Area Forecast Discussion
Issued by NWS State College, PA
Issued by NWS State College, PA
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116 FXUS61 KCTP 120300 AFDCTP Area Forecast Discussion National Weather Service State College PA 1100 PM EDT Sat May 11 2024 .SYNOPSIS... Upper level troughing will remain over Pennsylvania this weekend with a potent shortwave tracking over the state tonight into early Sunday. The upper trough will lift out early next week, then a cold front will likely push through Tuesday. A wave of low pressure is likely to track south of Pennsylvania next Wednesday. && .NEAR TERM /THROUGH SUNDAY/... Low pressure continues to move in from the NW, but not in a hurry. Short wave trough touched off numerous TSRA over wrn PA and they dropped across the srn tier and are into north-central MD at 02Z. A few lightning strikes left north of the border, but we`ve dropped mention of TS from the wx grids for the rest of the night. Un-concentrated forcing thru the rest of the night will keep the showers sct with breaks in between. As with last night, the breaks will allow fog to form, but there is a little more wind tonight than last (Fri) night. The low aloft and sfc will be coincident over the CWA in the morning/12Z. Thus, the moisture feed will still be lifting moisture into the eastern half of the area, and wrap-around moisture/flow under the upper low will keep the showers going over the N and far wrn mtns, too, into the morning. The best/biggest breaks will probably be the south- central mtns (Bedford, Fulton, Huntingdon, Franklin Counties, mainly). They won`t be clear all night, but will be the best place to see the Aurora tonight. But, they have just had rain, too, and will be almost sure to get fog form overnight. Sunday will be mainly cloudy for about the eastern 2/3rds to half of the CWA. Numerous SHRA are expected, mainly in the Susq Valley north of Harrisburg. But, likely PoPs are o/o for the morning with a taper to sct (30-50pct) coverage in the aftn as the upper heights rise. However, convergence still likely in the llvl flow and we can`t shake the SHRA totally before sunset. Maxes Sunday will be 65F S and 55F NE. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/... The upper low lifts out Sunday night and Monday with improving conditions for Monday, and temperatures moderating thanks to a milder southwest flow. A cold front trailing low pressure in eastern Canada is fcst to stall out over the lower Great Lakes Monday and will trigger some showers or a t-storm over the NW mtns Monday afternoon, but it appears most of Central PA should start the week rain-free. A wave of low pressure will approach from the Ohio Valley Tuesday before crossing the area Tuesday night, accompanied by a renewed chance of rain and perhaps some thunder. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... Lingering unsettled weather is possible into Wednesday, as upper-level low pressure passes overhead. Medium range models diverge a bit late next week. The 12z ECMWF shows unsettled weather persisting into Thursday, as the upper- level low pressure very slowly pulls to our east. The 12z GFS/GEFS is a bit more optimistic, showing an upper-level ridge bringing a period of dry weather from Wednesday night through early Friday. Both medium range models are in agreement in bringing our next weather maker into the area later Friday into Saturday with another round of showers and thunderstorms. && .AVIATION /03Z SUNDAY THROUGH THURSDAY/... At 03z, scattered rain showers (and perhaps a rumble of thunder near the Maryland state line) continue to drift eastward across central PA. Expect cigs to drop to IFR at BFD and JST overnight, as upsloping westerly flow develops. Farther to the east, the central mtns and Susq Valley are progged to see their cigs dip to MVFR overnight. Sunday will see northwesterly flow develop across the area, with gusts to 15 kts possible across the southern Alleghenies (JST, AOO). Cigs should slowly improve as the day progresses, with the slowest improvement expected across the western highlands. There could be a few diurnal rain showers by afternoon, esp across eastern PA. Outlook... Mon...Morning fog across the east/Susq Valley. Showers return across the north by aftn. Tue...Showers/tstms and reductions developing. Wed...Showery weather and reductions continue. Thu...Slow improvement, with a few lingering showers possible. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...DeVoir/Dangelo NEAR TERM...DeVoir/Dangelo SHORT TERM...DeVoir/Fitzgerald LONG TERM...Banghoff/Evanego AVIATION...Evanego