Area Forecast Discussion
Issued by NWS State College, PA

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FXUS61 KCTP 242025
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
325 PM EST Fri Nov 24 2017

.SYNOPSIS...
High pressure will bring mainly clear skies and mild
temperatures to the region into tonight. A cold front will
bring some light rain showers on Saturday. This will be followed
by a shot of colder air, with scattered light snow showers over
parts of the Northwest Mountains and Laurel Highlands Saturday
night into Sunday. A prolonged period of mainly dry and
seasonably mild weather is then in store for much of next week.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
High pressure in control. Large-scale subsidence warming and
drying the low-levels with dewpoints dipping into the teens this
afternoon (being handled poorly by the RTMA/HRRR) with a little
assistance from full sunhine has also allowed temps to shoot up
several degrees warmer than anticipated, with highs topping out
in the upper 40s to mid 50s. Winds picking up just a bit over
western areas this afternoon as well, with gusts to around 15-20
mph becoming more frequent in the NW Mountains and Laurel
Highlands.

These winds will diminish somewhat this evening, but increasing
SW flow ahead of an approaching cold front will bring breezy
conditions back to the ridgetops of the west overnight as warm
air advection provides a mild night there as well. Lows across
the west will occur by midnight with steady or slowly rising
temps late with clouds beginning to thicken. Rain showers will
be approaching the NW Mtns by 12z. In the east, a more
traditional night in store with lighter winds and better
radiational cooling allowing temps to drop further and settle in
around 32F by sunrise.

Light rain showers will be nearing the NW Mountains by 12z Sat,
with best rain chances during the day on Sat.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/...
Light rain showers will be nearing the NW Mountains by 12z Sat,
with best rain chances during the day. Front is fairly weak and
not overly impressive, so only place I could muster likely pops
was in the NW mtns, and even there just looking at 0.10" or less
of QPF. Showers more scattered in the central mountains, and may
only see a sprinkle or even no rain at all in eastern sections
as front weakens even further as it progresses eastward. Temps
will be about 5F above normal over the east in the WAA ahead of
the front.

&&

.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
The pattern that has been in place will prevail into late
November.

Fast flow will bring small fast moving systems from the west
with some cold air from time to time, followed by warm periods
between cold periods. The tendency to have a ridge over the gulf
will limit moisture. Thus a few showers with the cold fronts and
limited snow showers in the cold air will be about it.

00Z models did support some snow showers across the far north
Sunday night and early Monday, but WPC charts and 12Z guidance
show fronts too far to the north. An example of this is that
there is no cloud cover this afternoon, until one gets into
Canada.

Thus I did back off snow showers across the north late Sunday
and early Monday.

Near record to record high temperatures fcst into the plains
early next week, this airmass heads toward our area, with plus
20 degree air at 850 mb to the west.

This will give us a mainly mild and dry week.

Some models last night showed a deep upper lvl low forming off
the southeast coast late next week, but models have a large
spread. I did back off superblend winds some for next Friday
night.

&&

.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
High pressure in control into tonight with widespread VFR
conditions and minimal clouds. Winds will be southwest at 6-10
kts across the central and western parts of the state this
afternoon with some gusts to 15-20 kts as SW flow increases.
Airfields throughout the Susq Valley will see winds remain light
this afternoon through tonight.

A moderately strong low-level jet will move over the NW half of
the state tonight creating a layer of LLWS based around 2 KFT
AGL as speeds increase to around 35-40kts. Surface winds over
that area will become light this evening, but pick back up to
around 10 kts overnight, higher on the ridgetops.

A weak cold front will bring scattered rain showers to mainly
western sections on Saturday, with MVFR restrictions becoming
likely by late morning over the NW Mountains, spreading to much
of the NW half of CWA in the afternoon.

Outlook...

Sat...Chance of rain showers mainly over NW half, changing to
snow showers Sat night. Cig restrictions likely NW half.

Sun...Chance of snow showers across the NW in the morning.
Otherwise no sig wx expected.

Mon-Wed...No sig wx.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$
SYNOPSIS...Ross/RXR
NEAR TERM...RXR
SHORT TERM...RXR
LONG TERM...Martin
AVIATION...RXR


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