Area Forecast Discussion
Issued by NWS State College, PA

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KCTP 160610 AFDCTP Area Forecast Discussion National Weather Service State College PA 110 AM EST Sat Dec 16 2017 .SYNOPSIS... A weak upper level disturbance will swing across the region this evening as a surface low forms over the Outer Banks and tracks out to sea. High pressure and a brief moderating trend in the temperature are expected by Sunday. A series of cold fronts will move across the area late Sunday into Wednesday. Windy and colder temperatures will follow. && .NEAR TERM /UNTIL 6 AM THIS MORNING/...
-- Changed Discussion --
Upper trof swinging east of the central mountains early this morning. Coupled WNW flow is driving transition to lake bands over northwest PA with several inches of accumulation expected through Saturday afternoon. The flow will favor a more westerly than NWLY direction suggesting the best snows will stay closer to the lake, mainly affecting NRN Warren and McKean counties. Lows in the teens and 20s will average about 3-6 deg colder than normal.
-- End Changed Discussion --
&& .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SUNDAY/... Lake effect snow showers will continue Saturday morning, tending to diminish during the afternoon as large scale subsidence begins to develop under rising heights aloft. It will still be colder than normal with highs ranging from the upper 20s northwest to around 40 over the south. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... This coming week will see the long-wave upper level trough that has been dominating out weather shift east as a deep trough digs over the Western U.S. Lake enhanced snow showers should be ending by Saturday night with the surface high pressure ridge moving off the coast and the winds becoming move west to southwesterly. The western trough kicks a strong shortwave out across the Plains Sunday into Monday. The associated low center will move northeast across the Great Lakes staying to our North and west. This system will bring in warmer air in southwest flow ahead of it. However, we may be cold air dammed near the surface so the +1 to -2C air at 850 hPa may not translate to a warm boundary layer. The warm advection should bring snow and snow to rain in the south but QPF amounts are light. Will have to watch for potential for some ice also Sunday night. We look to move into a fast moving pattern of weak shortwaves and chances for precipitation (mainly over the northern mountains) through the week. As a northern stream wave zips by to our north by Monday night, it should drag cold air back into the region Tuesday into Wednesday. The northwest flow triggers snow in relatively high POPS in NW PA due to LES. This cold surge should be relatively fleeting and high pressure and a potential surge of relatively warmer air follows Thursday. The warm advection and approaching cold front will likely produce increased potential for snow in NW Thursday into Friday. Farther south any precipitation would likely be mixed or rain. A strong frontal boundary will likely push another surge of cold air into the region Friday into Saturday as the eastern long wave trough tries to re-establish itself. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... * Cloud/Ceiling info for KBFD has been restored as of 00z * Expanding area of snow showers overspreading CentralPennsylvania late this evening. While most of the snow is producing MVFR restrictions, some of the heavier snow showers are producing IFR restrictions as they pass. Additionally, portions of southeastern areas have seen a brief area of clearing. This has resulted in spotty LIFR conditions. Most evident at KLNS at 03z, where visibility is down to 1/4 mile. Arctic fropa overnight will shift winds to the northwest, producing a more favorable over-lake trajectory. This will invigorate snow showers over the western and northern mountains. Result will be highly variable visibility conditions in the north and west as snow showers drift in and out. Outlook... Sat...Scattered snow showers and local restrictions NW/Laurels. Sun-Mon...Mainly VFR. Tue-Wed...mainly VFR, but possible restrictions in the western and northern mountains in snow showers. && .CTP WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
Winter Weather Advisory until 4 PM EST this afternoon for PAZ004-005.
-- End Changed Discussion --
&& $$ SYNOPSIS...La Corte NEAR TERM...DeVoir/Gartner SHORT TERM...La Corte LONG TERM...Watson AVIATION...Jung is the U.S. government's official web portal to all federal, state and local government web resources and services.