Scientific Forecaster Discussion
fxus61 kpbz 221922
Area forecast discussion
National Weather Service Pittsburgh PA
322 PM EDT Tue Oct 22 2019
dry weather and seasonable temperature is expected until the approach
of weekend low pressure.
Near term /until 6 am Wednesday morning/...
rain has shifted east of the ridges with progress of a prefrontal
trough. Dry, cold advection is following with a wind shift to the WSW
upon frontal passage. Improved mixing with that shift is also
supporting gusts of 20 to 25 kt, which will persist until limited
decoupling later this eve as per a tight pressure gradient.
Wind and variable cloudiness should also limit overnight cooling - no
change was needed to the foredcast of near average low temperature.
Short term /6 am Wednesday morning through Thursday night/...
dry weather will persist through Thursday under the influence of sfc
high pressure south of the region. While colder air behind the front
will serve to keep the high temperature near average Wednesday, warm
advection with increasing southwesterly flow aloft will support
further temperature moderation for Thursday.
Gusty winds are expected Wed aftn due to a combination of strong
westerlies aloft, a fairly tight sfc gradient, and steeper low-level
lapse rates. The latest guidance and analogs both suggest 25-30mph
wind gusts at times.
Long term /Friday through Tuesday/...
there remains significant model variance on the progression and
strength of the next trough set to pass through the region this
weekend. Trends generally keep sfc high pressure in control for
Friday, promoting dry and warm weather. Then a trough will cross the
region, producing rain and introducing cooler air. Additional
shortwave troughs may provide more rain chances early next week while
maintaining a seasonable temperature.
Aviation /19z Tuesday through Sunday/...
degraded flight conditions will continue to improve over the next few
hours. The rain and associated cold front will clear the remaining
terminals by late afternoon. Dry air and mixing behind the front will
lead to a stratocu deck around 5kft which will gradually clear late
in the night.
Wind will increase behind the cold front, gusting in excess of 20
knots at times. Wind speeds will peak Wednesday afternoon with gusts
around 25 knots possible.
restrictions are possible again with a Fri cold front.