Area Forecast Discussion

Pittsburgh, PA

Forecast Discussion for PBZ NWS Office
FXUS61 KPBZ 251051

Area Forecast Discussion
National Weather Service Pittsburgh PA
551 AM EST Sun Feb 25 2018

Rain will end today as a cold front crosses. A welcome period of
dry and mild weather will take hold for the first part of the
work week as high pressure takes control.


Rainfall has come in a bit under expectations, and little in the
way of flooding has been reported thus far. Have cancelled a
portion of the Flood Watch where rain has mostly ended. Some
Areal Flood Warnings remain for isolated issues.

Cold frontal passage occurs in the 12Z-18Z window today,
with gusty winds developing behind the boundary with downward
momentum transport. Some gusts of 50-55 MPH are occurring over
western Ohio behind the boundary. Expecting our gusts to come in
a bit below this level after looking at soundings. Did issue SPS
for gusts up to 45 MPH, with the potential for a short-fuse
advisory if the threat for higher gusts increases. Hi-res
models depict a line of low- topped showers developing along the
boundary. Have used the HRRR to time this activity across, with
most precipitation departing with the front by 18Z. Clouds will
linger for a few hours behind the front, but expect decent
clearing areawide by sunset. By this time, high pressure will
start to nose in from the lower Ohio Valley, loosening the
pressure gradient and allowing wind gusts to diminish.

Temperatures will continue to shoot up towards sunrise, pushing
60 degrees across the south. Steady or slowly falling
temperatures are expected behind the front this afternoon.


The region will receive a much needed dry spell during this
period. High pressure will expand from the lower Ohio Valley
tonight and eventually center itself over the central
Appalachians by Tuesday. After lingering clouds depart tonight,
plenty of sunshine is figured for both Monday and Tuesday.
Temperatures will be a bit cooler Monday, but still above
normal, with readings in the upper 40s to mid 50s. Developing
southwest flow behind the high Tuesday will allow a bit of
warming, with some 60 degree readings reappearing near the
Mason-Dixon Line.


Moisture from the southern stream reappears on Wednesday,
bringing a chance of light rain as a warm front approaches from
the Tennessee Valley. A split-flow pattern tracks low pressure
centers to the north and south of our region, eventually phasing
into a single low off of the east coast. Details of this remain
murky, but rain appears likely Thursday and Thursday night in
this pattern. Cooler air arrives starting Thursday night,
knocking temperatures back towards climatology and possibly
allowing snow to mix in along I-80. Accumulation potential
appears meager. Showery precipitation will continue in northwest
flow through Friday night, with increasing snow coverage, before
tapering off Saturday as midlevel ridging approaches.


With the warm front lifting north of the area and the cold front
yet to come this morning, we find ourselves temporarily in the
warm sector of the broad low pressure system. VFR or at worst
MVFR ceilings have been common in the warm sector and will
continue until the frontal passage from west to east this
morning. In the wake of the front, dry air will allow clouds to
scatter out and ceilings to raise. VFR is then expected through
the balance of the TAF period.

Low-level wind shear will be alleviated with the frontal
passage, but a surface wind shift will also accompany. Winds
will quickly shift from southerly to westerly behind the front,
gusting into the 20-30kt range and possibly (temporarily)

High pressure building in for early this week will limit
restriction potential.


With rainfall totals coming in below expectations, any flooding
of the mainstem rivers should fall in the minor flood spectrum
at worst. Also, as of this writing, few reports of small stream
and creek issues have been received in the locations where areal
flood warnings and advisories are in effect. Perhaps some
flooding will be discovered with daylight, but overall, the
threat of widespread high water issues is decreasing. Still, the
flood watch will remain intact for now, and mudslides remain a
concern given the saturated ground and continued runoff.

No river flood warnings are in effect at this time, but remain
possible as the effects of the recent rain are considered.


MD...Flood Watch through this evening for MDZ001.
PA...Flood Watch through this evening for PAZ009-014>016-021>023-
WV...Flood Watch through this evening for WVZ002>004-012-021-



NWS PBZ Office Area Forecast Discussion