Area Forecast Discussion
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FXUS61 KPBZ 271638

Area Forecast Discussion
National Weather Service Pittsburgh PA
1138 AM EST Mon Feb 27 2017

A series of disturbances will keep periodic rain in the
forecast through mid week until the passage of a cold front
returns wintry weather for the last half of the week.


Light rain is just starting to overcome the dry air below 800 mb
that was present on this morning`s 12z KPBZ sounding. The first
reports of rain have started to trickle in over the past half of
an hour around Zanesville, roughly in line with both large scale
and hi-res model timing. As the wave generating the warm
advection light rain over the area slides ENEward over the
afternoon, this rainfall will likely develop farther ENE across
the area. Likely PoPs have been maintained for this activity,
however saturation is over a fairly limited time interval, and
lift is somewhat unimpressive, so QPF remains light.

The system looks to clear the eastern portions of the area this
evening. Layer RH values start to fall off late in the evening
from S to N, likely revealing some clearing before clouds look
to start to increase from the west ahead of the next system.
Temperature expectations overnight will likely be modulated by
the exact interval and longevity of clearing with the low
temperature forecast gradated from cooler east and warmer south
as a result. Fries


Precip chances should end this evening as the shortwave exits
and the warm front lifts N of the area. The region is progged to
be in the warm sector in SW flow ahead of a trough advancing ewd
from the Western CONUS. Several shortwaves and increasing low
level jet support are progged to cross the area with periodic
showers expected Tuesday and Tuesday night. There is a chance of
thunderstorms Tuesday night with elevated instability and
increasing shear.

The western trough is progged to approach the Great Lakes region
Wednesday as an associated surface low tracks from the Midwest
into Southern Ontario. Increasing speed and directional shear
is progged through the day as the low`s associated cold front
approaches. 500mb winds approaching 100kt on both NAM and GFS
model soundings is indicative of the strong jet progged over
the area. Severe thunderstorms are possible if enough
instability develops during the day. This will be monitored over
the next couple of days, but a mention will be included in the
hazardous weather outlook.

Broad upper troughing is expected over the area Wednesday night
and Thursday, along with eventual lake and terrain enhancement
in cold advection. This should keep snow showers chances in the
forecast. Temperatures are expected to be 20 to 25 degrees above
average Tue and Wed, returning to near or below seasonal levels


Broad upper troughing is expected to continue through late
week, with a reinforcing crossing shortwave/surface low with
some snow Thursday night and Friday. General zonal flow is
progged by the weekend as the trough exits, with mainly dry
conditions and moderating temperatures.


Restrictions of the MVFR variety will be likely shifting ENE
from ZZV toward PIT through the afternoon today as light rain
develops across the region ahead of a weak system. While
rainfall may not make it all the way to FKL, a period of MVFR
cigs may this evening for a time. Skies should start to scatter
out beyond the evening for a period at most sites with a window
of VFR conditions before the next system on Tuesday.

Restrictions are likely Tuesday as precip develops with another
shortwave in strengthening wsw flow. More restrictions and wind
problems can be expected with, and in the wake of a Wednesday
cold front.




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