Area Forecast Discussion
Issued by NWS State College, PA

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492 FXUS61 KCTP 011558 AFDCTP Area Forecast Discussion National Weather Service State College PA 1158 AM EDT Sat Oct 1 2016 .SYNOPSIS... A cut off upper low over the Ohio Valley will keep deep-moist southerly flow over the region through the remainder of the weekend. A ridge of high pressure will build east into Pennsylvania behind this system early next week and will likely remain over the area through the middle, and perhaps end of the work week. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Radar and satellite show clouds and showers feeding northward around the upper low along the Indiana-Ohio border. This will remain the story into Sunday before the upper low finally begins a slow trek down the St. Lawrence River valley. So for today we can expect a continuation of the periods of rain and drizzle with the occasional heavier shower mixed in for good measure. Rainfall will average a tenth of an inch or less, however locations seeing heavier showers could pick up 3-4 tenths of rainfall in just a 15 to 30 minute period. Blended model guidance (NBM) once again appears too warm and unable to adequately handle the shallow/cool easterly low level flow and clouds that will stay trapped in the ridge and valley region and across the nrn mtns for much of the day. Will keep forecast max temps nudged closer to the cooler guidance with highs this afternoon only making it to the upper 50s across the mountains and lower to mid 60s elsewhere. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SUNDAY/... Skies will stay mostly cloudy to cloudy tonight (mainly in the form of stratus) as a near sfc easterly flow persists. Isolated to scattered showers (and some patchy drizzle along the eastern slopes and ridge tops will occur as one disturbance aloft exits to the northeast of the region, and another upper 90-95 kt jetlet moves into western PA early Sunday morning. Rainfall amounts will be generally a few hundredths of an inch at best in most places...with around one tenth possible in a few locations. Similar low temps are anticipated tonight - in the lower 50s across the northern and western high terrain, and mid to upper 50s in the central and southern valleys. && .LONG TERM /SUNDAY THROUGH FRIDAY/... Latest operational models track the persistent and slow-moving cut-off low to near Detroit at 12z Sunday, before it finally begins to turn east and gradually fills in as it gets picked up in the longwave flow and tracks across NY state Monday. The results on the forecast will be a continuation of showery weather through the second half of the weekend, though with just light amounts. Followed by a slight chance for showers across the north early next week along with cold air advection filtering into the region early next week. Surface high pushing the cooler air our way slides off the New England coast midweek, but persistent easterly flow feeding into the Mid-Atlantic region should keep plenty of clouds around along with at least a chance for light showers/drizzle across southern half of CWA through midweek. Latest on Hurricane Matthew in the 00z runs - Tremendous differences have developed between the ominous GFS and the much more benign forecast by the latest EC for the U.S. main-land. The 00Z GFS brings a potent Matthew across the Western Bahamas then has it paralleling the SE U.S. and Carolina coast late in the week...before projecting it to get captured by a deepening upper trough and accelerating north into Long Island next Sat/Sat night. GEFS has roughly the same track, but as expected becomes more diffuse through time with the location and intensity of the storm`s center just off the East Coast. The 30/12z operational ECMWF parked the storm over or just to the north of the Bahamas for a prolonged period during the middle to latter part of the upcoming week, which was a low confidence solution. The latest 01/00Z run of the EC now carries the hurricane well to the northeast of the Bahamas Friday and on a steady course to the Northeast toward Bermuda by the middle of next weekend. With such drastic differences between the GFS/GEFS and the EC 5-7 days out, we`ll continue to play the middle of the road and note just scattered showers with the passage of a more definitive northern stream shortwave and sfc cold front late next week or early next weekend. Temperatures will be slightly below normal through the latter half of the weekend, before shifting to slightly above normal by the middle of next week...then possibly dipping back to near normal as clouds (at least the mid and high variety) thicken-up to the NW of Matthew. && .AVIATION /16Z SATURDAY THROUGH WEDNESDAY/... Widespread IFR conditions will continue into tonight with periods of rain, drizzle and fog. Gradual improvement to MVFR/VFR is projected by later Sunday into next week as the upper low finally begins to pull away from the region. Outlook... Sun...IFR trending to MVFR/VFR late. Scattered showers continuing. Mon-Tue...Gradual improvement likely. Wed...Mainly VFR. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...La Corte/Lambert NEAR TERM...La Corte/Lambert SHORT TERM...Lambert LONG TERM...Lambert/RXR AVIATION...La Corte/Steinbugl

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