Area Forecast Discussion
Issued by NWS State College, PA

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056 FXUS61 KCTP 232023 AFDCTP Area Forecast Discussion National Weather Service State College PA 423 PM EDT Thu Mar 23 2017 .SYNOPSIS... High pressure will drift off of the eastern seaboard tonight, allowing a warm front to lift into the region Friday. Patchy sleet and freezing rain is expected over central and northern areas from the early to late morning Friday before precipitation changes to all rain. The rain front will stall along the New York border, then oscillate in the vicinity of northern Pennsylvania through early next week...separating milder air to the south from cooler air and showers north. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
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Temperatures this afternoon are peaking mainly in the 40s with some mid-40 across central and southern Pennsylvania. A few cold spots in the northeast mountain may not quite reach 40. GOES-16 shows deeper clouds well to our west over Illinois so the first part of the night will be mostly clear with some very thin cirrus. Thus an initial rapid cool down before the clouds arrive. The clouds arrive just in time to trap some of the cold air but stop the cooling. The HRRR is showing slower arrival of the QPF than older larger scale guidance. But current model consensus brings a period of precipitation across the commonwealth after 8-10 UTC...a mixture of IP and ZR for many northwestern PA and some RA/FZRA in central areas...which has prompted Winter Weather Advisory issuance for the northern two thirds of central PA east of the Alleghenies. The southern tier may see isolated or patchy freezing rain...but confidence too low at this time for WSW issuance as per collaboration with LWX, PHI.
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Model consensus keeps threat of fzra between 08Z-15Z Friday...before changing to plain rain central and northeast. Expect less than one tenth of an inch of ice as QPF is light, but untreated roads could become slippery for morning rush. WAA lifts north of the region with 850mb baroclinic zone by midday Friday, indicating a dry and warmer afternoon across the area. Models indicate surface warm front will work into the central counties late in the day, pushing temps well into the 50s, while areas east of IPT and LNS will likely remain in the 40s.
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&& .LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/... At the outset of the longer term period the models are in fair agreement in timing and strength. All are indicating a boundary just to the north of Pennsylvania with a large upper level low moving through the central midwest. A negatively tilted ridge over the mid Atlantic will allow for stable but cloudy weather into Saturday. Lows Friday night into Saturday should range from the upper 40s to low 50s. There could be light rain showers on Saturday but warm and stable. A cooler moist boundary should move into the region Sunday out ahead of the approaching low. Have adjusted POPs for timing and intensity. QPF remains variable but possible wet period Sunday into Monday. Above average temperatures are expected over the weekend with the warmest day likely on Saturday with some sites approaching 70F over southern PA. Sunday should be markedly cooler behind a backdoor cold front and a likelihood of rain. However, above average temperatures (especially nighttime) appear very likely through early next week, as 12Z GEFS indicates Pa remains beneath a mean upper level ridge and plume of anomalous PWATs. The chance of showers will spike with passage of next shortwave Tuesday into Wednesday. && .AVIATION /20Z THURSDAY THROUGH TUESDAY/... Widespread VFR flying through the period. High to mid level clouds will increase tonight with surface winds veering to 90-160 degrees. Light precip will likely move across the airspace between 06-18z Friday, starting as RA/FZRA/PL before transitioning to all RA by 15z Friday. Added PROB30 group to hedge toward brief period of ice mix around daybreak Friday. Outlook... Fri...VFR/MVFR. Pcpn ending after 18z. Sat...Mainly VFR. Chance of rain northern 1/2 airspace. Sun-Tue...Sub-VFR with periods of rain. && .CLIMATE... Minimum temperature records for 3/23 at select sites: MDT: 14 in 1934 IPT: 8 in 1906 BFD: 5 in 1959 AOO: 15 in 1960 && .CTP WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory from 4 AM to 11 AM EDT Friday for PAZ006-012-019-026>028-037-041-042-045-046-049>053-056>059. && $$ SYNOPSIS...Fitzgerald NEAR TERM...DeVoir/Fitzgerald SHORT TERM...Grumm/DeVoir LONG TERM...Fitzgerald/Ceru AVIATION...DeVoir/Evanego CLIMATE... is the U.S. government's official web portal to all federal, state and local government web resources and services.