Area Forecast Discussion
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FXUS61 KPBZ 200123

Area Forecast Discussion
National Weather Service Pittsburgh PA
923 PM EDT Mon Jun 19 2017

An upper trough will maintain daily chances for showers and
thunderstorms and cooler conditions through midweek.


Showers are largely tapering down and moving out as one
shortwave trough swings through. Upstream convection showing
similar downward trend. With this in mind, will keep the
previous forecast of dry weather tonight intact. Clouds will
gradually begin to clear from the southwest tonight.
Temperatures will remain close to the seasonal average tonight.

Tuesday should generally be a repeat of today, although with
lower chance PoPs until the next shortwave approaches late.
There are timing differences amongst the model guidance with
this wave, so nothing more than low chance PoPs, with a focus
closer to the upper trough.


Upper trough will remain situated across the Great Lakes through
Wednesday before departing to the east and being replaced by
weak upper ridging/nearly zonal flow for Thursday. Again, models
continue to time the shortwave passage differently Tuesday
night/Wednesday with the GFS suggesting a boundary will hang up
across the region and help for invitation Wed afternoon, while
the NAM pushes the boundary and precipitation chances south of
the forecast area. With low confidence, will keep no more than
slight chance PoPs in the forecast at this time.

Models generally agree in rising heights and dry conditions on
Thursday with temperatures moderating to near or above seasonal


The progressive flow will make any long term forecast
difficult, and the models resolve the evolution of a potential
tropical system differently. With this in consideration, have
opted to stay close to a blend of guidance which keep conditions
mostly dry until late Thursday. After this time, deeper moisture
will support higher PoPs and warming temperatures until an upper
level trough deepens over the central CONUS late.


Mid-level cloud deck associated with the passage of a shortwave
trough around the upper level low will begin to erode from the
southwest. As it does, some lowering may occur. This will leave
FKL and DUJ as the only sites with an outside chance of dropping
to MVFR. Any restrictions that do occur overnight will quickly
be alleviated Tuesday morning with increased mixing.

Winds will generally be from the west at 10kts or less.

Brief restrictions are possible through mid week as an upper
trough slides over the region.




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