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Area Forecast Discussion (AFD)

Issued by State College, PA (CTP)

FXUS61 KCTP 240941

Area Forecast Discussion
National Weather Service State College PA
541 AM EDT Sun Mar 24 2019

An upper low over the Miss Valley will weaken as it pushes east
and merges with a shortwave diving southeast across 
Pennsylvania Monday. Canadian high pressure and associated dry
air mass will settle south across the area during midweek. A 
cold front is then likely to push southeast across the region 
next weekend.


Model soundings and upstream satellite imagery indicate 
gradually thickening high and mid level cloud cover today, as 
warm advection overspreads the region ahead of weakening upper 
low over the Miss Valley. Surface high will drift south of Pa, 
allowing a return wsw flow of milder, higher-pwat air into the 
region. However, large scale forcing with approaching system 
remains west of the state, so expect almost no chance of 
precipitation during the daylight hours. Model soundings 
indicate mixing to 850mb, where temps of 0-2C should translate 
to highs in the 50s over most of central Pa.


Northern stream shortwave and associated cold front is progged
to push southeast across the region tonight. Moisture return 
ahead of front is not that impressive overall, but best across 
southwest Pa. Thus, placed the highest POPs of around 60 pct 
across the Laurel Highlands, where orographic enhancement 

Have removed mention of accumulating snow across the northern 
mountains. Although soundings do become cold enough for snow 
showers up there after midnight, drier air will be arriving 
behind the front by that time, so will just carry the slight 
chance of a late night snow shower.

Remnants of Miss Valley upper low and associated surface low are
progged to track south of Pa on Monday. Latest guidance 
indicates the southern tier of the state could be clipped by a 
period of light rain during the afternoon or early evening. 
Surface ridging and much drier air mass over upstate NY should 
result in mostly sunny skies across northern Pa Monday, while 
overcast conditions look likely in the south. 


Med range guidance continues to support a high confidence of
fair weather during midweek, as Canadian high pressure drifts
southeast over the area. Both the 00Z ECENS and NAEFS show an
anomalous upper ridge building along the east coast late in the
week, with a slow-moving frontal boundary draped to our
northwest across the Grt Lks. Have introduced the chance of 
showers across northwest Pa late in the week to account for 
model differences with regard to how close this quasi-stationary
front gets to us. However, all guidance seems to suggest the 
best chance of showers comes next weekend, when east coast ridge
breaks down and cold front pushes across the state. Above 
normal temperatures appear very likely Fri-Sat in the deep 
southwest flow between east coast ridge and approaching front. 


VFR conditions across the region with clear skies. These
conditions are expected to continue overnight under the
influence of high pressure. Winds are now under 10 knots across
the region, and will remain so for the overnight.

Sunday will continue to feature VFR conditions across the
region, with just an increase in high clouds during the

A system approaching from the west will spread light 
precipitation across central Pennsylvania Sunday night into 
Monday. Across the north, a rain/snow mix is anticipated, with 
mainly rain in the south.

A frontal system will press southward during Monday, shunting
precipitation to the south by Monday afternoon.


Sun...No sig wx expected.

Mon...AM rain/snow. Restrictions possible, mainly northern and
western mountains.

Tue-Wed...No sig wx expected.

Thu...VFR, but with some scattered showers possible northwest




NEAR TERM...Fitzgerald
SHORT TERM...Fitzgerald
LONG TERM...Fitzgerald