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 061520 AFDCTP Area Forecast Discussion National Weather Service State College PA 1020 AM EST Wed Dec 6 2017 .SYNOPSIS... Colder air is settling in as a pattern change is taking place. A prolonged period of mainly dry and chilly weather is in store into next week. && .NEAR TERM /UNTIL 8 PM THIS EVENING/...
-- Changed Discussion --
Updated the grids with latest data. Satellite imagery shows the main boundary is well to our east with one streak of high clouds over our southeastern areas. Thus it is quite sunny this morning and should be most of the day. More clouds over the Great Lakes and farther west with the weak short wave zipping across IN/OH which will enhance LES in the next forecast period. Biggest issue today will be some gusty winds when we mix. Winds will subside in evening east of the mountains faster than west. Chilly day relative to past few days.
-- End Changed Discussion --
&& .SHORT TERM /8 PM THIS EVENING THROUGH 6 PM THURSDAY/...
-- Changed Discussion --
LES should start up off Lake Erie. Put some light snow in the northwesternmost areas. But the CAM guidance flow and snow response is mainly in NY due to more west/southwest flow. The snow dearth in PA is in the HRRR and HREFV2. So most areas will be cold overnight with mostly clear skies. Another cold day on Thursday with snow/flurries mainly confined to higher terrain and extreme northwestern areas.
-- End Changed Discussion --
&& .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... Global model and ensemble guidance remains in very good agreement on the maintenance of high latitude blocking pattern featuring an amplified ridge-trough configuration over the West Coast and eastern NOAM. The primary forecast issues will be embedded shortwaves and associated surface waves/fronts, which due to their scale and fast mean flow aloft may be difficult to resolve until the short range time frame. There is high confidence in a prolonged period of below average temperatures into mid-December with a reinforcing shot of arctic air possible next week. The cold pattern will bring opportunities for snow; lake-effect is inevitable mid-late week but should remain focused along the Lake Erie shore into southwest NY given mean west-southwest low level trajectory. One or more clipper systems are probable and likely offer the best shot for light snow. Finally, there appears to be multiple waves of low pressure lifting north along a western Atlantic front from late week into the early weekend timeframe, with guidance varying on specifics. There is a possibility one of these waves could clip the eastern part of the area with some light snow, but right now the mostly likely outcome is for precip to stay east of the area or off the coast. A reinforcing shot of arctic air is looking more likely next week along with a more favorable northwest flow lake-effect pattern. The core of the winter cold should grip the area during the second week of December with some signs of moderation during week 3. && .AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
-- Changed Discussion --
Updated TAFS with latest observations and guidance. Only real issue is the winds and potential gusty winds. VFR should rule the day and night. Any snow showers would be near end of our TAF period and confined to northwestern PA and well north of the PA border for more understand lake effect snows. A little more in the way of cloud cover on Thursday into Friday, as winds aloft shift more to the west and even a little to the northwest. Airmass is rather dry and winds too much from the west-southwest for much response off the Great Lakes. Often the winds end up being more from the southwest than the models fcst, given the warm waters of the Great Lakes. Outlook... Thu-Sun...No sig wx expected.
-- End Changed Discussion --
&& .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Dangelo NEAR TERM...Grumm SHORT TERM...Grumm LONG TERM...Steinbugl AVIATION...Grumm/Martin

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.