Area Forecast Discussion
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FXUS61 KPBZ 280532
Area Forecast Discussion
National Weather Service Pittsburgh PA
132 AM EDT Wed Sep 28 2016
An encroaching upper low will return rain to the Upper Ohio Region
for the latter half of the week.
.NEAR TERM /THROUGH TODAY/...
For now, made only minor changes to sky cover and hourly
temperatures through the overnight hours. Rest of forecast
.SHORT TERM /TONIGHT THROUGH FRIDAY/...
The Great Lakes upper low is forecast to dig southward across the
Mid, and Upper Ohio Valley for the latter half of the week. As
models have come into more consistent depictions, confidence in
the forecast of showery weather with reduced low-to-high
temperature spread has improved sufficiently to increase POPs to
likely and categorical numbers.
The better chances for sustained rainfall is over areas north of I
70 where a southeasterly wind will briefly support transport of
deeper Atlantic moisture into a frontal zone rotating around the
upper low on Thursday. Overdone, to inconsistent omega fields and
dry air encroachment into the mid levels of the mature low with
inconsistent frontal placement do not lend confidence to placement
of a heavy rain axis; thus, QPF was tempered between WPC/RFC
solutions over the past couple of forecast runs.
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
Most of the models lift the stubborn upper low from the middle Ohio
Valley at the start of the period into the eastern Great Lakes by
12Z Sunday. Details of individual waves rotating around the low
remain tricky at this distance, so kept PoPs fairly general, with a
slow decreasing trend through the weekend. Expect Sunday night into
the first portion of next week to be dry as a flattening ridge
arrives. Near-climatological temperatures will edge back above
normal by the end of the period with the departure of the upper low.
SuperBlend values were slightly knocked back early in the period,
but later numbers looked reasonable.
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
-- Changed Discussion --VFR conditions are expected through the day today, but clouds will
be on the increase as a strong upper level low pressure center
drops into the Ohio Valley. Showers are first expected this
afternoon in southeast Ohio near the upper low, and along the
eastern ridges as easterly flow allows moisture to pool. After
sunset, many locations will see ceilings drop to MVFR levels and
showers will slowly become more numerous. Cannot rule out a
thunderstorm in southeast Ohio before sunset, but chances are too
low to include in the TAF.
.OUTLOOK /WEDNESDAY NIGHT THROUGH SUNDAY/...
Periodic restrictions will remain through Saturday as the upper
level low lingers over the region.
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