Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC-- Highlight Changed Discussion --
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FXUS62 KRAH 240159
Area Forecast Discussion
National Weather Service Raleigh NC
959 PM EDT TUE AUG 23 2016
.SYNOPSIS... High pressure will extend across the region through
the week. Temperatures and humidities will gradually rise through
.NEAR TERM /TONIGHT/...
-- Changed Discussion --As of 955 PM Tuesday...
Modified cP, 1026 mb surface high pressure centered over NJ will
continue to extend across central NC tonight, with associated calm
to infrequent light ELY stirring. Regional RAOB data suggests there
is a very thin layer of moisture trapped at the base of a strong
subsidence inversion around 7-8 thousand ft, which will support the
occasional bubbling of altocumulus, beneath passing cirrus in NW
flow around an upper ridge analyzed over the along the ERN Gulf
coast. Associated sky conditions will average partly cloudy to
mostly clear. Projected low level thickness values around 1390-1400
meters favor persistence low temperatures mostly in the lower to
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.SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/...
As of 200 PM Tuesday...
Wednesday will be a near carbon copy to today as Subtropical ridging
remains firmly in control in the upper levels, with dry air
surface ridge hanging on, albeit in a weakening state.
This will ensure dry weather with seasonable daytime highs once
again in the mid 80s northwest to around 90 southeast. Mostly clear
Wednesday night with lows in the 60s.
.LONG TERM /THURSDAY THROUGH TUESDAY/...
As of 305 PM Tuesday...
This looks to be a fairly tranquil period with very low precip
chances. Strong mid level ridging will remain the dominant weather
feature, centered over the Mid South and Deep South early Thu, with
its center drifting slowly to the ENE over the western Carolinas by
Fri morning, to over VA and northern NC early Sat, where it will
hold through at least Mon, maintaining dry and stable mid-upper
levels over our area. The narrow surface ridge centered well to our
NE and extending southwestward across central NC early Thu will
weaken further with its axis pushing to our SE as a cold front
approaches from the NW through Fri. Thicknesses will respond by
rebounding from near-normal readings early Thu to 10-20 m above
normal Fri into Sat. The front will drop into and through NC over
the weekend, however with a weakening low level wind field and no
opportunity for moisture influx at any level, any convection will be
feeble and very isolated, limited to a few cells drifting off the
higher terrain (likely a slow and difficult trip given the low
speeds of the steering flow) and along an inland-drifting sea breeze
late in the day Sat and Sun. New surface ridging attempts to build
in from the north late Sun into Mon as it drifts eastward off the
Canadian Maritime coast, however thicknesses dip minimally and
remain just above normal through the early part of next work week.
Forecast uncertainty starts to rise Tue with the weakening surface
ridge axis shifting to our east and another frontal zone approaching
from the WNW. A couple of modeling systems suggest that the evolving
system now east of the Lesser Antilles may be driven toward the WNW
by the Carolinas anticyclone and may affect a portion of FL, the
Gulf Coast, or Southeast states by Mon or Tue. Model agreement on
this is not ideal, however, reducing forecast confidence, but we`ll
continue to monitor. Highs around 90 Thu will trend to the mid 90s
for Fri/Sat, then dip back into the lower 90s for Sun-Tue. Lows will
be around 70 trending to the lower 70s. -GIH
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
As of 810 PM Tuesday...
24 Hour TAF Period: There is a high confidence of VFR conditions
continuing through the 24 hour TAF period with high pressure in
control. However, a brief period of patchy reduced visbys may
develop at fog prone KRWI in the 08-11Z time range, though
confidence is not high enough to include any mention in the TAFs at
Outlook...VFR conditions and light winds will generally prevail
through mid to late week with strong subtropical ridging over the
area. A weakening and moisture starved dry cold front will approach
the area from the northwest late Friday/Saturday and will likely
stall before dissipating.