282 FXUS61 KCTP 181132 AFDCTP Area Forecast Discussion National Weather Service State College PA 732 AM EDT Thu Aug 18 2022 .SYNOPSIS... High pressure continues to slowly build into the region. Temperatures will be very close to normals today under bright sunshine. Temperatures then trend slightly into the weekend. An upper level trough forming over the Upper Midwest will draw moisture from the south and bring rain back into the picture for the weekend and first part of the new week. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Fog widespread in the valleys this morning, and some of it around Renovo and Lock Haven may not be gone until 9 AM. Just one or two obs below 1/4sm. As we mix deeper, the moisture trapped near the sfc will lift and start to form cu, probably first on the higher hills over the nrn tier. Will keep PoPs unmentionable until early aftn when mdl soundings make CAPE in wrn Ny and nrn PA. Steep lapse rates will help them grow fairly tall again, but the upper low is pulling away which means that the coldest of the air aloft is moving away with it. Otherwise, plenty of sunshine once the fog is gone and before any cu thicken up. Temps will swing 25-30F thru the day to get very near normal maxes. && .SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/... Cu and showers will drop off pretty quickly this evening, and more clear sky is expected tonight. Fog will probably form again, but perhaps not as widespread since less of the area will pick up rain today vs Wed. Mins will be very close to Thurs AM. The cold spots of SEG and THV will likely stand out due to their local/micro climate. Friday should be a few degs warmer with plenty of sunshine. The high overhead will slide SE and build some over the East Coast. This should turn the wind out of the south and bring in slightly milder air. Just a tiny chc of a SHRA in the S, but capping should take care of that. Still hanging onto some very low PoPs for late Fri night, but mainly for the surge in moisture. The llvl inversion will probably keep it just clouds. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... Max POPs from latest NBM shifted to Sunday-Monday timeframe. Weekend warming trend cools down on Monday due to forecast clouds/rain. All medium range guidance supports a return to more humid and unsettled conditions this weekend into early next week, as a deep southwest flow develops ahead of a slow-moving upper trough approaching from the midwest. Model consensus tracks a lead shortwave over our region Saturday, with an associated weak surface low passing just south of the state. This feature should produce a chance of showers over central Pa, with even a period of steadier rain possible over the southeast counties, closest the surface low track. Scattered PM showers/tsra appear a good bet Sunday in high pwat air mass with falling heights and upper level diffluence ahead of upper trough. Latest ECENS and GEFS indicate the best chance of meaningful, widespread rain will be in the Monday PM to Tuesday timeframe, when large scale forcing peaks with passage of upper trough and plume of anomalous pwats along southwesterly low level jet. An early guess at possible rainfall early next week based on ensemble plumes is around a half inch areal average, with localized amounts of over an inch. && .AVIATION /12Z THURSDAY THROUGH MONDAY/... At 1130z, vivid dendritic pattern of widespread/locally dense valley fog was noted on Nighttime Microphysics channel and fresh vsbl pix, which will impact a few Central and Western PA TAF sites with LIFR/VLIFR for another hour or two early today. The fog will dissipate gradually between 12-14Z. Lingering fog/stratus clouds will burn off by 10 AM in most locations, followed by widespread VFR conditions. There is an outside chc of a late-day shower, but this activity should be much less widespread than what we've seen in recent days thanks to relatively as a result of limited instability with MU CAPE values generally several hundred J/KG or less (not enough to promote deep convection). Outlook... Fri...Patchy AM fog possible. Otherwise, VFR. Sat...Isolated PM SHRA possible. Otherwise, VFR. Sun-Mon...More widespread SHRA/TSRA and reductions possible. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Dangelo NEAR TERM...Dangelo SHORT TERM...Dangelo LONG TERM...Fitzgerald/Steinbugl/Gartner AVIATION...Lambert/Evanego