Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 241026 AFDCTP Area Forecast Discussion National Weather Service State College PA 626 AM EDT Tue May 24 2022 .SYNOPSIS... High pressure over New England will remain in place through the middle of this week. A cut off upper low will approach Pennsylvania late this week, then slowly lift across the region next weekend. The upper low is likely to exit the area by Memorial Day, as anomalous upper level ridging expands eastward from the Ohio Valley. && .NEAR TERM /THROUGH TONIGHT/... A weakening shortwave is progged to slowly shift east across Virginia later today, keeping the deepest moisture and associated shield of steady rain south of Pa. However, gradient between a weak surface low over North Carolina and strong high pressure across New England will result in a persistent east-southeast flow off of the Atlantic today. Model soundings indicate there may be sufficient moisture and orographic lift to support a bit of very light rain/drizzle over the southern tier today. Elsewhere, early sunshine over northern Pa will likely give way to increasing clouds by afternoon, as stratus creeps northward. Cloud cover and a flow off of the cool Atlantic should hold temperatures 5-10 degrees below average today over most of the region. However, GEFS 2m temp anomalies support near average temps over the northwest corner of the forecast area, where skies will be brighter. Model guidance indicates surface ridge will build south into Pa tonight, shifting the moist easterly flow south of the state and bringing clearing skies to most of central Pa. Breaking clouds, light winds and high relative humidity going into the evening will likely promote patchy late night valley fog. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY/... A building upper level ridge along the east coast should ensure mainly dry weather Wednesday and Thursday. However, a persistent low level southeast flow off of the Atlantic will maintain relatively cool conditions. Have undercut NBM max temps both days due to its warm bias in easterly flow/cold air damming scenarios. Model RH profiles support partly sunny skies for most of central Pa Wednesday, but upsloping stratus could potentially affect the Laurel Highlands and south-central mountains. As high pressure retreats off of the coast, increasing low level moisture advection is progged to result in stratus expanding northward over the area Wednesday night into Thursday, with even some patchy drizzle possible over parts of eastern Pa, where progged RH in the sfc-850mb layer nears 100pct. Scattered Thursday PM showers are possible over the Allegheny Plateau in vicinity of a slow-moving warm front over western Pa. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... 11 pm Monday update... On the large-scale, there is good agreement amongst our various ensemble prediction systems that an upper-level closed low will gradually fill and move eastward towards the Commonwealth later this week, leading to a high likelihood of showery conditions Thursday and Friday. Over the long holiday weekend, uncertainty grows, with more model disagreement creeping into the picture. The EC is among the most progressive and optimistic guidance sources, indicating that the aforementioned upper disturbance will move into the western Atlantic and be replaced locally by rising heights and improving weather. Meanwhile, the GEFS has a significant number of members showing the same system cutting off close to PA, signaling that unsettled weather could last much longer. For now, we saw no compelling reason to deviate substantially from the NBM, which shows gradual improvement on Saturday, then largely dry and seasonably warm weather Sunday and Monday. Hopefully, model consensus will improve as we approach Memorial Day weekend. && .AVIATION /12Z TUESDAY THROUGH SATURDAY/...
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Generally VFR at BFD,AOO, UNV, IPT, MDT, and LNS. MVFR cigs have already made it to JST as on 10Z. Ceilings expected to continue to bring all airfields to MVFR by midday and persist through the day on Tuesday. Light rain is possible along the southern tier Tuesday evening and night. A return to VFR is possible by early Wednesday morning, but may be delayed if low clouds are slow to move out. Outlook... Wed...MVFR cigs could persist due to continued easterly flow. Thu...Predominantly VFR, with brief restrictions possible in scattered SHRA/TSRA. Fri-Sat...Reductions likely in SHRA/TSRA as low pressure approaches from the Ohio Valley.
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&& .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Fitzgerald NEAR TERM...Fitzgerald SHORT TERM...Fitzgerald LONG TERM...Jurewicz AVIATION...Evanego/Gutierrez

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