Wind Advisory 16, NWS Greenville-Spartanburg, SC

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
333 AM EST Wed Dec 4 2024

.SYNOPSIS...
Unseasonably cold air remains in place before a brief warm-up mid-
week. Another cold front crosses the region Thursday dropping
temperatures again to well below normal to start the weekend. A
warmer and wetter pattern is possible by the middle of next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 305 am Wednesday: Latest water vapor imagery depicts NW flow
aloft extending from western Canada through much of the eastern half
of the Conus. A strong speed max embedded within this flow is
currently digging toward the western Great Lakes. This feature is
forecast to push as far south as the Ohio Valley before lifting out
over the Northeast by the end of the period. As the pressure
gradient responds to strong height falls, W/SW low level flow will
steadily intensify across our forecast area through the daylight
hours...supporting a noteworthy warm-up...especially across the
mountains, where a combination of warm advection aloft and downslope
off the major mountain chains is expected to result in temperatures
almost 20 degrees warmer than yesterday. Nevertheless, the max temp
forecast falls a category or two shy of climo.

As the speed max passes north of our region tonight, an associated
cold front will drop toward the southern Appalachians and vicinity.
With dry surface ridging dominating much of the northern Gulf of
Mexico, moisture return ahead of the front will be virtually
non-existent. However, forcing may be sufficient to squeeze out some
light precip across the mountains after midnight...warranting mainly
20-30 PoPs. With surface winds steadily increasing, the air mass
will remain well-mixed overnight except in the most sheltered of
valleys...so light rain will initially be the primary precip
type...with some wintry weather possible in some sheltered valleys
and colder high peaks. Forecast soundings depict shallow moisture
confined to the lower levels with the ice nucleation region
remaining dry...so freezing rain appears to be the most likely
wintry precip type...at least initially...with a brief transition to
snow showers possible as a northwest flow/upslope regime develops
within strong cold advection flow by daybreak. Regardless, this will
be a much less impactful event than the one earlier this week...if
it even happens at all.

The large concern tonight will be mountain winds, with a consensus
of guidance depicting 50-60 kts at 850mb tonight...albeit with the
strongest winds on the warm advection side of the frontal system.
Wind gusts as high as 60 mph will be possible on the high peaks and
ridgetops during the evening, with strong wind gusts likely
descending to the lower elevations toward daybreak as CAA becomes
established and the mountain wave setup improves. Nevertheless,
boundary layer winds will be on the downturn and the pressure
gradient as well as isallobaric gradient will be marginal for even
Wind Advisory-level gusts outside of the high terrain. The wind
potential will be higher farther to the north, and the High Wind
Watch for Avery Co will be upgraded to a Warning for tonight through
much of Thursday. As far as the rest of the mountains, an Advisory
will be hoisted for the remainder of the Blue Ridge/downslope zones
as far south as Buncombe and Rutherford Mountains, while an Advisory
will also be issued for the high elevations of the remaining central
NC mountain counties.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
Key Messages:

1) Cold front crosses the area on Thursday with high winds possible
across the mountains.

2) Dry conditions continue as does the freezing overnight
temperatures.

As of 210 AM Wednesday: Starting at the beginning of this time
period, a tight 850mb pressure gradient should start to broaden as
the low pressure slides out of the NE. High winds across the
mountains and somewhat gusty winds elsewhere should also begin to
decrease. The cold front sweeping across the area looks to be clear
of the area on Thursday as well. Any remaining NW flow snow at the
TN/NC border is also expected to taper off, if any moisture still
remains. Once this passes, the short term looks to be rather quiet.
Behind the front, another round of dry, cold air filters into the
region once again. Surface high pressure, that stubborn and
reinforcing Canadian cP air, returns and keeps the area dry through
Friday night. Any "warm-up" that was realized prior to the front
gets wiped out and a return to colder, below normal temperatures
once more.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
Key Messages

1) A wetter and more unsettled pattern emerges with temperatures
warming into next week.

