891
FXUS62 KGSP 300727
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
327 AM EDT Mon Sep 30 2024

.SYNOPSIS...
A large area of low pressure will slowly drift east out of the Ohio
Valley today leading to another round of scattered light showers,
mainly across the mountains. The upper low will finally lift north
and east of the area on Tuesday before a weak, moisture starved cold
front tracks across the area on Wednesday. Dry high pressure will
build in behind the departing cold front Thursday into Friday before
another cold front tracks across the area early Saturday, bringing
cooler temperatures behind it on Sunday.

&&

.NEAR TERM /THROUGH TONIGHT/...
Key Messages:

1) Scattered Showers Expected Again this Afternoon and Evening,
Mainly in Western North Carolina

2) Rainfall Amounts will Remain Light (Generally Half an Inch or
Less)

3) Patchy Fog and Low Stratus Possible this Morning and Again Tonight

As of 300 AM EDT Monday: Seeing thick cloud cover across portions of
western North Carolina this morning, with thick cloud cover lifting
north across the South Carolina Upstate and northeast Georgia. This
will act to limit radiational cooling through daybreak, keeping lows
this morning around 10-13 degrees above climo. Patchy fog and low
stratus should develop across western North Carolina later this
morning, with low stratus developing mainly south of I-85 in the
South Carolina Upstate. Pockets of patchy fog should develop across
portions of the SC Upstate as well. Already seeing fog at the
Pickens County Airport as well as the Jackson County Airport this
morning. Light showers have been lifting northeast across the Upper
Savannah River Valley the last few hours and are currently grazing
Elbert, Abbeville, and Greenwood Counties. The HRRR has this
activity continuing to lift across the eastern fringe of the
forecast area through the morning hours, reaching Charlotte around
daybreak.

An upper low tracking will track east out of the Ohio Valley towards
the Mid-Atlantic through the near term. This will allow for another
round of scattered showers to develop this afternoon and evening,
mainly across western North Carolina. Have the highest PoPs (likely,
55%-65%) mainly north of I-40, with lower PoPs (chance, 15%-40%)
elsewhere. Rainfall amounts will remain light, generally half an
inch or less. Highs will be similar to yesterday and a few degrees
above climo. Dewpoints will be a bit higher compared to yesterday so
it should be a little more humid today. Cloud cover looks to thin
out gradually by this evening, mainly east of the mountains, before
gradually filling back in overnight into daybreak Tuesday. This will
act to keep lows tonight ~10-12 degrees above climo. Low stratus and
patchy fog may develop again overnight into daybreak Tuesday.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
As of 230 AM EDT Monday: Isolated to scattered showers are expected
Tuesday, mainly across the mountains and I-40 corridor as moisture
rotates around the departing upper low and across the area. With
little in the way of instability, thunderstorms aren`t expected and
QPF should be light. A weak short wave pushes a weak, dry cold front
across the area Wednesday. Highs will be near to a few degrees above
normal. Lows will be around 5 degrees above normal.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
As of 245 AM EDT Monday: A weak upper ridge builds over the area
Thursday then moves east as a series of weak short waves cross the
area Friday and Saturday with a weak cold front crossing the area
Saturday. Weak moisture return and forcing could lead to spotty
showers, especially on Friday. A dry forecast is currently expected
on Sunday with the front to our south. Guidance is in better
agreement regarding the potential tropical cyclone developing in the
Gulf of Mexico. The short waves moving across the eastern CONUS keep
any developing system to our south, moving east across central
Florida. Of course, everyone in the Western Carolinas and Northeast
Georgia should keep up with the latest forecasts. Highs remain near
to slightly above normal through Saturday then drop a little below
normal for Sunday. Lows remain nearly steady 5 to 10 degrees above
normal.

&&

.AVIATION /08Z MONDAY THROUGH FRIDAY/...
At KCLT and elsewhere: Dry and VFR across the terminals as of 06Z.
KAND should see some patchy, MVFR fog develop and linger through
daybreak. KAVL and KHKY are most likely to see both cigs and vsbys
lower to MVFR to IFR levels around daybreak so have TEMPOs to
account for this at both terminals. KCLT may see MVFR cigs develop
around daybreak and the last few runs of the HRRR continue to show
-SHRA tracking over KCLT later this morning so have a TEMPO to
account for this from 11Z-15Z. Fog should lift out between 13Z-15Z
across the NC terminals, with MVFR cigs lingering through the
morning hours before lifting to VFR levels this afternoon. The SC
Upstate sites should see cigs remain VFR through the 06Z TAF period.
Scattered -SHRA is mostly expected to develop across mainly the
mountains this afternoon/evening so have a PROB30 at KAVL from 18Z-
20Z. Maintained a PROB30 from 20-24Z at KHKY but confidence on this
is lower as activity may not reach the terminal. Winds will be calm
to light and VRB through the early morning hours before picking up
out of the S/SW by mid-morning. KAVL will see winds turn NW late
this afternoon into tonight. Winds across the SC Upstate terminals
will turn W/WSW this evening into tonight, becoming light. Winds at
KAVL and KCLT should turn calm to light and VRB this evening into
tonight.

Outlook: An upper low will slowly push north and east of the
Appalachians on Tuesday, keeping scattered -SHRA around. Drier
conditions return mid to late week as high pressure builds into the
region. Fog/low stratus will be possible overnight into daybreak
each day, mainly in the mountain valleys.

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...None.
SC...None.

&&

$$

SYNOPSIS...AR
NEAR TERM...AR
SHORT TERM...RWH
LONG TERM...RWH
AVIATION...AR