Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC-- Remove Highlighting --
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FXUS62 KRAH 130146
Area Forecast Discussion
National Weather Service Raleigh NC
845 PM EST Thu Jan 12 2017
High pressure over the western Atlantic will extend westward across
the Southeast U.S. through Friday. A cold front will enter the state
from the north late Friday, and push through central NC Friday night.
.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --As of 845 PM Thursday...
Mild light low level flow from the S/SW will persist tonight ahead
of a cold front stretching from New England through the Ohio Valley
to AR/N TX. 00z soundings in the area and upstream are fairly dry,
except for shallow near-ground moisture resulting from nocturnal
cooling with high dewpoints, and well as some high thin clouds
across the north, riding atop the mid level ridge over the
Southeast/FL. Expect dry weather and largely partly cloudy skies
overnight. Current very mild temps are on pace to reach lows in the
upper 40s to lower 50s, close to the normal highs for this time of
Previous discussion from 255 PM Thursday: Breezy sw sfc winds and
partly sunny skies have pumped afternoon temperatures into the
spring-like upper 60s and lower 70s. Wind gusts have been
sporadically strong with a gust of 37 mph recorded at the Halifax
County airport earlier this afternoon.
Under partly cloudy skies and a steady sly sfc wind tonight, expect
mild conditions for January. Overnight temperatures will only dip
into the upper 40s-lower 50s, comparable to normal daytime highs for
this time of year. Could still see pockets or areas of fog late
tonight, mainly across the north half, though a steady sly sfc winds
should keep the atmosphere just mixed enough to prevent the fog from
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.SHORT TERM /FRIDAY AND FRIDAY NIGHT/...
AS OF 255 PM Thursday...
A strong cold front, being driven by a series of perturbations in
the northern stream, will lie west-to-east across southern Virginia
early Friday morning. This boundary will drift southward as an
arctic high moves from the northern Plains into the Great Lakes.
The front should cross into our far northern-ne counties early
Friday afternoon, likely reaching the Triangle area by mid-late
afternoon. This suggest that high temperatures for the day across
our far northern-northeast sections may occur prior to 2 PM, with
falling temperatures in the afternoon. Elsewhere, warm sly flow will
persist, aiding to push temperatures back into the upper 60s-lower
70s with the warmest temperatures across the south-southeast. Not
much in the manner of convergence along this boundary so expect
little if any precipitation along or ahead of the front.
The front will continue to settle southward Friday night, exiting
our southern counties late Friday evening. While the near sfc flow
will veer to a north-ne direction behind the front, winds aloft will
remain swly or wly. This overrunning set-up will cause a deck of low
clouds to develop and eventually lead to patchy light rain, mainly
over the Piedmont, Friday night. Isentropic upglide not overly
impressive, suggesting that the precipitation will be spotty and
light in nature. For now will indicate solid chance PoPs in vicinity
of our far western-northwest periphery Friday night.
Northeast low level flow will advect a much colder air mass into
central NC Friday night, driving overnight temperatures into the
upper 30s and lower 40s. When the wind is factored in, wind chill
values by early Saturday will be near or below freezing across the
northern half of central NC.
.LONG TERM /SATURDAY THROUGH THURSDAY/...
As of 200 PM Thursday...
The upper level high over FL, will weaken Saturday and upper level
flow over NC will become more west-northwesterly. At the surface, a
CAD wedge will set up in the wake of a backdoor cold front on
Saturday. The models have backed off on chances for rain to fall
into the wedge airmass and subsequently erode it quicker than
previous runs. With the wedge in place, expect temperatures much
lower than previous days, highs around 40 degrees north to near 50
degrees south on Saturday and lows in the low 40s overnight. Weak
disturbances in the west-northwest flow aloft may result in some
light rain/drizzle across the north, mainly along the NC/VA border
Sunday and Sunday night, elsewhere should remain dry. Do not expect
any p-type issues or significant rainfall accumulations at this
time. Some additional weak ridging of the high southward into
western NC is possible again Sunday night (if the wedge completely
erodes before that) before the parent high lifts away to the
northeast on Monday. As a result, lows Sunday night will be similar
to the previous night, low to mid 40s, despite some moderation in
From Monday night onward, expect moderating temperatures with lows
in the mid 50s and highs in the low to mid 60s by Wednesday night
and Thursday. Expect the weather on Monday and Tuesday to remain
dry. The upper level ridge will build back over the southeast U.S.
Monday and the flow aloft will become increasingly more meridional
through mid-week. The resultant increase in south-southwest flow
between the aforementioned ridge and the low moving across the
Midwest will increase moisture advection ahead of the front and thus
increase rain chances from west to east Wednesday and Thursday. The
best rain chances are expected to be on Thursday ahead of the
approaching cold front.
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
AS OF 800 PM Thursday...
24 Hour TAF period: VFR conditions across the area this evening with
a much drier airmass across the area. Short term models are
indicating a drop in visibilities, with the most likely spot to go
down to MVFR/IFR levels being the Triad sites. Other terminals
across central NC should have only scattered clouds and maybe MVFR
ceilings but most likely no lower. If sites go down to MVFR/IFR
levels, and confidence in this is low.
Long term: A frontal zone over the area during the weekend could
lead to adverse aviation conditions. Through the weekend. A moist
air mass will also lead to the possibility of fog and low stratus
for the next several nights.