Area Forecast Discussion
Issued by NWS Columbia, SC

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FXUS62 KCAE 231242
AFDCAE

Area Forecast Discussion
National Weather Service Columbia SC
842 AM EDT Wed Aug 23 2017

.SYNOPSIS...
An approaching cold front will cross the area tonight into
Thursday. High pressure will build into the region for the end
of the week...bringing a cooler and drier airmass. Tropical
activity could affect the region next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
A broad upper trough will slowly move through the eastern
states today and tonight...pushing a cold front into the area
tonight. A prefrontal surface trough, weak warm advection,
moderate instability and cooling temperatures aloft will support
deep, moist convection this afternoon. PWAT values ranging from
1.4 to 1.8 inches this morning are forecast to increase to
around 2.0 inches this afternoon. Models indicate the strongest
upper level support to remain north of the forecast area,
although weak upper level energy will affect the forecast area
this afternoon into tonight. Have indicated high chance pops
across the north Midlands and Pee Dee region and low chance pops
across the CSRA. Weak shear and moderate CAPE values support
pulse type convection. However, somewhat dry mid-levels indicate
a threat for a few storms to produce damaging downburst winds.
SPC has outlooked the northeastern quarter of SC in the marginal
category for severe storms.

Expect afternoon temperatures to warm to the mid 90s with
overnight lows in the low to mid 70s.

&&

.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
The cold front is forecast to be over the eastern Midlands
Thursday morning. Weak waves of low pressure developing along
the front will slow its movement. The front should finally move
south of the Midlands and CSRA Thursday night. With drier air
moving in from the west, the greatest chances for showers and
thunderstorms to be across the southeastern part of the forecast
area...closer to the front...Thursday afternoon. Near normal
temperatures in the mid 80s to lower 90s are forecast for
Thursday with lows in the upper 60s and lower 70s Thursday
night.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
On Friday the front will be south of the forecast area bringing
in drier, cooler air. This weekend and early next week models
show high pressure over the Northeast ridging into the mid-
Atlantic. A low pressure system may develop along the old
frontal boundary near coast. Moisture advection over the surface
ridge and a broad upper level trough will bring back chances
for showers and thunderstorms near the end of the extended
period. We`ll also have to watch the remains of Harvey as it
moves northward from the Gulf Coast states by the middle of next
week.

&&

.AVIATION /13Z WEDNESDAY THROUGH SUNDAY/...
VFR conditions expected outside of showers and thunderstorms
this afternoon and tonight.

A front moving into the forecast area today is expected to
increase afternoon and evening thunderstorm threat. Will
continue to handle with VCTS until better certainty in the
timing of terminal impacts. Strong winds will be biggest threat
with gusts around 30 kts possible. Drier air and a low-level
jet should prevent fog/stratus formation on Thursday morning.

EXTENDED AVIATION OUTLOOK...No significant restrictions to
aviation expected through Sunday.

&&

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

&&

$$


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