Area Forecast Discussion
Issued by NWS Columbia, SC

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FXUS62 KCAE 251513

Area Forecast Discussion
National Weather Service Columbia SC
1113 AM EDT Sun Oct 25 2020

A back door front will slowly slip south through our region today
and tonight. Expect weak high pressure Monday and Tuesday. Tropical
moisture is expected to affect our region Wednesday night through
Thursday night.  Drier air expected to move in for next weekend.


Mid level short wave trough crossing GA will move across the
forecast area this afternoon. Main area of showers affecting
the northern Midlands and Pee Dee Region through early
afternoon. Should see less precipitation coverage for much of
the afternoon. Still some weak instability forecast, so will
continue to mention isolated thunderstorms mainly in the
southern Midlands and CSRA.

A frontal boundary over NC will move southward across SC this
afternoon and evening as a hybrid weak cold air damming
develops. Temperatures should max out near 70 north Midlands and
in the 75 to 80 degree range over the CSRA and southeast
Midlands. The pressure ridge over New England builds south
across the Carolinas overnight and cold advection will develop.
The moisture appears more shallow overnight so although some
lingering showers possible til about 03z, expect mainly patchy
light drizzle at most late tonight. Cooler north of CAE tonight
in the mid to upper 50s as wedge develops and low 60s south.


Weak wedge to remain in place Monday and Monday night.  Some patchy
drizzle possible but overall precipitation chances appear minimal as
upper energy will have moved east and upper ridge begins to build to
our south. Wedge expected to slowly erode Tuesday.


Main forecast challenge will involve tropical moisture/cyclone
moving through or near our region ahead of an upper low approaching
from the west. The closed upper low is expected to move east into
the southern plains/Texas region Wednesday. TS Zeta and
associated moisture will get picked up by the system. Current
official NHC forecast has the cyclone moving WNW into the Gulf
of Mexico then turning north towards the Gulf coast. Models then
turn it NE and accelerate it, with it possibly tracking near or
close to our forecast area. Abundant tropical moisture will
provide increased POPs and a threat for heavy rain. Track of
cyclone will determine possible severe/tornadic threat. At this
time, it appears the main impacts will be in the Wed nt through
Thu nt time frame. Behind the system, cooler and drier air is
expected to enter our region late Friday into next weekend.


MVFR/IFR cig restrictions will continue this afternoon. More
widespread IFR to develop tonight.

Showers will diminish in coverage through the afternoon
as an upper level disturbance moves through the TAF sites. Will
also see a frontal boundary over NC slip southward across the
area late this afternoon and evening setting up a hybrid CAD
pattern this evening and overnight. Guidance consistent with IFR
or LIFR ceilings developing after 00z. Patchy drizzle may
develop behind the frontal passage.

EXTENDED AVIATION OUTLOOK...Restrictions possible through
Tuesday as wedge conditions develop. A storm system could
bring more flight restrictions starting on Wednesday.




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