Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 280025 AFDCTP Area Forecast Discussion National Weather Service State College PA 725 PM EST Mon Feb 27 2017 .SYNOPSIS... Return flow around high pressure off the mid-Atlantic coast will bring milder air into the region through the middle of the week. Low pressure will move across the Ohio Valley and track north of Pennsylvania midweek, bringing a rainy period followed by a potent cold front late Wednesday. Much colder air is in store for late week, with sub-normal temperatures likely over the weekend. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... Still a few sprinkles traversing the Alleghnies this evening as a weak shortwave slides across the region. Areal coverage is shrinking as the precip conts to lift into drier air to the north. Will keep mention of very low pops for central and north central mtns ...which stand the best bet for seeing sct sprinkles overnight. Temps will remain about 10F above normals. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/... Low pressure deepening over the upper midwest Tuesday will push a warm front into the state bringing showers and perhaps a thunderstorm or two late day or Tue night. Overall, precip will be on the light side during this period. Temps on Tuesday will be another 10F higher than today thanks to the warm advection and morning sunshine - especially in the south. Readings climb back into the 50s north/60s south. A very mild night in store for Tue night as warmer air surges in from the SW ahead of a potent low pressure system - keeping lows in the 50s most locales. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... Severe thunderstorm risk is the primary focus on Wednesday with another strong cold front impinging on a convetive environment characterized by unseasonably warm temperatures, above normal PW, relatively low instability and very strong low-to-mid tropospheric winds. There is still some uncertainty in the details such as timing and whether CAPE can be realized due to preceding clouds/pcpn. Despite depicting clear potential for strong to severe storms given high shear/low cape scenario, there is still room for adjustments as models begin to converge on a consensus solution. The key message is preparation for what could evolve into another damaging thunderstorm wind event. The threat and risk information have been communicated through the HWO and social media/decision support channels with updates coming tomorrow morning with the Day 2 SPC outlook. It will turn noticeably colder Wednesday night into Thursday as strong NWLY post-frontal flow directs colder air into the area. Widespread 30-35 mph wind gusts are probable with 40+mph gusts possible on the Laurel ridges. The surge of CAA will bring snow showers downwind of Lake Erie into the NW Alleghenies/Laurels with minor accumulations (<1 inch) forecast Wed. night into Thursday morning. A broad trough remaining over the Northeast U.S. on Friday will push off the coast by the beginning of the weekend. A clipper system associated with the final piece of shortwave energy embedded in the trough may bring a mix of snow and rain Thursday night into Friday with a light accumulation possible. The mean 500mb flow is fcst to flatten out a bit over the weekend with temperatures moderating nicely to above average after bottoming out on Friday. Overall, the pattern looks fairly quiet over the weekend and into early next week with another strong frontal system possible by March 7-8. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... Weak shortwave sliding into the area from the west bringing just enough oomph to kick off very light rain and MVFR conditions across the southwest this afternoon. MVFR reductions may slip into KAOO-KUNV for a short time late today, with KBFD having a better chance for MVFR cigs tonight as light rain area drifts northward, though by then it will be weakening as wave slips by. First half of Tue will bring VFR conditions, with reductions working in from the west during the afternoon/evening as a warm front crosses the area bringing light rain. Outlook... Tue...Rain showers/Sub-VFR conditions developing from W to E. Wed...Rain showers/Sub-VFR reductions. Breezy. LLWS likely. Chance of thunderstorms. Wed night...Strong FROPA early with gusty winds/tstms. Thu-Fri...Sub-VFR likely west in sct snow showers. NW winds. Sat...No sig wx. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Dangelo/RXR NEAR TERM...DeVoir/RXR SHORT TERM...RXR LONG TERM...Steinbugl AVIATION...RXR is the U.S. government's official web portal to all federal, state and local government web resources and services.