Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 180834 AFDCTP Area Forecast Discussion National Weather Service State College PA 434 AM EDT Tue Oct 18 2016 .SYNOPSIS... Southwest flow ahead of a cold front will keep much above normal temperatures over the region right through midweek. Cooler air will follow the cold frontal passage Wednesday. Unsettled conditions will redevelop for the end of the week as a series of low pressure areas ripple up along the trailing cold front. Breezy and colder weather will move in for the weekend. && .NEAR TERM /THROUGH TONIGHT/... Temperatures are running some 15-25 deg warmer than normal as of 3AM. With the warm front off to our NE and the cold front still west of Chicago, another very warm day is in store with possible record setting warmth in several locations. See the Climo section below for some of the records. The cold front will be approaching the eastern Gr Lakes by nightfall which could threaten a shower into my NWRN zones before the day is over, but in most places it will be very warm and dry day. HRRR suggests we should easily mix to at least 850 supporting highs exceeding 70 over the north, and reaching at least the mid 80s over southern areas. With dewpoints nudging 60, it will even feel a little humid. The cold front will sag south overnight. Near term guidance is in good agreement with the front washing and the area of showers dwindling as it moves out of NWRN Pa down toward the coastal plain. With the increase in cloudcover, lows will likely be even warmer than tonight ranging from the mid 50s to mid 60s north to south. && .SHORT TERM /WEDNESDAY/... Wednesday will still be very mild with almost no push of cooler air behind the diffuse-dying cold front. A blend of models support the potential for a stray shower over western and southern areas. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... The trailing cold front is made to become the center of weather attention for Thursday and Friday as a storm system or a series of waves along the front organize over the southern Ohio Valley and slide up through central Pa. The exact track of the low will determine where the best rain will fall with a steady moderate to heavy rain expected along and just behind the front, and a more showery precipitation expected in the warm sector east of the front. Right now the GEFS/GFS and ECMWF all show a track through central Pa which would favor the NWRN half or so of my forecast area for an inch or more of rain. The upper trough will sharpen markedly as it drops through the eastern Gr Lakes and closes off over NY before tracking into New England and eastern Canada. A cooler blustery NW flow will develop in its wake with scattered showers, especially over the higher elevations of the west and north, a pattern we will see many times over the upcoming cold weather months. By Saturday morning it could be cold enough over the far NW for some wet snowflakes to mix with the rain showers. Saturday night into Sunday morning will be cooler still with a better chance of rain or wet snow showers. No accumulations are expected. For the last part of the weekend into early next week we should see colder and mainly dry west/northwest flow. Deterministic GFS differs from the ECMWF by showing a weak clipper type shortwave bringing a chance of precip back into northern Pa by Sunday night. The GEFS doesn`t support this. I used the blended MOS to arrive at a very small chance of showers, but confidence is low. && .AVIATION /08Z TUESDAY THROUGH SATURDAY/...
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Another morning of patchy dense fog impacting mainly portions of the Susq River Valley, especially KIPT/KSEG/KLNS where persistent IFR/LIFR conditions will continue until a few hours after sunrise. Elsewhere, any restrictions will be short-lived and around sunrise. Conditions return to VFR by mid morning (poss late morning at KIPT) as SW flow increases ahead of an approaching cold front. The remainder of the day will be VFR with winds picking up to around 10 mph (with gusts to 14-18 mph mainly across the west). As cold front nears this evening, showers and cig restrictions will work into the NW mtns. As front washes out over the central mtns heading into Wed, MVFR cig restrictions and a few stray showers will be poss - mainly the first half of the day. Unsettled weather will impact the area late week into the weekend. Outlook... Tonight...Reductions NW half with chance of showers. Wed...Reductions NW half and potentially into central mtns. Thu-Fri...Reductions likely areawide. Sct showers SE, period of rain elsewhere. Sat...Restrictions NW. Sct showers NW. Breezy.
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&& .CLIMATE... Daily record maximum temperatures are in jeopardy for 10/18. Here are the current records: Harrisburg: 82 in 1908 Williamsport: 82 in 1964 Altoona: 81 in 1998 Bradford: 75 in 1963 State College: 83 in 1938* *10/18 high will be officially recorded on 10/19 (7am-7am COOP) report so used 10/19 for record purposes. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ Synopsis...La Corte Near Term...La Corte Short Term...La Corte Long Term...La Corte Aviation...RXR Climate... is the U.S. government's official web portal to all federal, state and local government web resources and services.