Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Pittsburgh PA
959 am EDT Monday Aug 31 2015
warm...humid conditions and sparse rain chances are expected
through the upcoming week.
Near term /through tonight/...
weak upper low...evident mainly on water vapor imagery...will
stay nearly stationary or retrograde slightly west today. With a
warm and humid airmass in place...this wave may be enough to
support some diurnal convection later this afternoon but warming
in the middle levels may cap any showers and thunderstorms...save for
the high terrain. Have made no changes to the probability of precipitation today...with
very low end chance probability of precipitation carried.
With heights increasing...expect temperatures to warm well into
the 80's by this afternoon but weak mixing and low level moisture
may keep temperatures from hitting 90 today.
Clear skies and light wind tonight should promote fog development
tonight...especially in the river valleys. Low temperatures will be
warmer than average and based on a blend of model guidance.
Short term /Tuesday through Thursday/...
synoptic pattern favors the building of a large ridge over the
eastern Continental U.S. Tuesday. Despite this...low-level moisture lingers
across southern zones enough to generate isolated
showers/thunderstorms with strengthening low-level lapse rates.
With warm middle-level temperatures in place...keeping probability of precipitation limited to
slight realm...even as an embedded weak trough passes through the
ridge Tuesday evening. The upper ridge then amplifies by middle-week
reinforcing the trend to drier and warmer conditions.
Long term /Thursday night through Sunday/...
no major changes to the extended period as the impressive eastern
Continental U.S. Ridge further amplifies reaching into eastern Canada. Cannot
rule out diurnal rain chances...especially in the higher terrain
as the center of the upper high moves north of the area and return
flow establishes a moisture feed from the middle- Atlantic.
Still...largely dry conditions will persist into and through the
weekend. Temperatures will play out like a broken record...nearly
the same everyday...several degrees above average through the
period. The next real chance of a rain producing system for the
entire forecast area could come with a front slated sometime early
to middle of next week. Tax
Aviation /14z Monday through Friday/...
general VFR into this evening with light southwest winds. Isolated
showers and thunderstorms will be possible late afternoon mainly
near the ridges...but nothing expected at any port. Patchy MVFR to
IFR fog expected before sunrise overnight.
Outlook...Monday night through Friday...
general VFR except for patchy morning fog the remainder of the