Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
FXUS62 KRAH 241840
Area Forecast Discussion
National Weather Service Raleigh NC
240 PM EDT WED AUG 24 2016
.SYNOPSIS...High pressure will extend across the region through the
rest of the week, with slowly rising temperatures and humidity.
.NEAR TERM /THROUGH TONIGHT/...
As of 1045 AM Wednesday...
Little change required to the near term forecast.
An area of high pressure extending across central NC will result in
hot and dry conditions this afternoon. A thin layer of moisture
trapped below a mid level subsidence inversion will result in
patches of mid level cloudiness at times. Subsidence and a
relatively dry air mass aloft will inhibit convective development
across most of the area. The exception will be in vicinity of the
Yadkin River valley where a stray shower or storm may develop in a
narrow zone of low level moisture convergence. Afternoon temps in
the upper 80s to around 90 appear on track.
Tonight, overnight temps will cool back into the 60s under mostly
clear/partly cloudy skies as the area of high pressure maintains
control of our weather.
.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
As of 145 AM Wednesday...
The surface ridge axis will push offshore leading to a WSW flow
aiding warming as the mid level ridging strengthens over the
southern Appalachians. Continued mainly sunny, dry, and becoming hot
Thursday. Highs in the upper 80s to mid 90s N to S. Lows in the
upper 60s to lower 70s.
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
As of 240 PM Wednesday...
Fri-Sun: Quite warm to start this period, followed by moderating
temps, and very low precip chances throughout. Strong mid level
ridging will remain the dominant weather feature heading into the
weekend, with its center drifting slowly from the western Carolinas
early Fri ENE to over eastern VA/NE NC by Sun, all the while
maintaining dry and stable mid-upper levels over our area. A surface
cold front approaching from the NW Fri will drop into and through NC
over the weekend, causing a dip in thicknesses from much above
normal Fri/Sat to near or just slightly above normal starting Sun.
With a weakening low level wind field and no opportunity for
moisture influx at any level, any convection ahead of or with the
front will be feeble and very isolated, likely limited to a few
cells drifting slowly off the higher terrain (extreme NW CWA) and
along an inland-drifting sea breeze (far SE CWA) late in the day
Fri, with perhaps a bit better (but still low) coverage Sat
afternoon over the southwest CWA near weak upglide and low level
mass convergence near the Piedmont trough. The front settles to our
south Sun with a high pressure ridge centered off New England nosing
narrowly to the SW through central NC, supporting a drop in max
temps from the mid 90s Fri/Sat to around 90 or the lower 90s
Mon-Wed: Starting Mon, the mid level ridge weakens and flattens yet
continues to extend W-E across the region. Low level flow from the
east or ENE may be sufficiently strong and onshore-directed to boost
low level moisture profiles and increase diurnal sea-breeze
convection chances in the SE CWA on Mon, although the limited deep
moisture should keep coverage low. Models still vary quite a bit
with the tropical wave now over the northern Leeward Islands which
may be driven toward the WNW by the mid level ridge and may affect a
portion of FL and/or the Gulf Coast by early to mid week. Model
solutions continue to range widely, with the GFS remaining weak with
an erratic motion and the so-far-strongest ECMWF solution showing a
slowing trend with the 12z/24 run, which all results in reduced
confidence in any details this far out. At the very least, the
increasing easterly low-mid level component should draw increasing
amounts of Atlantic moisture into the eastern Carolinas, and we
should see an increase in daily showers and a few storms mainly east
as we head into midweek. We will, of course, continue to monitor the
tropical wave, although by all accounts it will not be a direct
factor in our weather through at least Wed. With thicknesses holding
a bit above normal, temps are expected to peak around 90 to the
lower 90s Mon-Wed, with lows mostly in the lower 70s. -GIH
.AVIATION /18Z WEDNESDAY THROUGH THURSDAY/...
As of 120 PM Wednesday...
There is a high probability that VFR conditions will persist across
central NC through Thursday night. The exception will be pockets
of MVFR/IFR visibility between 09Z-12Z, mainly in the sandhills and
coastal plain. This possibility appears highest in vicinity of KRWI.
Otherwise, an area of high pressure will maintain dry weather with
light wind conditions.
This area of high pressure is expected to maintain its influence over
our region through early next week. This suggest an extended period
of VFR conditions, aside from patchy early morning MVFR/IFR fog or