Scientific Forecaster Discussion
fxus62 krah 280112
Area forecast discussion
National Weather Service Raleigh NC
912 PM EDT Tue Jun 27 2017
a moisture-starved cold front will exit central NC this evening.
Canadian high pressure will follow and extend over the Carolinas and
southern Virginia Wednesday and Wednesday night.
Near term /through tonight/...
as of 912 PM EDT Tuesday...
Strong subsidence in the wave of the exiting shortwave trough
pushing east of the area is leading to abrupt clearing this evening.
Thereafter, Canadian high pressure will build into the region
advecting cooler and drier air into the Carolinas. This drier cooler
air mass and a near calm sfc regime at the surface will allow for
very pleasant/comfortable conditions with overnight lows cooling
into the 50s overnight across the Piedmont, and near 60-lower 60s
across the sandhills and southern coastal plain. Enjoy, this may the
last sub 60 degree readings for quite some time!
Short term /Wednesday and Wednesday night/...
as of 310 PM EDT Tuesday...
An area of high pressure at the surface coupled with rising heights
aloft translates to dry and pleasant conditions for Wednesday and
Wednesday night. The sfc high will deposit a dry air mass over
central NC, maintaining dewpoints int the 50s. After the seasonably
cool start, afternoon temperatures will rebound into the low-mid
The center of the high will drift offshore by early Thursday
evening, initiating a return sly flow across the NC Piedmont. Thus,
dewpoints will start to inch upward indicative of the return of low
level moisture. Still, under mostly clear skies, overnight
temperatures will remain comfortable for this time of year,
generally near 60-lower 60s.
Long term /Thursday through Tuesday/...
as of 300 PM EDT Tuesday...
A subtle upper level low in vicinity of the Texas Gulf Coast this
afternoon is progged to meander slowly NE into the deep south on Thu
before deamplifying/lifting NE across portions of the Carolinas on
Fri. Expect dry conditions to persist on Thu, followed by an
increasing potential for convection Fri afternoon/evening as the
deamplifying upper wave lifts NE across the Carolinas and southerly
return flow strengthens (temps/moisture rebound toward climatology).
Cyclonic flow aloft will strengthen over the eastern US this weekend
as a potent upper level low (currently in alberta) digs southeast into the
Great Lakes (sat) and lifts NE across New England (sun). Broad
troughing aloft will suppress/confine the sub-tropical ridge to the
Florida Peninsula and aid in the development/maintenance of a pronounced
surface trough east of the Appalachians over the weekend. With the
above in mind, expect above normal chances for convection and near
normal temperatures Sat/sun. Forecast confidence decreases early
next week. Several mcs's are expected to develop upstream of the
region Mon/Tue as shortwave energy in northwest flow aloft progresses from
The Rockies into the Central Plains/central MS River Valley. In
general, temperatures are expected to increase as flow aloft over
the mid-Atlantic weakens/flattens and the previously suppressed sub-
tropical ridge expands northward from Florida into the deep south/
southeast, and the relative best potential for convection should
shift along/east of the Hwy 1 corridor, though coverage/timing may
ultimately depend on the evolution of upstream mcs's. -Vincent
Aviation /00z Wednesday through Sunday/...
as of 740 PM EDT Tuesday...
24 hour taf period: VFR conditions are expected to continue through
the 24 hour taf period as surface high pressure builds into and
across the region. This will generally result in light and variable
winds and mostly clear skies.
Outlook: VFR conditions are expected to continue through Thursday
evening. A moistening southerly return flow will allow for the
chance of early-mid morning sub-VFR conditions from Friday morning
on, with an increase in mostly diurnal showers and storms from
Friday afternoon Onward.