Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 190847 AFDCTP Area Forecast Discussion National Weather Service State College PA 447 AM EDT Tue Mar 19 2024 .SYNOPSIS...
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A weather season mismatch across central PA this week with a brisk and chilly winter-like pattern bringing rounds of snow showers for the first few days of Spring. Temperatures should bottom Thursday night and trend seasonably warmer over the weekend and into next week. A period of rain (or wet snow at higher elevations) is likely Friday night into Saturday morning.
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&& .NEAR TERM /THROUGH TONIGHT/...
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Expect ongoing CAA/lake effect snow showers and flurries to continue to fade/dwindle this morning as the llvl wind trajectory backs or shifts from the NW to SW in advance of a clipper low pivoting eastward just north of Lake Superior. Most of the higher terrain in the western and northern Alleghenies should wake up to a fresh coating of snow. As the lake effect connection tapers off, low-mid lvl warm advection and isentropic lift should generate some light snow developing across the northern tier based on the latest hires ensemble guidance. WPC/NBM qpf amounts favor <1 inch along and to the north of US-6. The brief shift in the llvl wind trajectory to a WAA regime will help temperatures trend higher by as much as 10 degrees day/day over the Laurel Highlands. Despite the neutral to positive 24hr maxTchange, fcst highs ranging from the mid 30s in the northern tier to mid 40s in the lower Susquehanna Valley are still 5 to 10 degree below daily climo. Snow showers are most likely to linger over the western Alleghenies tonight into AM Wed. as a progressively colder westerly flow ramps up into Wednesday morning. Cloud cover and active breeze will hold temps in the 30s tonight across the majority of the area or about +5F above climo give or take.
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&& .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
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-A winter-like pattern for the first full day of Spring 2024- The passage of the cold front trailing the aforementioned clipper low early Wednesday should be accompanied by scattered rain/snow showers. A few of the showers could survive into the Susq Valley, due to strong forcing ahead of the upper level shortwave. Steep lower tropospheric lapse rates indicate the potential of some heavier snow squalls across the north central mtns and we added chance SW+ to the wx grids. The snow squall parameter fcst from CIPS deterministic models is also generally supportive of a squall risk Wednesday with timing and marginal air/road temps suggesting sharp visby reductions as the primary impact. We continue to highlight the snsq threat in the HWO. Deep cold advection and passage of an isallobaric/pressure rise couplet signal the strongest northwest wind gusts Wednesday afternoon/evening. Peak bufkit mtum transfer and ensemble data indicate peak gusts 35-45 mph range or just shy of advisory criteria. The cold NW flow continues into Thursday with snow showers and flurries downwind of Lake Erie and over the Alleghenies gradually diminishing by Thursday night as high pressure builds into the area. Temps likely bottom on Thursday with daytime highs 10 to 20F below average and what could be the coldest night until next winter (teens and 20s).
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&& .LONG TERM /FRIDAY THROUGH MONDAY/...
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Medium range guidance suggests a period of light precipitation is likely Friday PM associated with warm advection ahead of a weak northern stream shortwave. Thermal profiles point to mainly rain, but the N Mtns could be cold enough for a light snow accumulation. Most guidance keeps a more significant southern stream shortwave well south of the area. However, there remains a small chance of phasing of two branches of the jet, resulting a heavier rainfall across Eastern PA Friday night into Sat. Fair and cool weather looks likely the second half of next weekend, as upper troughing exits the east coast and high pressure builds in from the Grt Lks. Rising heights noted in the model guidance early next week, but a cold air damming signature with strong high pressure over the Canadian Maritimes suggests the warmup will be tempered.
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&& .AVIATION /08Z TUESDAY THROUGH SATURDAY/... There will be occasional to persistent MVFR across PA`s northern and western mtn airfields tonight and even some brief periods of MVFR Cigs at KUNV and KAOO in -SHSN this into this evening. These snow showers are currently marching their way SE as the overhead trough moves through. Lake effect snow behind it will continue to impact BFD into the early morning hours. West-northwest winds will be moderately gusty this evening and tonight for all TAF sites. A dual or multi-layered cloud shield (mainly VFR) will spread across the region Tuesday as the low level flow backs a bit more to the west-southwest, helping to confine most of the snow showers across the far NW zones, with generally mostly cloudy skies and breezy and dry conditions elsewhere. Outlook... Tuesday-Saturday...Periodic snow showers and reductions, primarily across the higher terrain of northern and western PA. This will be enhanced by reinforcing shots of unseasonably cold air and gusty W/NW winds. West to northwest wind gusts could peak in the 35 to 40 mph range on Wednesday. && .CLIMATE...
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Astronomical Spring (vernal equinox) begins today at 11:06 PM EDT.
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&& .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Steinbugl NEAR TERM...Fitzgerald/Steinbugl SHORT TERM...Fitzgerald/Steinbugl LONG TERM...Fitzgerald AVIATION...Lambert/Bowen CLIMATE...Steinbugl

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