403
FXUS62 KRAH 092055
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
355 PM EST Tue Dec 9 2025

.SYNOPSIS...
Arctic high pressure will migrate across the Southeast ahead of a
strong, clipper low pressure system that will swing across the Great
Lakes later tonight and Wednesday. A moisture-starved cold front
trailing the clipper low will move across NC Wednesday night.
Another area of high pressure will follow and build across the
Southeast Thursday and Thursday night.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 355 PM Tuesday...

* Unseasonably cold, with refreezing of melting snow cover that will
  lead to a risk of black ice near the VA border

Within a broad trough encompassing ern NOAM, a low amplitude
shortwave perturbation now over the srn Appalachians, and preceding
plume of cirrostratus, will progress ewd and across cntl NC through
early this evening, then offshore. Meanwhile, a more vigorous and
highly amplified shortwave trough will dig from the nrn Plains this
afternoon to the mid MS Valley by 12Z Wed. After a short period of
relatively clear between the two this evening over cntl NC,
additional mid and high-level moisture will be enhanced downstream
of that trough, with a gradual thickening and lowering of associated
ceilings to around 15 thousand ft, through Wed morning.

At the surface, Arctic high pressure now centered at 1023 mb over
the ern Carolinas will continue to weaken while settling across the
South Atlantic states, to the vicinity of nrn FL by 12Z Wed. It will
do so downstream of a now 989-990 mb clipper low that will migrate
from ern ND to MI through the same time. The MSL pressure gradient
and height fields between the two will tighten markedly over cntl NC
overnight, with the development of a swly breeze that may gust at
times into the 20s mph over the srn and nw Piedmont around sunrise,
when an intense, 60-70 kt low-level jet will be in the process of
progressing across the Appalachians. That low-level jet may also
contribute the maintenance of an area of stratocumulus ceilings that
has been slow to disperse today beneath a strong, subsidence
inversion over the wrn Carolinas, as the associated shearing
deformation acts upon a zone of pre-existing 925 mb Fgen and frontal
lift inferred by the strong 925 mb temperature gradient evident
there in 12Z-observed upr air data.

The Arctic airmass overhead, which has supported temperatures this
afternoon only in the mid 30s to lwr 40s, will have an opportunity
to radiationally cool this evening, between the aforementioned areas
of high clouds and prior to the strengthening of the swly breeze.
Quick cooling into the 20s to lwr 30s will probably result, before
temperatures steady or rise after midnight. Lastly, visible
satellite data this afternoon depict a shrinking area of snow cover
confined to the far nrn reaches of the nrn Piedmont and nrn Coastal
Plain, such that refreezing and black ice concerns Wed morning will
be too spatially-limited for any additional Winter Weather Advisory
issuance.

&&

.SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/...
As of 221 PM Tuesday...

A potent mid-level short wave will dive southeast through the Ohio
Valley early Wednesday before pushing across the Southeast US
Wednesday evening.  While mid-level height falls will accompany this
feature, mid to upper flow should be relatively wly, and as such,
most moisture associated with the feature should ring out on the
western slopes of the southern Appalachians.

At the sfc, pre-frontal swly flow will pick up early to mid
Wednesday morning, allowing temperatures to rebound to near normal
(highs in the lower to mid 50s.

Forecast soundings from various models continue to depict the
potential for strong momentum transfer if we can mix deep enough.
Gusts of 30 to 35 mph may be possible late Wednesday morning through
sunset.  Otherwise, a dry cold front will pass through central NC
Wednesday night. Overnight lows will be a bit warmer though as winds
stay stirred behind the front and we only radiate down into the
upper 20s/lower 30s.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
As of 1215 PM Tuesday...

* Temperature roller coaster, below normal Thursday and Friday,
  moderating to near/above normal Friday night through Sunday, then
  falling back to below normal Sunday night through Tuesday.

* Highest chance (slight) for precipitation will be Saturday night
  into Sunday.

Aloft, a s/w traversing the base of the longwave trough will move
across the region on Thu, while the parent low tracks ewd across the
Northeast US/srn Quebec. In the wake of the s/w, the flow will
become gradually more zonal Thu night through Sat. A weak s/w
disturbance may track across the mid-Atlantic late Fri/Fri night.
The longwave trough will again amplify over the central CONUS
Sat/Sat night as a low tracks esewd across Ontario and a nrn stream
s/w tracks esewd from the nrn Rockies to the mid MS/OH Valley. As
the low continues its ewd progression toward the Northeast US, the
s/w will continue ewd across the Appalachians and mid-Atlantic on
Sun, then offshore Sun night. The longwave trough will linger over
the ern US on Mon, with another nrn stream s/w swinging through it
and across the region Mon night/Tue. At the surface, high pressure
will modify as it builds ewd across the region in the wake of the
front Thu and Fri. Meanwhile, a low pressure system will develop off
the central Rockies and move ewd across the Plains and into the mid
MS Valley Thu and Fri. As the low moves east across the region, a
warm front may lift across the area. A trailing, secondary low may
track ewd or newd across the region along the front late Sat/Sat
night, though the track and strength varies between the available
guidance. Regardless, as the low moves out, the attendant cold front
will quickly move across the area, with Arctic high pressure
building in behind it. The center of the high will track east from
the mid/upper MS Valley and across the OH Valley/Great Lakes Sun
night-Tue.

Precipitation: There is a non-zero chance of rain perhaps clipping
central NC counties along the VA border, but for now will keep the
forecast dry. The better chance for rain will be Sat night/Sun,
however chances are slight given the model variability, with a
chance the rain could split central NC entirely (GFS).

Temperatures: Highs mainly in the 40s on Thu, with lows mainly in
the mid to upper 20s. Some moderation could start Fri, with the
potential for highs to reach low/mid 50s across the south. Sat and
Sun will be the warmest days, with temps near to above normal.
Temperatures will drop in the wake of the cold front, with a return
to below normal for Sun night through Tue.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
As of 120 PM Tuesday...

Lingering MVFR ceilings over the wrn Piedmont this afternoon may
scatter, at least temporarily, to VFR late this afternoon and
evening. However, the associated moisture will likely remain trapped
beneath a strong subsidence inversion based in MVFR range and favor
a redevelopment or filling in of associated stratocumulus ceilings
Wed morning, in a zone of frontal lift parallel to the Appalachians
and across the Foothills and wrn Piedmont. That lift may be
augmented by an intense low-level jet that will overspread the
region Wed morning and favor the development of low-level wind shear
and/or strong mechanical turbulence. Momentum from that low-level
jet will increasingly mix to the surface and manifest as a strong
and gusty swly surface wind with heating/mixing Wed afternoon.

Outlook: VFR. Another episode of low-level wind shear will be
possible Fri night.

&&

.RAH WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

SYNOPSIS...MWS
NEAR TERM...MWS
SHORT TERM...Luchetti
LONG TERM...10
AVIATION...MWS