Area Forecast Discussion
Issued by NWS -- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KPBZ 200903
Area Forecast Discussion
National Weather Service Pittsburgh PA
403 AM EST Fri Jan 20 2017
Rain will return to the region today as an upper level system
moves through. The mild pattern will continue through the weekend.
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A tilted and elongated trough will swing through the area this
morning. The associated surface warm front will move through in
the same direction, just ahead of the aforementioned upper level
system. Showers will overspread the area from southwest to
northeast. The showers will sweep through the area rather
quickly, with the back edge reaching the northeast by late
Temperatures will average well above normal today.
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
With upper level heights rising quickly this evening and the
atmosphere drying out, have continued with the previous thinking
of keeping Friday night and Saturday dry.
The next strong upper level system begins to take shape over the
Tennessee Valley Sunday morning. Moisture will once again begin to
stream northward on the eastern side of the developing 500mb low.
At the surface, low pressure will rapidly develop over OK Sunday
morning and move rapidly toward the east coast, reaching the Mid-
Atlantic region Sunday afternoon. Have kept the highest PoPs
Sunday during the afternoon hours, in conjunction with movement
of the southern stream low.
Temperatures both Saturday and Sunday will be well above normal
with Saturday providing the warmest temperatures.
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
There is still much uncertainty pertaining to the forecast Monday
and Tuesday, as even the ensembles are trying to come to an
agreement on the speed and path of the Mid-Atlantic/Coastal low.
Have shied away from the operational NAM solution, as it remains
an outlier when compared to ensemble data. It does appear that
precipitation will overspread the area Monday into early Tuesday.
It also looks like some colder air will be pulled into the area on
Monday still many questions as to how much and where.
Coastal low should move out to sea sometime Monday night or
The next system is expected to bring precipitation back to the
area on Wednesday.
The superblend will be used for the long term.
Temperatures through the extended will be above normal.
.AVIATION /09Z FRIDAY THROUGH TUESDAY/...
General VFR across ports with patchy MVFR fog will deteriorate to
MVFR in light rain and CIGs from 10-14Z across ports southwest
to northeast, as a negatively tilted shortwave lifts across the
region. A 5 to 7 hour period of IFR in rain and cigs is expected
with the shortwave passage into late afternoon, followed by slow
improvement later Friday night. Winds will be under 10 KTs
through Friday, being southeast overnight, becoming southwest
Restrictions are likely Saturday night into Monday with slow
moving low pressure.