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Area forecast discussion 
National Weather Service Pittsburgh PA
152 am EDT sun Oct 23 2016

a quick moving low pressure will bring rain showers mostly north
of Pennsylvania and Ohio turnpikes Sunday night. Dry weather
returns through mid week, however daytime highs will be in the
50s...which is below normal for this time of year.


Near term /through tonight/...
winds have backed to west or southwesterly this morning, allowing
for modest warm advection to take place. This warming is currently
competing against wind-inhibited radiational cooling, and the
result is near steady temperatures. Further upstream, surface
temperatures are holding in the upper 40s. Consensus of near term
guidance shows temperatures creeping upwards through sunrise,
which seems viable.

After daybreak, strong southwesterly flow and insolation will
allow temperatures to warm rather quickly. Highs Sunday should
reach low 60s by afternoon, mid to upper 50s in the high terrain
and across the north.

Late tonight, cloud cover will increase across the north as a
clipper system streams in from the west. This system will
accelerate as it approaches, ultimately getting absorbed by the
large filling low residing north of Maine. Rain will initially
hold off until after sunset tonight, but will quickly spread to
areas north of I-80 and eventually into the ridges overnight into
Monday morning. Temperatures will remain warm enough to preclude
any mention of snow. Gusty southwesterly winds will continue
overnight as a strong low-level jet streak will accompany the
passage of the low.


Short term /Monday through Tuesday night/...
cool northwest flow will re-establish in the wake of the clipper
and associated cold front. Can't completely rule out lake-enhanced
showers across the north Monday, as the cooler air moves over the
relatively Warm Lake Erie waters. Any lingering showers that do
exist Monday afternoon should diminish quickly Monday night as
drier air filters in with the surface high encroaching from the

High pressure at the surface will then keep the forecast area dry
through at least early Wednesday. Persistent northwest flow aloft
will bring 850mb temperatures back below 0c through the short
terms, which will aid in keeping surface temperatures below
average through the middle of the week.


Long term /Wednesday through Saturday/...
the next significant weather will be with a fairly-strong
shortwave and surface low pressure moving across the Great Lakes
later Wednesday night into Thursday. Likely pops were included for
this system until it shifts east to New England later Thursday
night. Another cold front will approach by Saturday, bringing
shower chances back to the forecast. Temperatures will be near or
just below the seasonal averages through the period.


Aviation /05z Sunday through Thursday/...
high confidence forecast. Area of altocu will advect over the
region through the morning hours before vacating. High clouds then
take over until moisture increases ahead of the next low pressure
system. Clouds will be MVFR after 03z Monday at fkl and duj with
vcsh. Visibilities also shall fall into the MVFR category if the
aforementioned airports experience a shower. There is still
question how scattered showers will be at other terminals. It
does not appear mgw or zzv will see any restrictions due to

Winds shall stay around 7-11kts from the SW then veer to the west
around daybreak. Gusts up to 20 kts are possible during the 16-20z
time period. Low level wind shear continues to be highlighted by
several high resolution models after 0z Monday. If the trend
continues this will need to be inserted into the forecast.

Outlook /Sunday night through Thursday/...
Sunday night / Monday...MVFR possible with showers. Low level wind shear also
Tuesday - Wednesday...VFR
Thursday...MVFR with rain showers likely


Pbz watches/warnings/advisories...



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