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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KPBZ 061941
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
341 PM EDT Thu May 6 2021

.SYNOPSIS...
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A crossing front will usher in colder weather and periodic
precipitation for the weekend.
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&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
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No changes were needed for the eve update as temperature moderation
toward average values is underway via warm, moist advection on swly
flow ahead of an encroaching cold front. This will also increase
precipitation chance to categorical numbers from west to east,
generally after 9 PM this evening with the progression of the cold
front. Poor lapse rates and unfavorable timing should hamper
instability as the cold front crosses, thus no thunder is
anticipated.
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&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
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Showers should be ongoing early Friday as the cold front continues
its trek across the forecast area, with sfc nwly flow reinforcing
cooler air in its wake. As such, sub-average temperature is expected
once more, with daytime high temperature in the low to mid 50s. As
the cold front departs, cold upper troughing with embedded shortwave
activity may support lingering showers and isolated tstms through
the remainder of Friday.

Increased cloud cover and continued precipitation potential should
negate widespread frost/freeze concerns during the pre-dawn hours
Saturday despite another night of temperature in the 30s.

A final shortwave passage within upper troughing is expected to maintain
scattered precip chances on Saturday, with sufficient boundary layer
conditions supporting rain/snow potential across higher elevations.
Precipitation chances should then diminish as brief sfc high pressure
builds by Saturday PM.
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&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
A pattern shift is progged Sunday as flattened flow commences,
supported by interaction of cut-off Pacific NW low pressure and
persistent low pressure near Hudson Bay, Canada. Developing sfc low
pressure across the central Plains should promote widespread precipitation
chances Sunday into Monday, with brief high pressure returning dry
conditions on Wednesday.

Rather neutral temperature advection in zonal flow should maintain
cool conditions through the extended period.

&&

.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
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VFR will prevail until crossing low pres deteriorates conditions in
rain during the predawn of Friday. Cigs will likely drop to MVFR,
followed by IFR after 12Z tomorrow. Any improvement of Friday aftn
will be brief though as cold advection will spawn MVFR stratocu and
additional showers be eve.

.Outlook...
Restrictions are likely through the weekend with cold upper
troughing.
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&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
PA...None.
OH...None.
WV...None.

&&

$$