290
FXUS62 KRAH 032322
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
620 PM EST Wed Dec 3 2025

.SYNOPSIS...
Continental Polar high pressure will migrate across the Southeast
through early Thursday. A dry cold front will lead Arctic high
pressure across and offshore the Middle Atlantic later Thursday
through Friday, while weak waves of low pressure will track along a
wavy frontal zone from the northern Gulf to offshore the Southeast
coast.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 1240 PM Wednesday...

* Unseasonably cold with variable cloudiness through the overnight
  period.

A broad area of 1022mb high pressure leaking across the southern
Appalachians will continue to drift eastward throughout the day
before becoming increasingly diffuse by Thurs morning. Patches of
flat strato-cumulus clouds, visible on satellite imagery over the
western Piedmont into the Sandhills and Coastal Plain, will provide
locally greater coverage of partly to mostly cloudy skies through
the afternoon before gradually thinning late this evening into
tonight.

Light surface winds will become more south to southwesterly through
the afternoon and keep surface dew points fairly steady as moisture
north of the stalled occluded front to our south counteracts the
very dry air just above the PBL. Limited horizontal moisture
advection is expected overnight within the weak pressure gradient,
but relatively moist afternoon crossover temperatures and pockets of
heavily saturated soils from Tues rainfall, may result in patchy
fog. Widespread fog is not anticipated as waves of cirrus with
varying thickness shift over the region overnight and should provide
an unfavorable factor to an otherwise excellent radiational cooling
night for radiation fog. Lows tonight will settle in the mid 20s to
low 30s.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
As of 326 PM Wednesday...

* Increasing clouds and milder/more-seasonable Thu

* Precipitation developing, including a rain/snow mix that will
  probably transition to all snow for several hours across the nrn
  Piedmont, late Thu night-Fri morning

Aloft, a southern-stream long wave trough will extend from western
Mexico east through the Deep South and just offshore the Mid-
Atlantic on Thursday. An associated anomalous upper jet (peaking
into the 99th percentile) will strengthen across the Mid-Altantic
Thursday evening resulting in increasing divergence over the
southeast US.

At the sfc, a strong Arctic high will move across the Ohio Valley
and into the Mid-Atlantic Thursday, extending cold and direr air
into central NC.  The high will initially be favorably placed for
light some wintry precipitation (mostly in the climatologically
favored north of I-85 area) before weakening and progressing
offshore Friday.

Thursday should start off mostly sunny, but considerable cloudiness
and moisture will spread south to north over central NC through
Thursday evening. Temperatures will peak in the lower to mid 50s
Thursday afternoon.

Lift associated with increasing WAA in the mid-levels will generate
a precipitation shield across the TN Valley that will quickly expand
northeast along the southern Appalachians/Foothills/Piedmont through
early Friday morning.  Partial thickness and forecast soundings
continue to suggest that an initial rain/snow mix on the northern
periphery of the shield will likely transition to a period of all
snow for a few hours (primarily along and north of I-85) Friday
morning. Some light accumulations will be possible in this vicinity
before thermal profiles trend above freezing via continued WAA and
amid weakening cold/dry advection from the weakening/transitory sfc
high. During this transition period, some sleet and/or freezing rain
may develop again mostly along and north of I-85. However, without a
persistent feed of cold/dry air, any ice accumulations should be
fairly manageable/negligible.

As we progress through Friday afternoon and evening, a sfc low will
develop along the coastal Carolinas and drive offshore through
Saturday morning. Lift associated with this feature (along with
continued divergence aloft within the exiting jetstreak) will
promote continued light rain primarily along and east of US-1 Friday
night. A few models have hinted at some light freezing rain re-
developing across the NC/VA border Friday night, but think this will
trend drier with time.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
As of 140 PM Wednesday...

* Mixed precipitation event possible Sun night into Mon, but
  synoptic pattern is typically unfavorable for impactful snowfall.

* Bitterly cold temperatures possible Tues morning.

A strong and elongated jet will be in place Sat morning from the
southern Plains through the Mid-Atlantic and into the Atlantic with
150-175kts at 250mb (1-2 SD above normal). On the equatorward side
of the jet, anomalous deep-layer moisture will remain in place with
perturbed H5 flow directed across the Southeast and Mid-Atlantic.
This should favor a continued chance for light rain possible
through Sun. Although the mid-levels should still be cold enough for
ice-crystal formation, lack of saturation above -8C and warming low-
levels will keep all precipitation liquid through Sun.

Forecast uncertainty increases with an added wrinkle of potential p-
type concerns Sun night into Mon. The primary driver in uncertainty
with this next system is the amplitude and propagation speed of the
northern stream wave as it shifts across eastern Canada and the
Northeast. Cluster analysis from the old 00z grand-ensemble suggest
a quicker northern stream wave and shortwave ridging moving across
the Northeast, resulting in a more favorable surface high placement
ahead of the next wave, would provide a greater concern for snowfall
in the Piedmont and northern Coastal Plain. Climatology suggest cold
air arriving `just in time` for the onset of precipitation is
typically not favorable for measurable snow in the Carolinas. This
methodology and leaning on climatology keeps the forecast all rain
for now.

Forecast turns quieter and colder early next week as cold high
pressure on the backside of the Sun night/Mon system filters into
the area and PWAT values drop to well below normal. Tues morning
could be bitterly cold with the surface high centered directly over
the area. Lows in the low/mid 20s to upper teens Tues morning
certainly appear possible.

&&

.AVIATION /00Z THURSDAY THROUGH MONDAY/...
As of 620 PM Wednesday...

24 hour TAF period: There is high confidence in VFR conditions at
INT/GSO/RDU with perhaps a brief round of mid level clouds this
evening, then mostly clear skies through Thursday afternoon. To the
southeast at FAY/RWI, there is the potential for some fog around
daybreak considering the rainfall that occurred during the last 48
hours. However, there is high confidence in a round of 4000 ft
clouds moving over those terminals this evening, and those clouds
could limit the potential for fog to occur from radiational cooling.
Have taken the prevailing MVFR fog and made it a TEMPO group
instead. All sites should have calm conditions or a west-southwest
wind less than 5 kt tonight becoming northwest around 5 kt by
Thursday afternoon.

Outlook: Precipitation will move into INT/GSO late Thursday night
and the remaining terminals Friday morning, bringing IFR/LIFR
conditions to all locations. While FAY will remain all rain, any/all
precipitation types will be possible at the other sites into Friday
afternoon. By Friday afternoon, precipitation should change to all
rain, and at least a slight chance of rain will persist through
Monday.

&&

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

&&

$$

SYNOPSIS...MWS
NEAR TERM...AS
SHORT TERM...Luchetti
LONG TERM...AS
AVIATION...Green