Area Forecast Discussion
Issued by NWS State College, PA

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FXUS61 KCTP 162214

Area Forecast Discussion
National Weather Service State College PA
514 PM EST Mon Jan 16 2017

A warm frontal system will approach the region tonight and
Tuesday, followed by a cold front Tuesday night and early
Wednesday. High pressure will follow and bring mainly dry
conditions with temperatures several degrees above normal from the
middle of the week into the weekend.


Most significant radar returns early this evening are across the
NW Mtns, but very dry air at low levels resulting in just virga
in that part of the state based on surface obs and web cams.
Further south, developing WAA resulting in scattered showers
working into the Laurel Highlands at 2145Z. Near term guidance
supports chance/slight chance POPs early this evening across the
southern counties. Temps safely above freezing, so not
anticipating icing problems in that part of the state early this

As the warm air advection continues into the overnight, moisture
will similarly continue to increase with the chances for rain
ramping up the deeper into the evening we get.

The diffuse warm front will be advancing through the area tonight
complicating the temperature forecast as light rain invades the
region. Low temps will drop back to near or below freezing over
much of central and northern Pa where a Freezing Rain Advisory has
been hoisted. Southern areas will see temperatures get close and
near term trends will have to be monitored for the possibility of
expanding the icing forecast.

QPF will be light so amounts of ice are not expected to be
significant, but as we have seen several times in the past few
weeks, even a little ice on untreated surfaces can cause
significant problems.


Periods of rain will continue Tuesday morning as the warm front
advances north. By afternoon the cold front at the surface will be
entering my western zones while the upper thermal ridge will have
already progressed off to our east, leading to the rain becoming
more showery as thermal advection changes sign to negative.

Regardless, it`s not a terribly cold airmass upstream so Tuesday`s
highs are expected to be on the mild side, averaging about 5-10
deg above normal. Over my far SWRN and NWRN zones where the warm
air is expected to make a more aggressive push, highs will be
some 10-20 deg above normal.

I kept POPs rather high for Tuesday, but given the diffuse nature
of the warm front, precipitation is likely to be intermittent and
generally light in nature.


Winds turn westerly behind the system by Wednesday morning as
flow turns more zonal, but with no real cold air in sight, temps
will remain on the mild side and above freezing during the day.

Ridge re-establishes itself over the eastern U.S. for late in the
week, as mild SW flow persists over the midwest. Guidance
suggests energy will dive south along the west coast eventually
helping to strengthen the building upper ridge over the east.
We`ll be on the eastern side of this, so subtle shortwaves sliding
into the Midwest will bring varying amounts of cloudiness to the
west (less in the east) with low end chances for light showers.

Another wave approaches/lifts into the OH valley late next weekend
into next Monday. Again, temps could be marginal at the start
of pcpn overnight Sunday for some ice or snow, but the bulld of
pcpn looks to be rain at this point.


21Z TAFS sent.

Band of showers to the north, could see some precipitation aloft
earlier, as I was leaving to come to work.

Further to the west and south, more in the way of showers.

At the current time, temperatures are above freezing, but
dewpoints are low, and ground temperatures are still cold. Thus
still have the potential for freezing rain, especially on
untreated surfaces and cold objects.

Earlier discussion below.

MVFR ceilings remain over my SERN terminals a weak SSE low level
flow has kept the moisture locked in over the area.

Elsewhere ceilings generally above 5000` prevail as overall
cloudiness continues to increase from the west.

Restrictions are likely to develop/return during the evening with
widespread MVFR to LIFR conditions a good bet by late evening
through Tuesday as rain gradually spreads across the airspace.
There will be a risk for freezing rain, mainly over the northern
1/2 of the airspace between 05-15Z Tue.


Wed...MVFR/IFR west; MVFR central to VFR southeast. Rain showers
west ending Wed ngt.

Thu-Fri...No sig wx.

Sat...Sub-VFR developing with the approach of a warm front.


Freezing Rain Advisory from midnight tonight to 10 AM EST
Tuesday for PAZ004>006-010>012-017>019-037-041-042-045-046-


NEAR TERM...Fitzgerald/La Corte
LONG TERM...Lambert/Gartner
AVIATION...La Corte/Martin is the U.S. government's official web portal to all federal, state and local government web resources and services.