Area Forecast Discussion
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FXUS61 KPBZ 200829
Area Forecast Discussion
National Weather Service Pittsburgh PA
429 AM EDT Thu Oct 20 2016
Low pressure and a crossing cold front will bring widespread rain
to the region from late today into Friday. Much cooler weather
will follow for the weekend.
.NEAR TERM /THROUGH TONIGHT/...
Convection is exiting the northeast counties at this time having
left a band of 1-2 inch rain in its wake...extending from
Coshocton County east-northeast north of Pittsburgh into Clarion
County. Outflow from this complex generated some wind gusts in the
20-30 MPH range in general.
The warm front will continue to lift north today as a midlevel
trough continues to dig in the Mississippi Valley...putting a
good portion of the CWA in the warm sector. This will suppress
precipitation across much of the area through at least midday,
while some showers remain possible mainly north and west of
Pittsburgh. As low pressure rides up the Ohio Valley later today
along the advancing cold front, showers and some thunderstorms
will advance across the area mainly after 18Z. Likely and low-end
categorical PoPs reappear by 00Z. Lift and moisture is maximized
tonight with frontal passage and the approach of the still-digging
and negatively-tilting shortwave, leading to near 100 PoPs.
Going to hold off on the issuance of any flood watches for now
until areas of best rainfall can be ascertained later today.
However, amounts will need to be monitored along the
aforementioned heavy rain band from this morning. An additional
one to two inches may be seen in general from late afternoon into
tomorrow morning, and we may not be able to totally rule out
isolated flooding issues. Will mention in HWO.
Also of concern is marginal risk of severe storms across the
region as outlined by SPC. Increasing speed shear is noted on
model soundings for the afternoon, with 40 knots of flow at 700
mb. Lack of deep instability may be a limiting factor in a more
significant severe threat. Still, isolated strong to even damaging
gusts are a possibility, with large hail a lesser threat. Will
also mention this in HWO.
Increased high temperatures today, especially in the southeast,
with the influence of the warm sector. Readings in the 80s appear
likely here. Little change to lows tonight...mainly in the upper
40s to the mid 50s.
.SHORT TERM /FRIDAY THROUGH SATURDAY/...
The frontal precipitation will drift eastward Friday morning with
additional showers developing behind the boundary in the strong
cold air advection and passage of the upper level trough axis.
Much colder weather will follow for the weekend as the upper
trough develops over the Eastern CONUS. Scattered showers will
remain in the forecast through at least Saturday morning, with
focus shifting to the north and ridge zones, as cold advection
continues and shortwaves in northwest flow traverse the area.
By Saturday afternoon, the much drier air aloft, which will work
to suppress inversion heights, will eventually make it closer to
the surface, bringing and end to any lingering showers. Still
expect to see a good deal of cu over the area Saturday with the
cold pool aloft remaining anchored over the area.
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
Dry, but seasonably cool conditions will return Sunday as warmer
air slowly works back into the area. Ensemble solutions continue
to push a weak front through the area sometime on Monday, which
may provide another risk for scattered showers. High pressure
builds in for the remainder of the long term.
.AVIATION /08Z THURSDAY THROUGH MONDAY/...
Convective complex in southeast Ohio is moving towards western PA
at this time, bringing brief IFR conditions in heavy rain to BVI
over the next hour, and possibly PIT soon thereafter if it holds
together. FKL may be impacted with IFR in a couple of hours as
well as lighter rain develops. Mostly VFR conditions will hold
southeast of a PIT/DUJ line. Behind an advancing warm front,
conditions will remain VFR in the warm sector today as rain
coverage temporarily wanes, although MVFR ceilings may hold on
north of I-80.
As the cold front advances this afternoon, coverage of showers and
storms will increase from west to east, eventually overspreading
the region tonight. Flight conditions will deteriorate through
MVFR to IFR by the end of the TAF period.
.OUTLOOK /THURSDAY NIGHT THROUGH MONDAY/...
Periodic restrictions are expected through Saturday as low
pressure and subsequent upper troughing cross the area.