Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 162132 AFDCTP Area Forecast Discussion National Weather Service State College PA 532 PM EDT Sat Mar 16 2024 .SYNOPSIS... Unseasonably mild temperatures kicked off the weekend, but will gradually drop to below normal for the start of the upcoming week as a cold front pushes southeast across the state late tonight and early Sunday. The cold air will persist into the midweek period accompanied by a several bouts of snow showers over the Alleghenies and Laurel Highlands. Temperatures will warm up again during the latter half of the week ahead. && .NEAR TERM /UNTIL 7 PM THIS EVENING/... Surface ridging over Central PA combine with moderately deep vertical mixing up to around 5 KFT AGL has scattered out the earlier bkn-ovc stratocu deck across the Western Alleghenies with temps rebounding to the mid and upper 40s, while abundant sunshine and mild temps in the mid to upper 50s prevailed over the Central Ridge and Valley and Susquehanna Region. Little change is expected through dusk. && .SHORT TERM /7 PM THIS EVENING THROUGH 6 PM SUNDAY/... The left exit region of a 125 kT jet max and associated positive DPVA will accompany the passage of a cold front into the CWA tonight likely supporting a line of rain showers this evening. The rain will press from NW to SE thru the night, and break up across the Central and SE zones as the UVVEL associated with the aforementioned favorable exit region of the jet max races off to the east, leaving the region in broad deep layer subsidence beneath the left entrance region of the same jet core. Temps dip enough behind the front (and the DGZ descends into the upper part of the expanding stratocu deck acrs the Western Mtns) that anything lingering in he wake of it may mix with/turn to snow showers just as the flow becomes more lake- effect favorable. Rainfall will range from 1-2 tenths of an inch across the NW Mtns to between a few and several tenths of an inch over the Central Ridge and Valley Region and little or nothing across the Middle and Lower Susq Valley. Not much QPF being produced by most models after 12Z Sunday as a well-defined mid and upper level dry slot expands across the CWA, with the straight W-E llvl winds keeping most/all lake effect to our N. Subsidence also aids in drying things out, but clouds won`t go away Sun aftn/night. A gradual decrease in llvl temps will put the 8H temps down to -2C SE to -8C NW by late in the day Sunday. DOD/24 hour max temp drop will range from about 5 deg F across the Lower Susq Valley to nearly 15F cooler across the NW Mtns. && .LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/... -Winter weather through the first full day of Spring -Risk of locally heavy snow showers and snow squalls Sun-Tue -Coldest stretch of below average temps since mid-January Despite plenty of signs of early Spring thanks to one of the warmest winter seasons and first 15 days of March on record, the first official week of Spring 2024 will begin on the cold side with frequent snow showers downwind of Lake Erie and over the Allegheny Plateau. There will also be the potential for localized snow squalls through early week along with late season lake enhanced and orographic snow accumulation in the favored snowbelts and higher terrain. Several reinforcing shots of cold air will maintain one of the longest stretches (3-5 days) of below climo temperatures since mid-January. That speaks to how mild it has been over the last few months. Ensemble data shows some moderation by late week with max precip probs shaded toward southeast PA by the weekend. && .AVIATION /22Z SATURDAY THROUGH THURSDAY/...
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A few flat cu persist over Central PA heading into the early evening hours, and a southwesterly breeze continues to occasionally gust 15-25 kts. Clouds will begin to increase from the northwest this evening, as a cold front approaches. Rain showers are expected to develop across the western highlands after sunset and spread southeastward. Additionally, a several hour period of LLWS is expected overnight due to a 35-45 kt southwesterly jet passing overhead a couple thousand feet off the sfc. The rain showers will tend to dissipate as they progress southeastward across the remainder of Central PA overnight, and may not reach the Lower Susq Valley. Low-end MVFR cigs will develop over the western highlands (BFD, JST) overnight, and borderline VFR/MVFR cigs should spill into the central mtns (AOO, UNV, IPT). The Lower Susq Valley (MDT, LNS) should remain VFR. On Sunday, the front will pull away from the area with chillier air arriving on an increasingly blustery northwesterly wind. Lingering MVFR cigs and perhaps a few -SHRASN are expected across the western highlands, with VFR conds expected elsewhere. Outlook... Sun night-Thurs...Periodic snow showers and reductions, primarily across N/W PA. This will be enhanced by reinforcing shots of chilly air and gusty W/NW winds.
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&& .CLIMATE... Astronomical Spring (vernal equinox) begins on Tuesday March 19 at 11:06 PM EDT. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Lambert NEAR TERM...Lambert SHORT TERM...Lambert LONG TERM...Steinbugl AVIATION...Lambert/Evanego CLIMATE...Steinbugl

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