Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC
FXUS62 KRAH 260745
Area Forecast Discussion
National Weather Service Raleigh NC
305 AM EDT MON SEP 26 2016
A quasi-stationary front across southwestern NC will return north as a
warm front tonight as a cold front approaches from the west. The cold front
will move very slowly southeast through the area Tuesday and into Wednesday.
.NEAR TERM /OVERNIGHT/...
As of 905 PM Sunday...
A band of moisture in the lowest 8k ft of the atmosphere underneath
a mid/upper level ridge will result in a deck of low clouds over
most of central NC overnight. The exception will be the far southern-
southwest sections where skies may remain partly cloudy.
Most of the convective allowing models as well as successive runs of
the HRRR suggest scattered showers in vicinity of the Triad late
this evening into the overnight hours. Based on current moisture
profile and upper air analysis, moisture appears too shallow and
synoptic lift virtually non-existent to suggest anything more than a
slight chance PoP for the western counties through the night. May
see pockets of fog over the western and southern counties though
dense fog not anticipated at this time.
Overnight temps will vary from the upper 60s over the southwest to
near 60/lower 60s over the northeast.
.SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...
As of 245 PM Sunday...
Monday will be a murky day as hybrid CAD is expected to develop over
the western Piedmont as a warm/moist advection pattern sets up
between the surface and 850 mb. This occurs as the low level ridge
axis begins to shift east and the next cold front approaches the
Appalachians from the west. Expect the moisture profile further
increase though the day, except for the far eastern zones were some
drying will linger with the ridging. As a mid level trough and the
cold front approach the mountains late, the associated lift and
upslope easterly flow generate areas of rain. This will aid in
locking in the hybrid CAD over the damming region. This pattern will
persist overnight with rain likely in the west, spreading east into
the rest of central NC overnight. We will cap of POP in the high
chance category in the SE Coastal Plain through 12Z/Tue as they will
be farther away from the approaching trough and cold front through
then. Highs Monday from the lower 70s NW to mid 80s south. Lows
Monday night 65-70. QPF of 0.25 to 0.50 forecast for the NW with
less than 0.10 in the SE through 12Z/Tue.
.LONG TERM /Wednesday through Sunday/...
As of 345 AM Monday...
Forecast confidence remains below average due to an atypically
complex synoptic pattern expected to evolve over North America
mid/late week. The 00Z GFS/ECMWF both indicate that an upper level
low amplifying over the Great Lakes early this week will dig
southward through the OH valley and cut-off in vicinity of the TN
Valley/Mid-Atlantic through mid/late week as an expansive upper
level ridge builds over the eastern 2/3 of North America, though
disagreement persists w/regard to the precise evolution of the cut-
off low. Broadly speaking, long range guidance supports above normal
chances for cloud cover/precipitation and slightly below normal
temperatures mid/late week, though further details (i.e. precip
amount/timing and perhaps severe wx potential) remain difficult to
ascertain at this time. -Vincent
.AVIATION /06Z MONDAY THROUGH THURSDAY/...
As of 115 AM Monday...
IFR to MVFR ceilings are expected overnight, lowest at KINT and KGSO
in closer proximity to a a quasi-stationary frontal boundary that
extends across the western/southern piedmont. Additionally, sely
moist upglide atop a quasi-stationary frontal boundary will support
a small chance of showers over the TRIAD overnight and into the
Any sub-VFR conditions in the east(KRWI and KFAY) should become VFR
by 14 to 15z, with KRDU expected to become VFR between 15 to 18z.
Ceilings will be much slower to improve at KGSO and KINT, with
MVFR or low end VFR lingering into the afternoon 18 to 21z time
frame. Moisture pooling ahead of a cold front moving into the
mountains will also support a small chance of showers and possibly
a thunderstorm late in the afternoon/early evening with rain chances
increasing overnight with sub-VFR ceilings as the front approaches
the NW Piedmont.
Looking beyond the 24 TAF Period: A cold front will move very slowly
se through the area Tuesday and into the day on Wednesday. Showers
and storms with associated periods of sub-VFR conditions are
expected to accompany the front. Conditions are expected to improve
to VFR from northwest to southeast Wednesday-Wednesday night as
drier air filters into the area.
During midweek, a rather unsettled pattern is expected to evolve as
a deep upper low sags southward from the Great Lakes into the