Area Forecast Discussion
Issued by NWS Greer, SC

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FXUS62 KGSP 170721
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
321 AM EDT Sun Mar 17 2024

.SYNOPSIS...
Cloud cover and rain chances return today, with continued warm
temperatures. Drier and cooler conditions will return early next
week as Canadian high pressure builds into the Carolinas. Warmer
temperatures return by mid-week with lingering dry conditions. A low
pressure system will bring rain chances back on Friday.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 318 AM Sunday...The forecast was basically on track, with
some orographic cirrus on the downwind (east) side of the spine
of the mtns. Thicker cloud cover seen on satellite imagery to the
west will steadily invade through daybreak. No changes.

Over the next 24 hours, the confluent zonal flow aloft will
gradually become more cyclonic as a short wave drops down across the
upper and mid-MS Valley region. Two weaker srn stream short waves
embedded in this flow will move across the region...one early in the
day and one late in the day...the latter with some upper support
from the right entrance region of a jet streak moving past to the
north this evening. The second wave will bring a reinforcing cold
front eastward across the fcst area in the evening. An increase in
mostly mid-level cloudiness is a given for today, but the extent
of any light precip is in doubt. Several of the CAMs bring light
precip mainly over the srn half of the fcst area during the day,
but the synoptic scale models are not so...enthusiastic. For the
time being, we play it straight down the middle with what ends up
being mostly a slight chance of rain, but it is worth noting that
many sfc obs across northern MS have the light rain. Perhaps the
CAMs are more correct. We will continue to evaluate. Either way,
precip amts will be very light. The extensive clouds and light
precip should keep temps a few degrees cooler than yesterday,
but still more than five degrees above normal. For tonight, behind
the front, temps will fall back close to normal as high pressure
starts to build in from the west. The coldest air should remain
off to the west through daybreak Monday.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
As of 200 AM EDT Sunday: No major changes for the short term
forecast period. Cool Canadian high pressure will filter into the
central and southern US Monday into Tuesday leading to drier weather
and below normal temps across the western Carolinas and northeast
Georgia. Highs will end up around 5-8 degrees below climo on Monday
and 3-8 degrees below climo on Tuesday. Lows Monday night into early
Tuesday morning will be around 8-10 degrees below climo and near or
below freezing across the CWA. Since the growing season has started
across Northeast Georgia (outside of Rabun and Habersham Counties),
the SC Upstate (outside of the SC mountains), the southern NC
Foothills, and the southern NC Piedmont, a Freeze Watch was issued
for these areas. This will likely be upgraded to a Freeze Warning if
model trends hold regarding freezing temps. Lows Tuesday night will
be around 10 degrees warmer so additional freeze products should not
be needed. A tight pressure gradient will lead to breezy NW winds on
Monday across the forecast area, but they look to remain below
advisory criteria for now. Winds will gradually decrease in speed
Monday night into early Tuesday morning, but lingering wind gusts
are expected across the NC mountains. Winds pick up again slightly
Tuesday into Tuesday night, especially across the mountains.
However, wind speeds should generally be lower compared to Monday.
The dry airmass combined with breezy winds each afternoon will lead
to fire wx concerns on both Monday and Tuesday. RH values look to
drop into the low to mid 20s east of the mountains on Monday, and
the upper teens to mid 20s across much of the forecast area on
Tuesday.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
As of 230 AM EDT Sunday: No major changes for the first half of the
long term forecast period. Above climo temps return middle of the
week despite a dry cold front tracking across the forecast area on
Wednesday. Low-end wind gusts will linger across the NC mountains on
Wednesday, with gusts returning in the late morning/afternoon hours
elsewhere thanks to the cold front. RH values will recover somewhat
Wednesday afternoon, but are still expected fall into the mid to
upper 20s east of the mountains. Thus, fire wx concerns will return
once again Wednesday afternoon. Wind gusts will finally taper off
area-wide throughout Wednesday evening. Dry high pressure builds in
from the north behind the departing front on Thursday. This will
lead to slightly cooler temps on Thursday compared to Wednesday.
With winds gradually turning SE Thursday afternoon, RH values should
climb into the upper 20s to lower 30s east of the mountains. Since
winds will be lighter on Thursday, this should limit fire wx
concerns.

A low pressure system lifting NE out of the Gulf Coast may bring
rain chances back to the western Carolinas and northeast Georgia the
second half of the long term. A sfc high passing to the north may
also allow cold air damming to develop east of the southern
Appalachians on Friday ahead of the low. The 00Z GFS and Canadian
continue to trend wet, but the 00Z ECMWF is now showing dry
conditions across the CWA. Per model disagreement, capped PoPs to
chance Friday into Saturday. Instability still looks to be lacking
with this system, especially with CAD in place, thus maintained the
no thunder mention at this time. Highs look to end up below climo on
both Friday and Saturday thanks to precip, cloud cover, and the
wedge.

&&

.AVIATION /08Z SUNDAY THROUGH THURSDAY/...
At KCLT and elsewhere: VFR at all terminals through the period,
with only mid and high cloudiness expected. Clouds invade from the
west toward daybreak with wind remaining light SW. Weak forcing
and moisture return could result in the development of light rain
showers across northeast GA/Upstate SC/CLT metro in the late morning
through late afternoon hours, but no vis restrictions are expected
and the ceiling will most likely remain at mid-levels. The rain may
not be anything more than occasional sprinkles. At this time, the
wind could come around to WNW east of the mtns, but think most of
the time the direction will be WSW. Occasional gusts are possible,
but not likely. The wind direction should come around to WNW or
NW in the early/mid evening.

Outlook: Dry high pressure will build in Sunday night with gusty
winds lasting into on Monday.  VFR conditions will continue through
the middle of the week.

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...Freeze Watch from late Monday night through Tuesday morning
     for GAZ018-026-028-029.
NC...Freeze Watch from late Monday night through Tuesday morning
     for NCZ068>072-082-508-510.
SC...Freeze Watch from late Monday night through Tuesday morning
     for SCZ008>014-019-104>109.

&&

$$

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


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