Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Raleigh NC
230 PM EDT Sat Aug 30 2014
Synopsis...high pressure will build aloft over the region through
Near term /through tonight/...
as of 230 PM Saturday...
High pressure both aloft and at the surface remain over the
region...although the surface high will continue to shift east...
allowing a moist southerly flow to return to the area. The sea
breeze has become fairly active this afternoon as it moves inland.
This will result in the best chance of precipitation occurring across the
eastern portions of the forecast area...although a isolated
shower/storm or two will certainly be possible further to the west.
Most of the activity should dissipate with the loss of daytime
heating and overnight lows are expected to fall to within a few
degrees of 70. Patchy fog and/or stratus will be possible again
tonight as the near surface moisture content remains high.
Short term /Sunday and Sunday night/...
as of 230 PM Saturday...
A short wave trough over the MS River Valley to start the day will
lift to the northeast into the Ohio Valley through Sunday night.
However...its associated energy and deep moisture plume (emanating
from the gulf) will largely remain west and north of central NC. In
addition...the subtropical ridge centered over the southeast coast
should also help keep the better rain chances west of the area.
Therefore...will continue the forecast thinking of only isolated to
widely scattered showers/storms...with the best chances across the
west due to the proximity of the above features. Temperatures will continue
to be above normal...with highs generally in the lower 90s and
overnight lows around 70 degrees.
Long term /Monday through Saturday/...
as of 200 PM Saturday...
With roughly 3 weeks of Summer remaining (autumn equinox is sept
23)...the westward expansion of the subtropical ridge across much of
the southern Continental U.S....with the main belt of westerlies retreating
northward along the US-Canada border will result in the first
prolonged period of summertime heat and convective rain chances that
central NC has seen this season. Afternoon thicknesses are prognosticated
to run 25 to 30 meters above climatology...which should support
daytime highs ranging from 90 to 95f with lows in the upper 68 to
A low amplitude trough moving eastward across the northeast and Middle-
Atlantic States will temporarily flatten the upper anticyclone long
enough to allow a weak surface front to approach NC from the
north...but recent model trends over the last couple of days really
washes out the front to our north during the late Wednesday/Thursday
period. As such...gridded database will continue to exhibit
diurnally driven convection isolated to widely scattered storms each
afternoon...firing within a moderately unstable airmass along a Lee
side surface trough.
Aviation /18z Saturday through Thursday/...
as of 130 PM Saturday...
VFR conditions have returned to the area as the low clouds lifted
into a 4-5 kft cloud deck. A few isolated showers/storms will be
possible this afternoon associated with the inland moving sea-breeze.
Thus the best chances will be across the east...but have not
included any mention in the tafs for now as there is low confidence
with respect to exact timing/location (although kfay may have the
best chance). Then...once again patchy fog/low stratus will be
possible tonight into early Sunday morning.
Outlook...a summertime pattern will persist through early/middle next
week...with isolated to scattered afternoon/evening convection and a
potential for early morning fog/stratus.