Winston-Salem, North Carolina 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

132
FXUS62 KRAH 171822
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
122 PM EST Sat Jan 17 2026

.WHAT HAS CHANGED...
As of 122 PM Saturday...

* Precipitation amounts tonight through Sun have increased from a
  tenth to three tenths of an inch over the NW/Triad, to one half to
  three quarters of an inch along/east of US-1
* Probabilities for a higher end/worse case snow event of 1-1.5
  inches are low, but have increased slightly in the high-res HREF
  to about 30-40 percent across the northern to northeast Piedmont
  to northern Coastal Plain

&&

.KEY MESSAGES...
As of 122 PM Saturday...

1) A strong mid-level system will move across the region tonight
through early evening Sun, where a band of rain changing to
rain/snow and then snow on the back end will favor a slushy
accumulation of snow over northern and northeast sections of central
NC

2) Cold conditions expected behind a reinforcing Arctic cold front
Monday night and persisting into Wednesday.

&&

.DISCUSSION...
As of 122 PM Saturday...

KEY MESSAGE 1...
A strong mid-level system will move across the region tonight
through early evening Sun, where a band of rain changing to
rain/snow and then snow on the back end will favor a slushy
accumulation of snow over northern and northeast sections of central
NC.

A rather vigorous upper-level shortwave, presently on satellite over
northern TX, will round the base of a larger longwave trough set to
move into much of the eastern US Sun. As the shortwave rounds the
base of the trough over the Carolinas Sun aftn/eve, it will become
negatively tilted before exiting off the Mid-Atlantic coast Sun
night into Mon. An impressive 150-180 kt jet streak will be
positioned from SW to NE from the southern Appalachians into the Mid-
Atlantic, putting central NC in the favored right-entrance region
for enhanced lift at mid/upper levels, primarily from overnight
tonight into early evening Sun.

At the surface, we will see a cold front slowly sag south and east
from the west on Sun, crossing over the mountains and oozing into
eastern sections of the state Sun/Sun night, as an area of low
pressure develops off the coast and tracks off the NE US Sun night.

Precipitation amounts have increased since the last forecast
issuance. This is driven by strong isentropic ascent and some
frontogenesis driven by the jet/shortwave and attendant PW-values
120-130 percent of normal. QPF amounts could range from a a tenth to
three tenths of an inch in the Triad, to one half to three quarters
of along/east of US-1 to the Coastal Plain. Rain should overspread
the region as early as late this evening, but should really get
going after midnight into early Sun morning, when the forcing really
blossoms with the jet. A changeover from rain to rain/snow is
favored for northern areas Sun morning to early Sun afternoon,
becoming briefly all snow in the mid to late afternoon across the
north before exiting early Sun evening.

The main challenge with this system continues to be how fast the
cold air can arrive before the precipitation shield exits early Sun
evening. The other question is whether mesoscale bands within the
precip shield can favor diabatic cooling for a quicker changeover to
snow. If one takes a look at the mesoscale and global models from a
forecast sounding standpoint, there is actual decent agreement on
thermal profiles. Thicknesses would support a narrow 1-3 hour window
when precipitation would changeover to all snow, which is roughly 9a-
12pm in the NW, 1-4pm in the Triangle and points N and NE, and 3p-
6pm in the central/northern Coastal Plain. Little if any snow is
expected in the Sandhills and southern Coastal Plain. Overall,
expected snow amounts have not changed much, with a slushy trace to
half inch or less of snow on mainly elevated/grassy surfaces.

Where could this forecast go off the rails and reach the high
end/worse case amounts of 1-1.5 inches? This scenario could happen
if we see some isolated mesoscale precip bands that enhance diabatic
cooling of the column. There could also be a narrow 1-3 hr window
when mid-level lift/fgen could coincide with saturation in the
dendritic growth zone to favor a narrow zone of heavier snow rates
and support this higher worse case scenario. If this were to occur,
it would roughly be from just east of Burlington to Roxboro to NE of
Raleigh to Henderson to Roanoke Rapids, where HREF/LREF snow
probabilities for this worse case are highest. Confidence in this
scenario remains low but HREF probabilities for 1-1.5 inches do show
30-40 percent values in this region, a little higher than the global
LREF of 15-percent. For now, will continue to message the most
favored outcome noted earlier.

Precipitation wraps up early Sun evening and temperatures fall into
the 20s overnight into Mon, which may result in some refreezing and
icy patches on roadways Sun night to Mon morning.


KEY MESSAGE 2...
Cold conditions expected behind a reinforcing Arctic cold front
Monday night and persisting into Wednesday.

Highly amplified mid/upper level flow is expected across the CONUS
by Mon morning, potentially record breaking >580dam H5 ridge over
the eastern Pacific off the British Columbia coast and deep/broad
troughing over the central/eastern NOAM. In between these upper
level features, strong surface high pressure will ooze down the
eastern Rockies into the northern/central Plains before settling
over the Southeast and Mid-Atlantic by Wed morning.

After some modification of the Arctic air mass in place on Mon
within the southwesterly winds, CAA behind the fropa Mon evening
will return temperatures to well-below normal Mon night, Tues, and
Wed morning when highs/lows will be 10-15 degrees below normal. The
coldest air temperatures will likely occur Wed morning due to the
optimal radiational cooling setup. Apparent temperatures are not
expected to reach Cold Weather Advisory criteria, but hypothermia
could still occur with any prolonged exposure and lack of proper
clothing.

&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
As of 122 PM Saturday...

TAF period: INT/GSO currently have MVFR ceilings which should lift
as clearing occurs this afternoon. VFR cloud cover should persist
through the afternoon at RDU/RWI/FAY, with the possibility of MVFR
ceilings at RDU. Several hours of VFR conditions are expected at all
terminals this evening into the overnight hours, but restrictions
will develop once again as precipitation moves back into the region.
Rain will be the dominate precipitation type, although snow could
mix in at INT, GSO, and RDU. It appears that INT/GSO will likely
remain MVFR tonight into Sunday morning, although there is high
confidence that RDU/RWI/FAY will all drop to IFR ceilings, if not
LIFR ceilings. The wind will be out of the southwest this afternoon,
with gusts up to 20 kt at FAY/RWI, veering to the northwest after
midnight as precipitation begins.

Outlook: Widespread restrictions will continue Sunday afternoon as
precipitation moves to the east, but dry VFR conditions should
return by Sunday evening. The dry VFR conditions should continue
through Thursday, when a slight chance of rain will return to the
forecast. There could be gusts out of the west as high as 20 kt on
Monday.

&&

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

&&

$$

DISCUSSION...Kren/Swiggett
AVIATION...Green