Area Forecast Discussion
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FXUS61 KPBZ 221920
Area Forecast Discussion
National Weather Service Pittsburgh PA
320 PM EDT SUN MAY 22 2016
Showers today will give way to drier and warmer weather through
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
A semi-stationary mid-level low continue to reside just to our
east and is throwing moisture back toward the eastern fringe of
the CWA still at this hour. However, contrary to the preponderance
of guidance, it hasn`t made very much westward progress during the
day. Instead, a second mid-level low that dropped southward and
brought colder air at 500 mb with it has managed to steepen the
lapse rates over Ohio and far western Pennsylvania enough to allow
for showers to develop in these areas which saw some breaks in the
clouds. The convective showers that have developed from this will
likely wind down a bit after sunset, while the activity associated
with the mid-level low to our east will likely linger along the
eastern edge of the CWA much longer into the night.
With all of that said, skies will start out mostly cloudy this
evening, but as convective activity fades, some scattering out of
clouds will be likely across the western two-thirds of the CWA.
Farther east, breaks in the clouds will be far less numerous.
Areas that do clear out may well see some fog development
overnight, as well. This will be due to the fact that dewpoints
remain within a few degrees of 50F. In addition, weak low level
advection will likely keep drier air from filtering into the CWA
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
Upper trough will gradually lift to the east, through late
Tuesday, being replaced by building high pressure. Residual
moisture and support from a shortwave rotating along the western
edge of the trough will bring the regeneration of showers and
some thunderstorms Monday afternoon, much like today. Generally
confined this to counties east of I-79. With more sunshine
anticipated west of I-79, near season temperatures were forecast.
By Monday night, high pressure will be building overhead, giving
way to mostly clear skies and warming temperatures, under
southwesterly flow through, early Wednesday.
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
Western CONUS troughing/Eastern CONUS ridging is forecast to
develop with general west-southwest flow over the Upper Ohio for
the latter half of the week. Warm, moist advection will support
increasing, shortwave-dependent precip chances as the weekend
approaches. With uncertainty in timing of individual shortwaves
embedded within the flow, have stayed close to climo POPs, which
is similar to a blend of model guidance. With building heights
and warm advection, anticipate above average temperatures through
the start of next weekend.
.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
IFR conditions will generally erode this morning with the slowest
improvements at KLBE and KMGW, where light NW upslope flow will
allow for stratus to linger the longest. As a mid-level low drops
southward and increases instability as the mid-levels cool, this
should allow for better cumulus development again this afternoon.
Scattered showers will develop across the area, and a few
thunderstorms will be possible. Coverage of thunder will not be
sufficient to include in the coded forecasts at this time. Fries
.OUTLOOK /SUNDAY NIGHT THROUGH THURSDAY/...
Restrictions are possible through Monday before the upper low