Area Forecast Discussion
Issued by NWS State College, PA

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743 FXUS61 KCTP 192052 AFDCTP Area Forecast Discussion National Weather Service State College PA 352 PM EST Fri Jan 19 2018 .SYNOPSIS... A large area of high pressure centered over the Lower Mississippi Valley will maintain fair skies for the next few days. Temperatures will climb above normal over the upcoming days with mainly dry weather continuing. A cold front will move through the area later Monday night and early Tuesday. && .NEAR TERM /THROUGH TONIGHT/... The high clouds over the east have become more patchy, leaving a bright day with filtered sunshine in most locations. Fair and milder conditions will continue as the upper ridge builds over the region. Highs will range from the lower 30s north to the mid 40s in the south. Overnight lows will average in the 20s. && .SHORT TERM /SATURDAY/... The latest ensemble MOS pops show a small chance of some light rain reaching my far NW counties around sunset Saturday. Otherwise more of the same is expected with a gradual increase in mid and high clouds throughout the day. Highs on Saturday will range from near 40F north to the lower 50s across the south. && .LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
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Another January thaw will bring a period of relatively mild weather to Central PA into early next week. Temperatures are not expected to be as warm as the previous thaw late last week, but departures should reach +10 to 15 degrees above average for mid to late January. The progressive pattern should keep the cool down through the middle part of next week rather brief before temperatures moderate/trend warmer into next weekend. A surge of warm advection ahead of a strengthening Mississippi Valley/Great Lakes cyclone will impinge on a retreating thermal gradient between I-80 and I-90. Forecast soundings indicate moisture will be rather shallow initially with areas of light rain confined mainly to the western and northern parts of the area. Elsewhere expect low clouds to develop with pockets of drizzle/mist and fog. Examination of thermal/moisture profiles specifically sfc temps and maxTw aloft suggest some patchy freezing drizzle is possible over parts of north-central PA Sat night and Sun night. The other concern may be black ice as snow melts during the day and then freezes at night. The risk of ice jam flooding will continue over the weekend and into early next week. See the hydro section for more details. The most likely period for widespread rain is Monday night into early Tuesday along/ahead of south-southwesterly LLJ axis and cold/occluded front. A secondary low may form in the lee of the Appalachians and support a period of enhanced rainfall over the eastern 1/2 of PA Tuesday morning. At this time, the total rainfall forecast for early next week does not appear to be as heavy as Jan. 11-12. Winds look rather blustery from later Tuesday into Wednesday on the backside of the low pressure system and may approach advisory criteria. Snow showers are likely downwind of Lake Erie into Wed night. Dry wx with moderating temperatures Thu-Fri.
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&& .AVIATION /19Z FRIDAY THROUGH WEDNESDAY/... Widespread VFR will continue into at least Saturday as high pressure maintains control of the local weather pattern. Outlook... Sun...Mainly VFR. Mon...Reduced conditions with rain showers associated with an approaching cold front. Tue...MVFR/IFR with snow showers west and north. MVFR/VFR central and eastern terminals. Wed...MVFR with snow showers west and north. VFR central and eastern terminals. && .HYDROLOGY... Main concern is watching water levels rise on Susq downstream on Harrisburg. Marietta gage /MRTP1/ continues its slow rise as ice builds up downstream. Gage above action stage and there is some minor flood concerns in Wrightsville ongoing. The Flood Watch for this area has been extended through the weekend, set to expire Monday afternoon. With milder temperatures there is potential for ice movement, as well as slow ice deterioration/thinning with time. All areas near rivers and streams that have significant ice buildup should monitor water levels closely for the next several days. && .CTP WATCHES/WARNINGS/ADVISORIES... Flood Watch through Monday afternoon for PAZ065-066. && $$ SYNOPSIS...La Corte NEAR TERM...La Corte SHORT TERM...La Corte LONG TERM...Steinbugl AVIATION...La Corte HYDROLOGY...Ross is the U.S. government's official web portal to all federal, state and local government web resources and services.