050 FXUS61 KCTP 281900 AFDCTPArea Forecast Discussion National Weather Service State College PA 300 PM EDT Sun Sep 28 2025
.SYNOPSIS... * Mostly sunny and very warm to close out the final Sunday of September; start of another extended dry spell. * Mild/warm start to the week before turning much cooler with stretch of dry weather continuing into October.
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.NEAR TERM /UNTIL 6 AM MONDAY MORNING/... Mostly sunny and warm afternoon day will lead to clear and mild night at any Cu crumble with sunset.
High pressure settling over central PA tonight will again favor radiational fog into early Monday morning.
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.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/... Monday and Tuesday also will be quite warm by end of September standards with fcst highs very close to/a few degrees cooler vs. Sunday. High pressure continues to dominate the pattern, setting up what should be an extended period of dry weather for the week.
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.LONG TERM /WEDNESDAY THROUGH SUNDAY/... 00Z guidance support an extended period of dry wx into early October, as the complex area of weather over the southeast not as likely to back northwest toward the coast now.
The main issue will be the potential for patchy frost across the north later in the week, especially Wednesday night. This based on a backdoor cold front dropping southward from eastern Canada, with shallow dry air working in from the northeast. This is normally how we can get cold, as lakes will not modify the airmass, as with the case with northerly or northwesterly flow. Got a small area of frost in the northern tier for Wednesday, Thursday, and Friday nights.
More information below.
October will start with 1030+mb Canadian high moves southeast from Hudson/James Bay into New England. This airmass change will drop daytime max temps by 5-10F day/day Wed & Thu and increase the risk of late night/early AM frost particularly in the northern tier where NBM min temps are fcst below 40 degrees.
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.AVIATION /18Z SUNDAY THROUGH FRIDAY/... Widespread VFR conds were found across central PA early Sunday afternoon beneath blue skies. Winds were generally westerly at 5 kts or less.
Skies should remain clear into tonight. We could see another round of fog develop during the pre-dawn hours on Monday, although it may not be quite as widespread as it was Sunday AM. Some high cloudiness should begin encroaching on the Lower Susq Valley by daybreak, which may lessen the chc of fog formation there.
Once any lingering fog dissipates Monday morning, we should be in for another day of widespread VFR conds late Monday morning through Monday afternoon. Winds will again be relatively light, generally less than 5 kts.
Outlook...
Tue...Patchy AM fog. Otherwise, predominantly VFR.
Wed-Fri...Predominantly VFR.
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.CTP WATCHES/WARNINGS/ADVISORIES... None.
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SYNOPSIS...Martin/Gartner NEAR TERM...Gartner SHORT TERM...Martin/Gartner/Tyburski LONG TERM...Martin/Tyburski AVIATION...Evanego
NWS CTP Office Area Forecast Discussion