Scientific Forecaster Discussion
fxus61 kpbz 212317
Area forecast discussion
National Weather Service Pittsburgh PA
717 PM EDT Mon Oct 21 2019
a cold front will bring rain and gusty wind overnight and early
Tuesday. Dry weather and seasonable temperature will follow.
Near term /until 6 am Tuesday morning/...
Evening update: no major changes needed to the forecast.
Previous: showers associated with the warm front continue to track
north and east across western Ohio. With the current track of
precipitation, low-level jet axis, and prevalence of dry air should
limit measurable precipitation.
Rain is expected to develop over eastern Ohio by around midnight, and
progress into western PA during the predawn of Tuesday. Strong
forcing and climatologically high precipitable water values will support an
efficient period for rainfall which reinforces the categorical pops.
Strong warm advection/southerly flow will keep temperatures elevated
overnight, with lows 10-15 degrees above seasonal norms.
Short term /6 am Tuesday morning through Thursday/...
surface cold front will complete it's passage around midday Tuesday.
High pressure will then build over the region through the latter half
of the day. Subsidence will support mostly sunny conditions, which
should allow for deep mixing/gusty wind as cold advection continues
both Tuesday and Wednesday. At this time, momentum Transfer values
suggest 25-30mph wind gusts will be possible.
Surface ridging will remain in place on Thursday, though the trough
deepening through the central US will tighten up a baroclinic zone
just west of the region. Temperatures will remain near seasonal
Long term /Thursday night through Monday/...
southwesterly flow ahead of the aforementioned central Continental U.S. Trough
will return a narrow band of moisture to the region. Shortwave
passage through the trough may promote surface low development and
precipitation but at this time, the model guidance varies. Generally
stayed in line with ensemble guidance and near seasonal temperature
through the period.
Aviation /23z Monday through Saturday/...
VFR will deteriorate from the west in the predawn of Tuesday.
Rain is projected to commence at Zanesville shortly after midnight,
and at appoximately 10z at Pittsburgh. Expect MVFR until frontal
passage completes by about 16z.
Given the encroachment of a llvl jet with the frontal advance, llvl
wind shear was included.
general VFR is anticipated for the remainder of the week.