Area Forecast Discussion
Issued by NWS Greer, SC

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS62 KGSP 190226
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1026 PM EDT Mon Mar 18 2024

.SYNOPSIS...
Drier and cooler conditions into Tuesday as Canadian high pressure
moves over the Southeast.  Warmer temperatures return by mid-week
with continued dry weather.  A low pressure system will bring cooler
temperatures and rain chances back on Friday, with rain chances
potentially lingering into early Saturday.

&&

.NEAR TERM /THROUGH TUESDAY/...
As of 1011 PM EDT: No major changes once again.  Widespread wind
gusts are being reported from ob sites as CAA strengthens within
a tight pressure gradient across the NC mountains.  Temps are on
track, no more than a degree above forecast at most locations.
The Fire Danger Statement has ended, giving way to just windy
conditions overnight.

Otherwise...an upper trof swings over the FA arnd midnight and
this will have the effect of bringing in mid-clouds across the
NC/SC Piedmont and also some low moisture lifting across the TN/NC
mtn spine possibly producing brief periods of snow with little
to no accum thru daybreak. Low-level CAA will continue overnight
and temps will drop below freezing across all areas. The growing
season has started across the srn zones where a Freeze Warning
remains in effect thru the early morning. Another dry day on tap
Tue and RH values will likely drop to 25 percent or less across
many areas. Winds and gusts wont be as strong, so a Fire Danger
Statement may only be needed for NE GA depending on how land
managers feel about fuel moisture levels. This concern will be
coordinated on the evening or midnight shifts. High temps will be
held right around or a little below normal Tue.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
As of 130 PM EDT Monday: Surface high sets up shop over the Gulf
Coast, while broad cyclonic flow aloft continues to church over
the eastern CONUS Tuesday night. Cooler temperatures aloft and
clear skies should allow temperatures to cool off, but radiational
cooling conditions will be limited as the boundary layer will
struggle to fully decouple before daybreak Wednesday as surface
winds remain elevated into the overnight period (5-10 mph). As
a result, overnight lows on Tuesday should be at or slightly
below normal for most locations. Dewpoint depressions will be
too wide to go along with light winds to forecast frost across
the area, especially in the zones that are officially in the
growing season. The airmass will modify very nicely on Wednesday
as heights recover while coinciding with southwesterly WAA and a
west-northwesterly downslope component (850 mb). Lots of sunshine
is expected and should lead to temperatures recovering ~10 degrees
compared to highs on Tuesday. Wednesday afternoon highs are expected
to run 5-10 degrees above normal. Low RH values will be in store
Wednesday afternoon with a well-mixed boundary layer, but winds
should remain light enough to help alleviate fire weather concerns
for most locations. Deterministic models continue to depict a
backdoor cold front dropping through the region late Wednesday
evening as a shortwave trough slips through the northeastern CONUS.
The front will be severely moisture starved, so precip will be hard
to come by as the parent low pushes from Ontario/Quebec into
Atlantic Canada by Thursday and the better forcing/moisture remains
well north of the CFWA. Increasing clouds and WAA will lead to
overnight lows Wednesday to be near-normal.

