Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 230623 AFDCTP Area Forecast Discussion National Weather Service State College PA 223 AM EDT Fri Sep 23 2016 .SYNOPSIS... There is a very low chance for an isolated shower to the north of I-80 this afternoon into early tonight. Fair weather with seasonably cooler temperatures is expected over the weekend. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... Clear skies will prevail for central and southeastern areas overnight...essentially a repeat of last night in terms of sky cover and local fog formation. Expect an increase in mid and high moisture over the northwest after midnight as decaying baroclinic zone approaches from the eastern GLAKS. Any light southerly wind and slight increase in surface dewpoints could keep nighttime lows a few degrees warmer across the board. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SATURDAY/... Recent warm spell should peak Friday ahead of approaching cold front. Model 850mb temps surging to arnd 16C should translate to max temps well into the the 80s over most of central Pa. Low level convergence along cold front, combined with some meager CAPEs, could support a few late day showers/storms across the northern tier counties. However, bulk of forcing assoc with parent shortwave is progged to pass north of the state, so will keep POPs in the slight chance category. Model RH time sections support a msunny forecast Friday over much of the area, although increasing clouds expected during the afternoon across the northern tier counties. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... All model data pushes cold front through central Pa Friday night with little in the way of upper level support or significant deep layer moisture. Thus, expect a mainly dry fropa for much of the area, with just a very low chance of light showers north of I-80. Although cooler air will begin flowing in on a northerly breeze, still anticipating another mild night overall with mins from arnd 50F over the northern mtns to around 60F in the south. If winds drop off to near calm across the north, could see some late night valley fog, while an active northerly breeze precludes fog issues elsewhere. Models remain in good agreement in dry and seasonable weather this weekend, as Canadian high pressure builds southeast into Pennsylvania. Some of the colder spots in north-central PA look to dip into the upper 30s Sunday morning, which is not unusual for this time of year. Forecast from Tuesday onward took a turn toward more uncertain overnight but extended models beginning to rally around the latest solution - albeit with a fair amount of variability. Large upper low in vicinity of western Great Lakes now looking to be a more significant player by midweek as ridge over western U.S. works eastward (rather than anchoring in place). This will edge the trough and slowly unwinding upper low into the Northeast behind an occluding cold front Monday, with the upper low impacting weather for much of next week. EC still a bit of an outlier with its deeper and more progressive trough, while the GFS camps the upper low over the region for several days. Thus, best forecast is to mention chances for showers Tue (mainly west) and Wed-Thu areawide with a return of slightly above normal temps. Broad SW flow on Tue will transition to NW flow by Thu as temps cool back down. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... High clouds continue to push southeast across the northern airspace in advance of frontal boundary located over Lake Ontario. Localized brief restrictions in fog remain possible around daybreak. Widespread VFR expected for most of the period with a very low chance for an isolated shower across the northern 1/3 airspace this afternoon into early tonight along the cold front. Guidance is indicating post-frontal sub-VFR ceilings reaching the northern airspace late tonight into early Saturday and have added MVFR FM group 24/03-05z at KBFD/KIPT/KUNV. Outlook... Sat-Sun...Patchy AM fog possible with mostly clear days. Mon-Tue...Increasing risk for showers/thunderstorms ahead of cold front. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Gartner NEAR TERM...DeVoir/Gartner SHORT TERM...Fitzgerald/Gartner LONG TERM...RXR AVIATION...Steinbugl

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