Area Forecast Discussion
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FXUS61 KPBZ 010906
Area Forecast Discussion
National Weather Service Pittsburgh PA
506 AM EDT Sat Oct 1 2016
Upper level low pressure will continue to produce a few showers
across the region into the weekend.
.NEAR TERM /THROUGH TONIGHT/...
The semi-resident upper low will continue to reside in the Ohio
Valley through the near term forecast period. Hi-res models have
started to catch onto where shower development has been ongoing in
bands around the upper low overnight. Additionally, they seem to
be handling the influx of deeper layer dry air evident on water
vapor imagery that is advecting into the area. This combined with
a bit of an easterly jaunt of the S-N oriented jet streak that
develops on the east side of the upper low, which results in upper
divergence trends generally east of the Chestnut Ridge. This means
dynamical forcing over our area will not be all that impressive.
However, as the upper low starts to meander northeastward a bit
through the day, colder mid-level temperatures will allow for
steeper lapse rates to favor the formation of a shower or two,
especially over the northwestern CWA. With dry air seemingly set
to win the battle over the area, just scattered to isolated
showers were carried for most areas through the day.
With drier air moving in, it stands to reason that a few more
breaks in the clouds are likely today. This combined with a slow
trending of low level flow from the east to southwest during the
day should allow temperatures to go up several degrees from those
seen on Friday.
The upper low will continue to migrate northeastward tonight
allowing for deeper layer southwesterly flow to become
established. This will allow for the dry slot to make serious
inroads into the CWA, which means most areas should dry out for at
least a period going into Sunday morning. Fries
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
Slow moving low will accelerate eastward Sunday, with the center
of the low passing near Lake Erie. As it does, the remaining
moisture will fuel scattered rain showers, primarily north of
Pittsburgh. Steepening low-level lapse rates and impressive wind
shear could generate a few thunderstorms, but the lack of deep instability
will likely limit overall growth.
The low will still be in the neighborhood Monday, but with our
location on the dry southwest quadrant, showers potential will be
much more limited. Compressed diurnal ranges will exist through
Monday, as highs will be near average, but lows will still be a
few degrees above average.
.LONG TERM /TUESDAY THROUGH FRIDAY/...
High pressure establishes over our area for the middle of next
week. This will bring dry conditions back to the area, with
temperatures gradually increasing through the week. By the latter
part of the week, temperatures will be well above-average.
There are still a lot of questions as to when the next
rain will approach. This is will largely be dependent on the
timing of the digging trough through the center of the country
middle of next week. This digging trough looks to play an
important role on the evolution and potential impacts of Hurricane
Matthew. We will continue to monitor these features very closely,
but at this very early stage, impacts to our forecast area do not
.AVIATION /09Z SATURDAY THROUGH WEDNESDAY/...
Weakening surface flow will be evident over all sites through the
night. Combined with scattered showers, this should allow CIGs to
trend downward through the night, however VIS restrictions should
be minimal and fairly local. Drier air will move into the area on
Saturday in the mid-levels, however colder air aloft will mean
showers should redevelop with the upper low drifting nearby. Even
still, conditions should largely improve to VFR at most sites.
.OUTLOOK /SATURDAY NIGHT THROUGH WEDNESDAY/...
Brief IFR/MVFR restrictions will linger into Monday when the
upper level low finally departs.