Conditions begin to take a turn on Thursday as an upper low
gets its act together over the Desert Southwest Tuesday night and
transitions across the Southern Plains and into the Lower MS Valley
by the end of the period. Diffluent flow starts to filter in as
a stout baroclinic zone really activates over the west/central
Gulf Coast. At the same time, a strong surface high will settle
across the Great Lakes region on Thursday. These components come
together at the beginning of the extended period, but in the
meantime, Thursday should remain dry with extensive cloud cover
and continued WAA. Afternoon highs are forecasted to be a few
degrees above normal.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
As of 230 PM EDT Monday: The aforementioned upper low from the
short-term will open up into a shortwave as it encroaches the
region Thursday night into Friday. At the same time, the surface
high over the Great Lakes region will move into the northeastern
CONUS, setting up the stage for a CAD event as the area of high
pressure noses into the region. Good moist upglide and DPVA will
overrun the area as the onset of precip begins to spread from
the southwest to the northeast overnight Thursday. An expansive
precip shield will keep rain over the area through much of the
day Friday as a coastal low begins to deepen over the eastern
Gulf. 30-40 kt south-southeasterly LLJ will help to enhance rain
rates, while locking in the cold, stable dome across much of the
CFWA. Temperatures throughout the vertical profile indicates that
the p-type will remain all liquid outside of the highest peaks
in the northern mountains of North Carolina. Convective rainfall
rates shouldn`t be an issue either as this system lacks elevated
instability. Guidance are in good consensus with the overall
synoptic pattern, but differ in QPF amounts and timing from start
to end. Seems like a good bet that most of the precip will occur
Friday into Friday night, but some models keep precip going into
Saturday morning, which slightly lowers confidence. Either way,
not looking at a hydro threat with this event, just a cold and
dreary day as temperatures Friday afternoon will likely struggle
to get out of the 40s to low 50s over most locations.

The alluded coastal low is expected to move north, up the East
Coast Saturday into Sunday. In this case, near surface divergence
and a downslope component on the backside would allow for the CAD
to erode by the second half of the upcoming weekend. Surface high
quickly dives into the northeastern CONUS by Sunday as thicknesses
begin to recover. High pressure will remain in control through the
end of the forecast period, but the model guidance are showing a
digging upper tough over the western CONUS with an active southern
stream jet by the end of the forecast period. All signs point
to an unsettled weather pattern, but should hold off until after
D7 based on current trends. Temperatures will modify Sunday and
beyond as the CAD erodes and the sensible weather remains dry for
consecutive days as values during the rest of the extended will run
a few degrees above normal with the potential to be a little higher.

&&

.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
At KCLT and elsewhere: VFR expected through the period for all
six terminals.  As high pressure filters into the area overnight
behind a reinforcing cold front, increasingly strong and gusty
NW winds will develop and bring gusts to all the TAF sites.
This should let up before daybreak, except at KAVL, where at least
intermittent gusts will persist into the first part of Tuesday.
Winds will take on a slight S component (though still predominantly
W) Tuesday afternoon as daytime mixing sets in.

Outlook: VFR conditions are expected thru the middle part of the
week. An active frontal system will arrive Thursday night into
Friday, with rainfall and associated restrictions possible.

&&

.FIRE WEATHER...
A dry and cool air mass will continue into the area this evening
associated an area of strong Canadian high pressure. Increasing
mixing heights will continue to mix low dewpts to the sfc leading to
RH values in the low to mid 20s. A tightening pressure gradient will
also create breezy NW winds, with gusts ranging from 20 to 30 mph.
Thus, and SPS for Increased Fire Danger remains in effect across the
NC zones along the northern NC mountains, Blue Ridge Escarpment, and
foothills.

Fire weather concerns may return on Tuesday with RH values falling
into the upper teens to mid 20s across the western Carolinas and
northeast Georgia. Winds will start out NW Tuesday morning before
gradually turning to the SW (east of the mountains) and W/WNW
(across the mountains) Tuesday afternoon. Breezy winds are expected
again on Tuesday with gusts ranging from 15 to 25 mph. These fire
weather concerns will be coordinated with land managers and another
Fire Danger Statement may be needed Tue, most likely across NE GA.

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...Freeze Warning until 10 AM EDT Tuesday for GAZ018-026-028-029.
NC...Freeze Warning until 10 AM EDT Tuesday for NCZ068>072-082-508-
     510.
SC...Freeze Warning until 10 AM EDT Tuesday for SCZ008>014-019-
     104>109.

&&

$$

SYNOPSIS...DEO
NEAR TERM...MPR/SBK
SHORT TERM...CAC
LONG TERM...CAC
AVIATION...MPR
FIRE WEATHER...


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.