Area Forecast Discussion
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FXUS62 KRAH 071449
Area Forecast Discussion
National Weather Service Raleigh NC
940 AM EST Wed Dec 7 2016
Weak high pressure will settle over the Carolinas today.
An arctic cold front will move through the area Thursday.
.NEAR TERM /THROUGH TONIGHT/...
As of 940 AM Wednesday...
Mostly clear skies across central NC this morning, except for in the
southern Piedmont where fog has been slow to disperse, though
visible satellite imagery is finally showing signs of improvement.
High pressure will settle over the area today between a low
departing tot he northeast and an arctic cold front moving through
the Midwest. Skies will remain clear for most of the day in most
areas, but some of the low-level moisture in the Coastal Plain may
result in scattered cur this afternoon, while abundant moisture over
SC will inevitably return north across the western Piedmont this
evening as the flow veers to southerly ahead of the cold front. None
of this will have an impact on afternoon highs, which MAV/MET MOS
suggest will be in the mid to upper 50s in relatively hallow mixing
below the subsidence inversion. -BS
Tonight...Models have been pretty consistent in showing some
isolated showers/sprinkles accompanying the front, with the front
expected to approach the Triad right around daybreak Thursday.
Uniform lows in the upper 30s to lower 40s.
.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
As of 320 AM Wednesday...
Shallow moist upglide ahead of the leading edge of the Arctic
intrusion spreading west to east through the area on Thursday will
support a broken band of very light rain showers/or sprinkles with
abrupt clearing in it`s wake owing to the strong cold dry air
advection. In fact, we could see temperatures falling across the
western piedmont by the afternoon. Highs ranging from lower 50s NW
to upper 50s southeast.
Strong CAA will continue Thursday as expansive Arctic high begins
east into the region. Overnight lows in the mid 20s to upper 20s
with a steady wind 7kt breeze resulting in chill values in the teens.
.LONG TERM /FRIDAY THROUGH TUESDAY/...
As of 205 AM Wednesday...
Expect cold/brisk conditions on Friday with highs in the upper 30s
to lower 40s and a brisk NW breeze assoc/w strong cold advection as
1040 mb arctic high pressure builds eastward from the central plains
toward the Appalachians in the wake of the cold frontal passage late
Thu/Thu night. Expect chilly lows in the upper teens to lower 20s
Sat morning as the arctic high settles over the Carolinas from the
west Friday night, with highs on Sat similar to Friday albeit a few
degrees warmer. Forecast confidence decreases significantly in the
Sun-Tue time frame when the GFS/ECMWF differ by as much as ~24 hours
with regard to the timing/evolution of the next upper wave/cold
front approaching from the west. The GFS indicates a weaker, more
progressive wave with an attendant cold front moving offshore Sun
night. The ECMWF, however, indicates a more potent upper level wave
/attendant sfc low/ and suggests the associated cold front will
cross central NC Monday afternoon, exiting offshore late Monday
evening into Monday night. With the above uncertainty in mind, will
make little change to the prior forecast Sun-Tue. -Vincent
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
As of 0630 AM WEDNESDAY...
Drier air will continue to filter into the area from the west,
leading to scattering out any lingering IFR ceilings and fog
across this morning with VFR conditions expected to be the rule
through the afternoon.
Outlook: Shallow warm-moist air advection in advance of a strong
arctic cold front will result in a good chance of MVFR ceilings
within a broken band of isolated showers that will move west to east
the area on Thursday.