As of 215 AM Wednesday: Picking up on Sunday, the pattern starts to
reverse course, which is disappointing for the cold appreciators out
there. Synoptically, the flow aloft splits, allowing for a trough
out west to move toward the southeast. Additionally, the surface
high moves off shore and allows for surface winds to become more
southerly, returning moisture to the region. Because of this, long
range guidance increases rainfall probabilities (50%-70%) from west
to east as the system approaches the area Sunday night. Due to the
dry, Arctic air mass being shunted back toward the north,
temperatures are trending warmer, keeping precipitation as liquid.
After Sunday night, the pattern becomes unsettled with a wetter
trend and near normal temperatures for this time of year.

&&

.AVIATION /09Z WEDNESDAY THROUGH SUNDAY/...
At KCLT and elsewhere: VFR through the period, with just some
increasing mid and high-level clouds expected late today. Light or
calm winds this morning will become SW at around 10 kts at most
sites by early afternoon. Some gusts in the 15-20 kts range will be
possible. SW winds are forecast to steadily increase Wed night, with
some gusts of around 20 kts becoming likely after midnight.

Outlook: A cold front will cross the area Thursday, bringing small
precip chances and possible restrictions to the mtns Thu morning.
Winds will become W/NW and increase Thu morning, with very gusty
conditions possible, especially at  KAVL and KHKY. Dry high pressure
will return on Friday and linger thru Sunday.

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...High Wind Warning from 7 PM this evening to 4 PM EST Thursday
     for NCZ033.
     Wind Advisory from 7 PM this evening to 4 PM EST Thursday for
     NCZ048>053-059-501-503-505-507.
SC...None.

&&

SYNOPSIS...CP
NEAR TERM...JDL
SHORT TERM...CP
LONG TERM...CP
AVIATION...JDL

Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
405 PM EST Tue Dec 3 2024

GAZ010-017-018-026-028-029-NCZ035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ008>014-019-101>109-042115-
Rabun-Habersham-Stephens-Franklin-Hart-Elbert-Alexander-Iredell-
Davie-Madison-Yancey-Mitchell-Swain-Haywood-Buncombe-Catawba-Rowan-
Graham-Northern Jackson-Macon-Southern Jackson-Transylvania-
Henderson-Cleveland-Lincoln-Gaston-Mecklenburg-Cabarrus-Union-
Caldwell Mountains-Greater Caldwell-Burke Mountains-Greater Burke-
McDowell Mountains-Eastern McDowell-Rutherford Mountains-
Greater Rutherford-Polk Mountains-Eastern Polk-Cherokee-York-
Anderson-Abbeville-Laurens-Chester-Greenwood-Oconee Mountains-
Pickens Mountains-Greenville Mountains-Greater Oconee-
Greater Pickens-Central Greenville-Southern Greenville-
Northern Spartanburg-Southern Spartanburg-
405 PM EST Tue Dec 3 2024

This Hazardous Weather Outlook is for northeast Georgia and the
western Carolinas.

.DAY ONE...Tonight.

Icy roads are possible across the higher elevations and parts of the
North Carolina Piedmont that received accumulating snow this
morning.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

A hard freeze can be expected again Wednesday morning.

.SPOTTER INFORMATION STATEMENT...

None.

NCZ033-042115-
Avery-
405 PM EST Tue Dec 3 2024

...HIGH WIND WATCH IN EFFECT FROM WEDNESDAY EVENING THROUGH THURSDAY
AFTERNOON...

This Hazardous Weather Outlook is for western North Carolina.

.DAY ONE...Tonight.

Icy roads are possible across the higher elevations that received
accumulating snow this morning.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

Please listen to NOAA Weather Radio or go to weather.gov on the
Internet for more information about the following hazards.

   High Wind Watch.

A hard freeze can be expected again Wednesday morning.

.SPOTTER INFORMATION STATEMENT...

None.

AR