Scientific Forecaster Discussion
fxus61 kpbz 200131
Area forecast discussion
National Weather Service Pittsburgh PA
931 PM EDT Tue Sep 19 2017
patchy fog overnight followed by a slight chance of isolated
showers and general thunderstorms south and west of Pittsburgh
Wednesday afternoon. Warm and humid conditions will continue
into early next week.
Near term /through Wednesday/...
Overnight, a frontal boundary will continue to struggle to move
southeast, while the mid-level shortwave and upper cold pool
begin to slip to our southwest into the middle Ohio Valley. This
may allow for a few isolated showers overnight in southeast
Ohio/parts of northern West Virginia but chances were too low
for inclusion in the zones. Cloud coverage will also persist
over the western half of the County Warning Area while the eastern half clears
out. With that...expect most overnight fog development from the
Ohio/PA border and east.
Above-normal temperatures were maintained overnight, a pattern
which will continue through the balance of the forecast period.
Short term /Wednesday night through Thursday night/...
the upper wave continues its trek to our south on Wednesday, and
with another modestly unstable afternoon, scattered showers and
thunderstorms will again be possible, mainly south of
Pittsburgh. Warm mid levels should keep activity suppressed to
After the wave exits, ridging will become even more firmly
entrenched over the Ohio Valley/Great Lakes as a deep trough
develops over the northwest U.S. This will lead to dry weather
and further warming through Thursday. Highs in the mid 80s will
become more common.
Long term /Friday through Tuesday/...
little change in the large-scale circulation pattern is expected
during the extended period, with the western trough/eastern
ridge setup maintaining, if not strengthening, through early
next week. As a result, a dry and quite warm forecast continues.
With 850mb temps soaring to the 17-19c range, most locations
outside of the ridges will soar well into the 80s. Cannot rule
out eventually needing a 90 degree reading or two in the warmer
locations. Continued to run with warmer temperatures than
suggested by superblend/mex.
Aviation /02z Wednesday through Sunday/...
fog development possible as has been the case for several
nights, however, cloud coverage along and west of the PA/Ohio
border will limit development over those areas.
Agc/fkl/duj/mgw/lbe should see IFR vis restrictions develop
again overnight under limited cloud coverage.
other than local morning fog, no widespread restrictions
expected through sun with building ridging.