Area Forecast Discussion
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FXUS61 KPBZ 201511

Area Forecast Discussion
National Weather Service Pittsburgh PA
1011 AM EST Fri Jan 20 2017

Rain has returned to the region with a crossing trough of low
pressure. Mild weather will continue through the weekend.


With 10:15am update, primary changes were to timing of rain
showers as well as updating hourly temperature trends.

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 afternoon.

Temperatures will average well above average today.


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.


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
Tuesday morning.

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.


Expect widespread MVFR to IFR restrictions today as a crossing
disturbance spreads rain over the region. Precip will end by
evening across all areas, but IFR to low end MVFR cigs will linger
into Saturday.

Restrictions are likely Saturday night into Monday with slow moving
low pressure.




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