Wednesday, May 24, 2017, 4:18 AM EDT
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Area Forecast Discussion
||Wed, Dec 31, 7:00pm EST
FXUS61 KPBZ 240701
Area Forecast Discussion
National Weather Service Pittsburgh PA
301 AM EDT Wed May 24 2017
Unsettled weather will return for the remainder of the week as
an upper-level disturbance moves slowly across the Ohio Valley.
.NEAR TERM /THROUGH TODAY/...
As a deep upper low slowly migrates toward the western Great
Lakes today, a couple of weak short waves troughs embedded in
southwesterly flow aloft are set to transit the area. This fact
combined with a rather haphazard low/mid-level deformation field
have allowed for scattered showers to continue to develop across
the area early this morning, and it is expected this trend will
continue through much of the day.
More coherent shower activity will start to encroach on the area
late in the day as the upper low over the western Great Lakes
starts to migrate eastward. Even still, due to abundant layer
moisture ahead of this system, clouds will be common through the
day with diurnal ranges looking rather subdued as a result.
.SHORT TERM /TONIGHT THROUGH SATURDAY/...
The upper low will gradually first dig into the mid-Mississippi
Valley before slowly ejecting toward our area. This will all
take through Thursday to occur. As it does so, lapse rates will
steadily increase due to mid-level cooling even as boundary
layer temperature remain rather subdued due to rain cooling and
abundant cloud cover. As such, chances of thunderstorms and
showers will remain in the forecast with generally below normal
By Friday, the upper low will have shifted toward New England
with northwesterly flow in control and a bit of drier air
working into the region. This will be rather short-lived,
however, as the H5 ridge axis looks to shift through the area by
Saturday with broad southwesterly flow becoming established.
This will allow for more humid and warmer conditions to arrive
for the weekend. However, it will also bring in chances of
showers and thunderstorms yet again. In fact, some solutions
have featured an MCS traversing the region on Saturday. Stay
tuned on that.
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
The pattern going into next week looks to continue to amplify as
an upper low again drops into the Mississippi Valley with a
downstream ridge popping up rapidly along the eastern seaboard.
Unfortunately for us, we will be stuck between these two areas
with broad southwesterly flow remaining in place and thus
abundant moisture streaming toward the area. As a result, shower
chances will remain with temperatures not too far from normal.
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
VFR conditions are expected to deteriorate to MVFR by morning in
some areas mainly near and W of I 79 as low level moisture
increases with a crossing shortwave. Maintained a VCSH mention
in the TAF with sct shower coverage expected. Improvement back
to VFR is expected by late morning/early afternoon before
deterioration back to MVFR in showers late in the day with
approaching low pressure.
Increasing SE winds are expected today with an increasing
pressure gradient, with a few 20-25kt gusts especially for the
higher terrain ports.
Restrictions are likely through Thu night, and again over the
weekend, with low pressure.