Area Forecast Discussion
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FXUS61 KPBZ 270129
Area Forecast Discussion
National Weather Service Pittsburgh PA
929 PM EDT Wed Apr 26 2017
Warm, dry weather will be interrupted by showers
and storms with a Thursday cold front.
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
-- Changed Discussion --Generally light southerly flow will continue over the area
overnight as high pressure starts to slip eastward. Subsidence
from this should allow for clear skies to remain (outside of
some convective blow-off cirrus which may skirt the western
areas through midnight), which coupled with dewpoints in the
50s, which will be about the lows in the morning, as well as wet
soil across the eastern portions of the CWA, may allow for some
local fog formation around Jefferson County, PA, or amongst the
ridges. Otherwise, clear and mild conditions will prevail
through morning. Fries
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.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY/...
A cold front associated with an occluding system will cross the
CWA during the late afternoon/early evening. Latest model runs
have followed suit with previous runs progging a slightly faster
The pre-frontal environment during the afternoon will feature
plenty of shear but instability looks to be marginal as
moisture advection will be weaker this far north as the surface
low occludes and daytime max temperatures are forecast to be
slightly cooler than previous advertised which will make warmer
air aloft in the lower levels difficult to overcome. Thus, SPCs
continued marginal risk seems appropriate.
Without any other triggers...activity may be limited to along
the frontal boundary as it crosses. In any case, there would
still be potential for damaging winds and/or hail in with any
storms that develop strong updrafts given the wind fields.
Dry weather returns behind the front Thursday night and Friday as
ridging builds aloft.
Above normal temperatures will continue.
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
An active pattern is figured for the weekend into early next
week. A few shortwaves will cross in continued moist southwest
flow along the front of a broad trough, leading to rain chances
for Saturday and Sunday. Timing remains tricky, but Saturday
night currently looks to be the period with the lowest coverage
in the warm sector. Temperatures remain above normal. The
trough lifts out as a closed upper low into the Great Lakes by
Monday, pushing a fairly strong boundary across us. Given system
strength, the amount of moisture, and a possibly negative tilt
to the upper trough, strong storms appear possible. Behind this
system, quieter weather and seasonable temperatures are expected
into the middle of next week.
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
High pressure will maintain clear skies and light winds through
the night. Some local fog will be possible around KDUJ, but
confidence precludes inclusion in the forecast. Increasing
southerly flow will characterize Thursday. A cold front will
move from west to east across the area during the afternoon.
Showers and thunderstorms with very gusty winds will be likely
with this. Some restrictions are possible in and behind the
Periodic restrictions are possible this weekend a front stalls
across the region, then returns northward as a warm front.
Restrictions are likely Sunday night and Monday with cold-front-
associated showers and storms.