Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 191218 AFDCTP Area Forecast Discussion National Weather Service State College PA 718 AM EST Sun Feb 19 2017 .SYNOPSIS... An extended period of mild, spring-like weather with well above normal temperatures is expected through the end of the upcoming week. A weak cool front will push through the state late Tuesday and Tuesday night, accompanied by a few periods of mainly light showers. A better chance for showers will come Friday into Saturday as a strong cold front pushes east from the Ohio Valley. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... The northern edge of higher PWAT air around 0.75 of an inch will slide across the southern tier counties of PA through the mid morning hours. the northern edge of a stratus/stratocu deck based between 1000-1500 ft AGL will coincide with this northern limit of higher PWAT air, and will be topped by some altocu and cirrus. Across central and northern part of the CWA mainly clear skies at 0930Z will be followed by periods of cirrus clouds as a shortwave aloft moves from the glakes region to southern New England today, and pushes a backdoor cold front into central and NERN PA late today and tonight. 850 mb temps cool by as much as 7C over the far NE corner of the state, and 3-4C elsewhere along and to the east of the RT 322 corridor. Temps to start the day today will range from the upper 30s to lower 40s across much of northern PA, to the mid 50s across the far SE where the most and thickest cloud cover will prevail. GEFS mean 850mb temps will be about 2-4C cooler than Saturday, which will lead to maxes from around 50F over the northern tier, to the low and mid 60s in the southern valleys. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/... The backdoor cold front (and shallow cold air to its east) should back wwd and bank up against the Allegheny Front late tonight and Monday. Shallow stratus are likely across roughly the NE half of PA early Monday, but should mix out in most places by late Monday morning as the cooler air will be very shallow and lack a significant easterly upslope component. A mostly sunny late morning and afternoon Monday will combine with 850 mb temps of 1-3C across much of the region to yield max temps in the lower 50s. Readings will reach the mid 50s over the SW part of our CWA, but only make it to around 40F across the highest terrain of Sullivan County in the far NW where 850 mb temps will stay around 0C for much of the day. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... Gradually milder temperatures will return for the extended period as no genuine cold air push is in sight. High temperatures in general will be 10 to 20 degrees above normal with min temperatures mainly above freezing. The rather strong sfc ridge slides to the Mid Atlantic/Southern New England Coast on Tuesday, followed by a weak cold frontal boundary and a brief period or two of showers for late Tuesday (West) and over the Central and Eastern parts of PA Tuesday night into the mid morning hours of Wednesday. Clouds associated with this weak frontal boundary will help to suppress temps a bit (but they`ll still remain well above average). The flow turns back to the SW by Wednesday causing temps to rebound. The overall, large-scale pattern becomes more amplified late in the week as a system over the central plains deepens and lifts into the Great Lakes. Clouds will increase Thursday and Friday with warm front lifting through, and bringing increasing rain chances heading into the weekend. && .AVIATION /12Z SUNDAY THROUGH THURSDAY/... 19/12z: IR satellite loop shows rapid expansion of low stratus envelope since 06z across the OH Valley into SW PA via moist upslope low level flow. HRRRX seems to have a decent handle on the low cigs impacting KJST/KAOO thru 14-16z. A period of IFR is mostly likely at KJST. Expect improving conditions by afternoon. Surface wind gusts up to 20kts from 260-290 degrees from mid morning through the afternoon. Backdoor cold front may bring some lower cigs into the northeast 1/2 of the airspace after midnight into early Monday morning with best chance for MVFR cigs at KIPT. Outlook... Mon...VFR/No sig wx. Tue-Thu...Sub-VFR psbl with chance of rain. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Lambert NEAR TERM...Lambert SHORT TERM...Lambert LONG TERM...Lambert/RXR AVIATION...Steinbugl is the U.S. government's official web portal to all federal, state and local government web resources and services.