Area Forecast Discussion
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FXUS61 KPBZ 210306
Area Forecast Discussion
National Weather Service Pittsburgh PA
1006 PM EST Fri Jan 20 2017
Mild weather will continue through the weekend. Widespread rain is
expected to move back into the region by Sunday.
.NEAR TERM /THROUGH SATURDAY/...
Abundant boundary layer moisture remains as evidenced by
dewpoints largely in the lower 50s across the central portions of
the area. This air mass will continue northward slowly overnight,
while warm advection will be even stronger off the deck. The net
result looks to be strengthening inversions and the trapping of a
fair bit of moisture below them. With this in mind, fog looks to
be a concern over much of the northern half of the area. Farther
south, a bit of drier air has worked in and allowed dewpoints to
fall off a bit, however even here a bit of fog may be possible.
With warm advection off the surface and the likelihood of stratus
development, model soundings look to also be supportive of some
drizzle across the northern two-thirds of the CWA as well as in
the ridges. Thus, while measurable rainfall seems unlikely,
patchy drizzle may be an issue in spots into the morning hours of
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
The short term portion of the forecast will be the wettest part of
the week ahead. ECMWF/GFS/NAM have come to a bit of a compromise
over the last couple of days for the track of the upper low that
will develop across the Southern Plains, track near the Gulf
Coast, then north up to central Pennsylvania. While there is still
some run to run variability, occasional rain is expected and it
appears that Sunday night and Monday will likely have the most
rain. Temperatures will remain warm enough that only a few
snowflakes are expected to mix in with rain Monday morning in the
ridges, and precipitation could begin to wind down as snow Monday
night as temperatures drop back towards the freezing mark.
.LONG TERM /TUESDAY THROUGH FRIDAY/...
Any remaining showers should wind down Tuesday, with cold enough
air that many locations could see some minimal snow accumulation.
There should be a bit of a break between systems before low
pressure races across the Great Lakes on Wednesday. Behind the
low, northwest flow aloft will allow for scattered showers to
continue through the rest of the forecast period. Temperatures
will drop through the end of the work week, with below normal
values expected by Friday.
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
VFR conditions, that are currently being experienced at several of
the TAF sites south of KFKL and KDUJ, which are in the vicinity of
the warm front, will slowly diminish as the night progresses. With
plenty of low level moisture, and strengthening inversion
expected, it appears that conditions should fall back to low
mvfr/ifr in fog and/or stratus. Confidence is greatest to the
north, where little improvement is expected the entire night. As
you go further south, it may be more of a late night/early morning fog
concern than a stratus concern. Have adjusted the TAFS
accordingly based on these thoughts and the latest consensus of
model guidance and bufkit profiles.
Wind will remain light out of the wsw through the period.
More restrictions are likely Saturday night into Monday with slow
moving low pressure.