Area Forecast Discussion
Issued by NWS State College, PA

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797 FXUS61 KCTP 212002 AFDCTP Area Forecast Discussion National Weather Service State College PA 302 PM EST Tue Nov 21 2017 .SYNOPSIS...
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Pennsylvania will remain under a mean upper level trough through the week, with a succession of shortwaves and accompanying cold fronts pushing southeast across the state.
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&& .NEAR TERM /THROUGH TONIGHT/...
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Warm daytime temperatures from the return flow and strong 850MB winds forming a low level jet will keep gusty winds across the region through the afternoon and early evening. The latest models have continued the warming trend with 12Z model soundings become well mixed through at least 850mb, so have increased daytime maxes by a few degrees accordingly. The latest CAMS show the mixing should continue until around 22 to 23Z. Latest satellite has bands of cirrus over the region. Mid to low level clouds will increase tonight as a cold front treks across the central Pennsylvania. There is a lack of a moisture with this system, however there remains impressive large scale forcing ahead of a potent mid level shortwave that should support a period of light rain beginning between 00Z to 03Z. That should change to snow across the northwest mountains after 06Z tonight. The GFS, NAM and EC all showing a band of 850-700mb fgen forcing within right jet entrance region, resulting in bulk of precip falling in colder air behind surface cold front. So even though latest models have around a tenth of an inch in moisture, it should be in the regions with the best forcing and colder air through the NW mtns. Given this, have increased QPF and snow amounts slightly. Expecting around an inch to an inch and a half through Warren and an inch through far western McKean.
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&& .SHORT TERM /WEDNESDAY/...
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As the front moves eastward through Pa early Wednesday the bands of rain/snow should diminish as it pushes southeast. The HREFV3 data supporting only slight chance of measurable precip southeast of the Allegheny Plateau. However, incipient secondary low off the Mid Atlantic coast could clip the southeast counties with a period of rain Wednesday morning. The brief period of lake effect snow showers Wed morning will end by mid to late Wednesday morning as the approach of high pressure and falling inversion heights should result in minimal accums early in the day across the western mountains. For most of central Pa, Wednesday should be dry and breezy with temps below normal. GEFS mean 8h temps between -4C and -9C should translate to highs from the low 30s across the high terrain of northwest Pa, to the upper 40s across Lancaster Co.
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&& .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... High confidence in fair/chilly weather Wed night and Thursday, when all model data tracks high pressure over the state. Return southwest flow ahead of an approaching cold front should bring fair and milder wx Friday. Relatively good agreement among med range guidance into next weekend, with cold front passage likely early Saturday. Scattered rain showers will likely to accompany the front Sat, followed by another period of lake effect snow showers Sat night into Sunday, as another blast of seasonably chilly air charges across the relatively mild waters of the Grt Lks. ECENS and GEFS both support below normal temperatures Sunday-Monday, as deep upper level trough swings over the northeast states. && .AVIATION /19Z TUESDAY THROUGH SUNDAY/...
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VFR will continue through the daytime as high pressure slides east of the Carolina coast. Gusty winds will continue through the daytime hours and will diminish between 22 to 00Z. Showers coming in from the west will bring down cigs and vsbys for a period between 03Z to 09Z behind frontal passage. There could be a brief period of rain just ahead of the front but will drop quickly to snow after 05Z. The main reductions will be at BFD and JST with improvements after 15Z. Outlook... Tue night-Wed...Rain/snow showers along and in the wake of a cold front. MVFR likely wrn 1/2. Thu-Fri...No sig wx expected. Sat...Chance of rain/snow showers.
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&& .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Fitzgerald NEAR TERM...Fitzgerald/Ceru SHORT TERM...Fitzgerald/Ceru LONG TERM...Fitzgerald AVIATION...Ceru/Gartner

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