Scientific Forecaster Discussion
fxus62 krah 251745
Area forecast discussion
National Weather Service Raleigh NC
145 PM EDT sun Jun 25 2017
a cold front will push southeastward through central North Carolina,
weakening as it pushes to the coast later today. A second cold front
will sweep through the area on Tuesday, followed by high pressure
that will persist across the region through the rest of the
Near term /this afternoon and tonight/...
as of 1030 am EDT Sunday...
Main adjustment to the near term forecast was to adjust dewpoints
upward several degrees as drier air not advecting into central NC as
quickly as earlier thinking.
12z sfc and upper air analysis depict a low level trough and
attendant sfc front crossing central NC. Sf dewpoints have lowered
into the low-mid 60s across the NW Piedmont while dewpoints in the
low-mid 70s still apparent across the remainder of the region. While
the sfc front will exit our far eastern-southeast counties by early
afternoon, not until the passage of the 850mb trough around/after
18z will most of central NC start to see the dewpoints lower. West-
southwest flow aloft will continue to stream high level moisture
overhead, so even though the lower layers of the atmosphere will dry
out, high level cloudiness will still be evident. Thus expect skies
to be variably cloudy/partly sunny this afternoon. Temperatures o
track to reach the mid-upper 80s with places across the sandhills
and southern coastal plain reaching 90.
Isolated convection still probable along our eastern-se periphery
through late afternoon. Elsewhere a stable drier air mass should
inhibit convective development.
Tonight, west-NW flow will continue to usher in the drier air mass.
Thus it should be noticeably less humid. Skies will slowly clear,
with mostly clear skies regionwide by the overnight hours. Min temps
quite pleasant for early Summer, ranging from the upper 50s to
around 60 in the NW Piedmont to the mid 60s southeast.
A cold front stretches along the eastern fringe of the Piedmont
early this morning, accompanied by a few weakening showers. This
front will slow as it approaches the coast early this afternoon,
resulting in a small chance of showers in the southern coastal plain
and sandhills through late day. Northwest flow behind the front will
lead to a more stable airmass settling north of the front, but
cooler air will be delayed until tonight, so highs today will reach
the mid to upper 80s. Tonight, as skies clear with the drier airmass
in place, temperatures will fall to the upper 50s in the northwest
to mid 60s in the southeast.
Short term /Monday and Monday night/...
as of 345 am EDT Sunday...
Modestly cooler and drier air will be in place on Monday, making for
a pleasant day with mostly sunny skies and highs topping out in the
low to mid 80s. A dry, reinforcing cold front will dip southeast and
through the area Monday night as a long wave trof over the northeast
Continental U.S. Amplifies. Continued cool air advection and good radiational
conditions will allow mins to bottom out in the upper 50s to low
60s Tuesday morning.
Long term /Tuesday through Sunday/...
as of 145 PM Sunday...
A cooler airmass settles over the region Tuesday into Wednesday as
the trough axis traverses the area. Latest model guidance continues
to suggest that a broken line of showers and tstms may move across
central NC Tuesday afternoon as the trough axis approaches and moves
through. Wednesday will be rain free and little if any clouds.
High pressure at the surface will move east of the region Thursday
and Friday. Rain chances will be very low but temperatures and dew
points will trend upward as a south to southwesterly low level flow
resumes across the Carolinas.
Southerly flow will further increase over the weekend in response to
a short wave moving across the Great Lakes region and a surface
front approaching the Appalachians. Rain chances will increase
Saturday and Sunday as low level moisture and synoptic scale forcing
Aviation /18z Sunday through Friday/...
as of 115 PM Sunday...
VFR parameters expected across central NC through Monday night.
A surface cold front will drift southeastward and exit central NC
prior to sunset. West-northwest flow behind the exiting boundary
will usher a drier and more stable air mass into the region. The
arrival of this drier air mass will lead to decreasing cloudiness,
particularly of the low level variety. A few sprinkles or light rain
showers will occur through the evening hours as a weak upper
disturbance passes overhead.
VFR conditions anticipated Monday night through Friday. A few light
rain showers and possibly brief instances of MVFR parameters may
occur Tuesday as another upper disturbance and attendant surface
cold front crosses overhead.