily
chances for precipitation continue through the forecast period.
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&&

.AVIATION /07Z SUNDAY THROUGH THURSDAY/...
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Generally VFR conditions anticipated through the TAF period.

Satellite imagery showing some mid level clouds north of the
terminals but these should move over the region by sunrise if it
holds together. A 30 knot low level jet should prevent
significant predawn fog but cannot rule out some brief MVFR
vsbys at prone AGS.

A weak shortwave over eastern TN is expected to shift
southeastward through the day and may spark isolated convection
this afternoon during peak heating across the eastern Midlands
and CSRA. Will include VCSH at OGB/AGS/DNL from 19z-00z time
frame. Otherwise partly cloudy skies expected with some mid
level clouds associated with the mid level trough and scattered
cumulus clouds after late morning as temperatures rise. Light
and variable winds around sunrise expected to become more
westerly around 5 to 6 knots through the afternoon with CAE/CUB
possible shifting more northwesterly or northerly as the upper
trough moves through.

EXTENDED AVIATION OUTLOOK...There are no significant concerns
for restrictions at this time.
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&&

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

&&

$$