778 FXUS61 KCTP 100850 AFDCTP Area Forecast Discussion National Weather Service State College PA 450 AM EDT Wed Oct 10 2018 .SYNOPSIS... A strong ridge of high pressure will remain just off the mid Atlantic coast through tonight. A cold front will move through the area Thursday...with the remnants of Hurricane Michael tracking south of Pennsylvania. Cooler and drier conditions will arrive for Friday and the upcoming weekend. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Pre-dawn nighttime microphysics GOES enhancement shows stratus covering albut Warren County early today. This thanks to boundary layer flow advecting LLVL moisture from the ESE across central PA. Mostly thin cirrus is streaming ENE across portions of western and central PA. Where the stratus is most prominent, there could be patchy drizzle, mainly over my southeast counties early this morning. Chance of measurable precipitation is 10 percent or below. Morning clouds and areas of fog will burn off by around midday giving way to at least a partly sunny, warm and muggy afternoon, quite similar to Tuesday. Highs once again will range from the mid 70s to the lower 80s. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/... *Locally Heavy downpours and localized flooding possible Thursday. Thursday Shower chances begin to ramp up tonight as a surge in deep layer moisture arrives into southwest PA by this evening. 2.0" PW overspreads the Laurel Highlands and South Central mountains this evening and then lifts across the southeastern half of PA overnight. A cold front approaching the Commonwealth from the eastern GLAKS and Ohio Valley will provide more than enough forcing for several periods of showers and a few thunderstorms overnight and through the day on Thursday. Much of southeast portion of central PA remains in MRGL risk of excessive rainfall on Thursday as a result, with the main heavy rain impacts from the remnants of Michael staying south of PA. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... *Significant cool-down expected by Friday as a more typical fall weather pattern finally takes hold into next week Periods of locally heavy rain are likely on Thursday as a cold front crosses the Appalachians and interacts with tropical moisture from Michael. PW values are forecast to reach 1.5 to 2.0 inches which is well-above normal for early/mid October. Blend of NBM/WPC QPF yields 1-2 inches over the southeastern 1/3 of the CWA falling mainly in the 12-hr window ending 00Z Friday. Very soggy soils and swollen streams from relentless rainfall over the last several months will make this area susceptible to potential flooding concerns. The WPC D3 excessive rainfall outlook (ERO) places southeast PA in a marginal risk. The models are in general agreement in keeping the heaviest rains directly associated with Michael from the NC piedmont across southeast VA to the Delmarva Peninsula Thursday night into Friday. There is some uncertainty in the max QPF location and timing with at least some risk that it could track or shift farther north, but for now the most likely outcome is a southern track with the main impacts staying south/east of central PA. A significant pattern change is expected to follow in the wake of Michael as it accelerates away from the southern Mid Atlantic coast on Friday. The extended summer pattern will come to an end with all signs pointing toward noticeably cooler, more typical fall weather lasting into next week. After one of the warmest starts to October on record, the upcoming period of seasonably cooler weather with near to below average temperatures will feel rather chilly this weekend and next week. Parts of the northwest Alleghenies may see frost Sunday morning. Sub-zero air at 850mb crossing the lower lakes should result in rain showers (perhaps the seasons first flakes?) over the NW Allegheny Plateau and Fri-Sat. Model consensus shows the next rain-maker impacting the area early next week. && .AVIATION /09Z WEDNESDAY THROUGH SUNDAY/... VFR areawide this evening under influence of high pressure (centered off to our east). Expect to see a return of low clouds and areas of patchy fog overnight in anomolously high dewpoint air and southerly flow, with much of central PA becoming MVFR then IFR for several hours centered around sunrise. Could see development of some dense fog over the Susq Valley around this time as well. Restrictions expected to last through mid morning Wednesday. As like the past several days, conditions will improve by Wednesday PM. .Outlook... Thu...MVFR-IFR cigs/LLWS early becoming MVFR/VFR. Showers/isolated T-storms accompanying a cold front. Post- frontal low cigs developing northwest mtns Thursday night-Friday morning. Fri...MVFR cigs possible NW. Wind gusts 20-25kts from NW. Sat...MVFR cigs possible NW. Sun...No Sig Wx. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...DeVoir/Lambert NEAR TERM...DeVoir/Lambert SHORT TERM...DeVoir LONG TERM...Steinbugl AVIATION...RXR