Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 181955 AFDCTP Area Forecast Discussion National Weather Service State College PA 255 PM EST Sun Feb 18 2018 .SYNOPSIS...
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High pressure will move off the East Coast on Monday. An anomalous upper level ridge will build off the east coast this week...bringing a southwest flow of warm temperatures to the Keystone state for much of the week. A cold front will move into Pennsylvania on Wednesday...bring in cooler air for Thursday and Friday. A complex low moving northeast across the Great Lakes next weekend will bring more abnormally warm temperatures to the area next weekend. Much of the time will be dry...but wet conditions will be possible late Wednesday.
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&& .NEAR TERM /THROUGH TONIGHT/...
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Lots of melting going on as temperatures warm through the 30s and into the lower 40s from north to south this afternoon. Sfc high traverses the commonwealth this afternoon and pushes east of the region tonight. As the high passes off the Mid Atlantic coast tonight, and a warm front approaches from the Ohio Valley, southerly breeze will develop and prevent temps from dropping off much over the west. Across the east some decoupling and deeper snowpakc will allow readings to dip lower than guidance with lows 25-30 over my eastern counties.
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&& .SHORT TERM /MONDAY/... Rapid increase in deep layer moisture takes place Monday as channeled southwest flow advects higher rh into the region. Embedded southwest 850 mb jet and advancing warm front will focus best chance of rain over western sections, but eastern areas will be cloudy with spits of rain and drizzle developing Wedge of cooler air remains trapped east of the Appalachians. Highest POPS of 90 pct are painted across the northwest mountains, where best isentropic lift indicated at nose of low level jet. Southern portions of the Laurels and South Central Mountains may see late day improvement as the front lifts northward, but ageostrophic easterly flow likely to keep clouds in place. Western and southern areas will warm to near 50F Monday afternoon, while the east/northeast will remain mired in the low to mid 40s for highs. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
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All medium range guidance continues to show a building anomalous upper ridge along the east coast next week, with central PA breaking into the warm sector by Tue. 500 mb heights fcst to 596...not sure I have seen heights this high as this in Feb. Anyway...record high temps appear quite possible Tue/Wed. Hard to recall a pattern like this...with the upper level flow off the Gulf of Mexico. Mid shift had temperatures a little warmer than I had them yesterday. After looking things over...did up temperatures even more. Easy to see temps between 70-75F over much of the area both days...if not higher. A cold front will push through the region Wed PM...accompanied by a chance of showers. This boundary will likely stall just south of Pa before returning north as a warm front late in the week with a renewed chance of rain. Med range models do indicate there could be just enough low level cold air for the potential of some fzra Thu night or early Friday across northern Pa. Did not change much in this time frame...given how far out things are. Past this time frame...models show a low moving across the Great Lakes on Sunday. This would support another warm up. For day 7...the fcst is largely the superblend...with some minor adjustments.
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&& .AVIATION /20Z SUNDAY THROUGH FRIDAY/...
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High pressure will build east across Pennsylvania later today. Primarily VFR flying conditions expected through late tonight. Winds will be below 8 mph through tonight. High pressure will pass off the Mid Atlantic coast tonight as a warm front approaches from the Ohio Valley. A developing southerly breeze will bring LLWS in late, especially over the western portion. This will also aid in spreading stratocu restrictions in from the SW predawn Monday, with light rain and more widespread restrictions prevailing during the day Monday. Outlook... Mon...Restrictions return in light rain, especially northern half. Tue...Restrictions early east. Scattered rain showers and restrictions NW. Wed...Restrictions likely in rain showers, mainly NW half. Thu-Fri...Restrictions probable in rain showers.
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&& .HYDROLOGY...
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Unlike the event last Thursday evening...the flow is less west...east with the next system. Strong upper level ridging should push the warm front to the north faster. Thus QPF should be rather light across the area prior to 18Z Wed. Heaviest QPF prior to this time will be likely across northwestern Warren County Monday evening...with perhaps isolated amts in the .50 to .75 inch range.
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&& .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...DeVoir/Martin NEAR TERM...DeVoir SHORT TERM...DeVoir LONG TERM...Martin AVIATION...DeVoir/Martin/RXR HYDROLOGY...Martin

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