Area Forecast Discussion
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FXUS61 KPBZ 250133
Area Forecast Discussion
National Weather Service Pittsburgh PA
933 PM EDT Sat Sep 24 2016
Another day of dry weather and seasonable temperatures are expected
on Sunday before a cold front brings rain and scattered
thunderstorms on Monday.
.NEAR TERM /THROUGH SUNDAY/...
-- Changed Discussion --Dry air is rapidly moving south of the Mason-Dixon line behind a
cold front that cleared the area earlier in the day. Dewpoints
have already fallen off into the 40s across the majority of the
area north of Pittsburgh with values near 40F encroaching upon the
northern fringe of the area. These drier values will continue to
surge southward this evening as surface high pressure settles into
the New York/Pennsylvania border area. This should keep subsidence
over the area with surface flow trending off overnight toward
morning. As such, a few of the lower spots in Forest County as
well as possibly Garrett County may manage to see some frost
depending upon how much the wind backs off overnight. Coverage
does not seem to be anywhere near enough to contemplate an
advisory, however inclusion of the possibility in the grids seems
to be prudent. Fries
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.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
Clouds will be on the increase Sunday night in advance of a cold
front that will cross the region Monday afternoon. Continued to inch
pops up in the forecast. Depending on the exact timing that the
front comes through, cannot rule out the potential for some strong
thunderstorms considering the respectable wind shear and instability
that could be present. The bulk of the rainfall should be through
the area after Monday evening, with a reinforcing shot of cold air
arriving Monday night into Tuesday. Although warm advection will
bring warmer temperatures on Monday, the coldest high temperatures
of the season so far are forecast on Tuesday. Widespread highs in
the 60s are expected, and isolated locations could remain in the 50s.
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
Both the 00Z and 12Z runs of the ECMWF kept a trough across
the eastern United States throughout the forecast period, which
was an outlier solution compared to the GFS, Canadian, and
ensembles solutions, and was not used for this part of the
forecast. As an upper trough moves across the region Wednesday
and Thursday, cloud cover will remain across the area. Although
the wind direction is still a bit uncertain those two days, lake
effect rain showers will be possible while northwest flow
develops off Lake Erie. By Friday winds will develop an easterly
component, which will allow sunny skies to return. Slightly below
normal temperatures are expected through the period.
.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
General VFR can then be expected through Sunday with exception
for pre-dawn fog at southern terminals where boundary layer
moisture is more likely to pool in the wake of the front. North
wind will gradually acquire an easterly component, but remain
light as the surface high settles toward the area.
VFR conditions will return to all sites by Sunday morning as high
pressure holds through the weekend.
.OUTLOOK /SUNDAY NIGHT THROUGH THURSDAY/...
Restrictions are likely with a Monday cold front.