Area Forecast Discussion
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FXUS62 KRAH 160548
Area Forecast Discussion
National Weather Service Raleigh NC
1248 AM EST Mon Jan 16 2017
High pressure to the northeast will set up cold air damming over
central NC through Monday before a low pressure system approaches
the area midweek.
.NEAR TERM /THROUGH TONIGHT/...
As of 928 PM Sunday...
A 1030 MB surface high over the northern Mid-Atlantic States will
build southward into the area overnight. 925-850mb southerly upglide
atop the cooler airmass advecting into the region from the NE has
and will continue to support patchy light rain overnight, eventually
waning Monday morning. Precipitation will be vary light with mostly
The isentropic lift will aid to initiate another cold air damming
episode overnight. Min temps should vary from near 40 northeast
to mid 40s southwest.
.SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...
As of 310 PM Sunday...
Monday, ongoing CAD atop a quasi-stationary frontal zone extending
across upstate SC and back into southwestern NC will maintain a low
overcast deck through the morning, with patchy light rain and/or
drizzle possible across the northern counties. Temperatures will be
slow to recover, especially across the north half. An end to the
spotty light precip and a gradually lifting of the ceilings will
allow temps to rebound into the lower 50s across the south and the
mid-upper 40s across the north. If ceilings lift sooner or
dissipate, potential for afternoon temperatures to be 5-6 degrees
warmer, primarily across the south.
Monday night, expect variable cloudy skies to persist while another
weak perturbation will approach from the west. This feature may
trigger a patch or two of light rain and/or drizzle, mainly over the
western Piedmont. Min temps in the low-mid 40s.
.LONG TERM /TUESDAY THROUGH SUNDAY/...
As of 220 PM Sunday...
Models continue to come into better agreement with the overall
pattern through Friday. There are still small timing issues and
differences in precip chances/timing over central NC. Generally,
expect multiple rounds of wet weather with dry periods in between.
Timing and amounts are still a challenge. The weather could get very
interesting for late next weekend and early the following week.
Tuesday through Wednesday Night: The wedge will probably linger
through early Tuesday, however the models erode it by the aft/eve as
the return flow from the high offshore and the southerly flow ahead
of the approaching front both increase. Meanwhile aloft, the
remnants of a closed low over the Baja gets absorbed into the
northern stream as a shortwave that swings through the Great Lakes
through and into the Mid-Atlantic Wednesday/Wednesday night. The
wave should be strong enough to dampen/suppress the ridge. The
surface low and attendant front will approach the area Tuesday
night, swinging through by late aft/eve Wednesday. As a result,
expect best chances for rain to be late Tuesday through Wednesday
from west to east. Temperatures will be above normal, slightly cooler
in the NW Tuesday (mid to upper 50s), but otherwise expect highs in
the 60s and lows in the mid 50s Tuesday night. With the expected
frontal passage late Wednesday, overnight lows will be lower, mid
40s north to around 50 degrees south.
Thursday through Friday Night: There is surprising agreement between
the models for this period, though there are some differences, the
pattern is similar. Expect two additional rounds of precipitation
during this time, with a period of dry weather in between. A fleeting
surface high and upper level ridge will move through/build over the
area Thursday while another low moves out of the desert southwest
northeast toward the Great Lakes. The moisture advection into the
Gulf coast states Thursday night combined with the sufficient
forcing from the low will result in another round of rain moving
into the Carolinas from the southwest Friday/Friday Night.
Temperatures should be fairly steady during this time, highs in the
upper 50s to mid 60s and lows in the 40s.
Saturday and Sunday: This part of the forecast period gets quite
interesting and the model agreement make it even more ominous.
Although, this far out it is hard to jump on board completely.
Fingers crossed for some changes. As of the latest model runs, a
strong low will come onshore in the Pacific NW Friday/Friday night
digging a trough south and east toward TX Saturday and Sunday. In
the wake of the low that moves through Central NC Friday night, a
ridge builds aloft over the southeast U.S. while the surface low
strengthens over the Midwest. Very strong southerly flow advects
very warm moist air into the Gulf Coast states late in the weekend.
There is a bit of uncertainty whether a CAD wedge will set up and
hold over NC or not and thus temperatures are low confidence, but do
expect increasing chances for rain late Sunday into early in the
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
AS OF 1244 AM Monday...
24 Hour TAF period: MVFR ceilings beginning to show up across the
CWA this morning and conditions are expected to continue to
deteriorate with IFR conditions if not LIFR ceilings to begin to
show up at least at the Triad sites if not all as in-situ cold air
damming begins to set in across the NW Piedmont. expect light winds
out of the northeast or east through the period. Ceilings are not
expected to lift beyond MVFR levels in most locations on Monday with
the exception of KRWI and possibly KFAY late in the day. Otherwise
will maintain MVFR conditions through the end of the TAF period.
Some light rain will also be possible.
Long term: An active pattern will see several systems cross the area
next week. While no winter precipitation is expected, adverse
aviation conditions due to low ceilings and visibilities are