Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Pittsburgh PA
245 PM EDT Tuesday Oct 13 2015
passage of todays front will Herald sub average temperatures for
the remainder of the week. Lows near freezing are expected this
Near term /until 6 am Wednesday morning/...
a shortwave should continue to bring low/slight shower chances
across the area early this evening. Another shortwave advancing
through a broad upper trough is expected to cross the region
overnight... with additional showers possible especially north of I 80
where some limited lake enhancement is possible. Lows should be
near seasonal levels using the latest GFS MOS guidance.
Short term /6 am Wednesday morning through Friday/...
the broad upper trough is prognosticated to persist through the rest of
the week. Low chances for showers are expected again north of I 80
Wednesday again with limited lake enhancement. A clearing trend is
expected Wednesday night/early Thursday as weak surface ridging briefly
builds in. The next cold front is prognosticated for a late
Thursday/Thursday night approach and passage. Continued with chance
probability of precipitation as some model disagreement continues with the amount of
available deep moisture.
Temperatures should average a few degrees below seasonal levels
using a blend of the latest GFS MOS and direct GFS guidance.
Long term /Friday night through Tuesday/...
broad upper troughing is prognosticated across the eastern Continental U.S. Into
the weekend with reinforcing cold fronts resulting in
progressively colder temperatures...with near freezing temperatures by
the start of the new week. Thereafter...models indicate temperature moderation
under shortwave ridging. The long term forecast was based on a
blend of wpc and GFS MOS guidance.
Aviation /19z Tuesday through Sunday/...
VFR is expected to dominate the afternoon although cold advection
will Herald cumulus and stratocu development...and some additional scattered
showers in vicinity of terminals from pit eastward.
Genl stratocu bases should drop below MVFR thresholds tonight as
colder air encroaches/relative boundary layer moisture increases.
Outlook...Wednesday through Sunday...
restriction potential with MVFR stratocu may linger into early
Thursday as cool flow off the Great Lakes persists.