Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Pittsburgh PA
353 am EDT Mon Oct 24 2016
a cold front is bringing lower temperatures back to the area. A
mostly dry forecast is maintained through midweek, before a system
returns rain chances area wide.
Near term /through tonight/...
light rain showers diminishing quickly along a cold front
dropping in from the north. The front is expected to continue
south through the area this morning. Strong northwest flow behind
the front will quickly advect cooler air in from the north. As a
result, temperatures will should follow somewhat of a non-diurnal
trend today with many locations already seeing their high
With cooler air pouring over the warm waters of Lake Erie,
limited production of lake-enhanced showers is expected into the
afternoon. Thus, chance pops were maintained, primarily north of
I-80. Temperatures tonight will be back to below normal.
Short term /Tuesday through Thursday night/...
building surface high pressure will return dry weather to the
area through Wednesday. An upper-level trough will dig into the
western Great Lakes early Wednesday, strengthening the surface low
as it approaches from the west.
Modest isentropic ascent across the warm front will lead to a
gradual increase in clouds by Wednesday morning. Several models
generate qpf with this feature as it pushes north of the area
Wednesday night. Model soundings reveal deeper moisture resides
aloft, with a low-level dry layer. This dry layer, along with a
slower evolution of the parent low, should delay onset of
precipitation. Continuing to hold off pops until the surface low
nears Wednesday night.
Likely pops have been maintained for Thursday as the deepening low
tracks just to our north. A strengthening of the low-level jet
should increase rain efficiency Thursday. This is noted in fairly high
qpf amounts seen across model guidance, especially the 00z GFS.
For the time being, have stayed at or just below wpc qpf guidance.
Long term /Friday through Sunday/...
brief ridging will dry out the forecast Friday, but another trough
will already be approaching from the west. Unsettled weather and
cooler than seasonal average temperatures will hold for the
weekend until the western Continental U.S. Ridge begins to break down early
next week. In general, followed close to the superblend guidance
for construction of the extended period.
Aviation /07z Monday through Friday/...
general VFR with gusty southwest surface wind will continue to give
way to scattered showers, MVFR deterioration, and a wind shift to
the northwest as a cold front crosses the upper Ohio Valley airspace
overnight. Low level wind shear should persist for lbe through early
morning as the low level jet exits. Despite a trailing disturbance and
slight showers chances, improvement to VFR is anticipated by midday
as mixing lifts the cloud bases.
Outlook /Tuesday through Friday/...
the next chance for general restrictions will be with Thursday