Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 241254 AFDCTP Area Forecast Discussion National Weather Service State College PA 754 AM EST Sat Feb 24 2018 .SYNOPSIS... Periods of rain will continue through Sunday. The rain could be heavy at times tonight into early Sunday. A saturated ground and swollen streams will support an elevated risk for flooding through the weekend. A break in the wet weather pattern is expected early next week. Above average temperatures are expected to continue through much of next week before a relative cooling trend toward climatology into early March. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... *Flooding possible this weekend* Cool and damp conditions prevailing early this morning with widespread fog and areas of drizzle. Widespread dense fog covers much of the South Central Mountains and Lower Susq up to the Lycoming Valley. Dense Fog Advisory remains in effect through 14z from the South Central Mountains northeastward to the Lycoming Valley. Cooler air continues to work in from the west behind a cold front which crossed the central mountains after midnight. It remains to be seen how much mixing will take place in the dense fog area, but a good wind shift will push into the Laurels shortly and erode the warm sector (50s) which have lasted much of the overnight. Main focus for this weekend remains potential flooding with additional rainfall amounts of 1-2 inches for most of the area. Heaviest rainfall && .SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/... The focus this weekend will be on potential flooding with additional rainfall amounts of 1-2 inches forecast over most of the area. Steady rain expected to redevelop across central PA later this morning and afternoon as first wave crosses the area. Daytime rainfall should range from one quarter to one third of an inch amounts over the southeast to half to three quarter inch amounts (and locally 1 inch) across the northwest. The heaviest rainfall period/greatest risk for short- duration flooding should be tonight through early Sunday morning. Flood Watch includes all of Central Pennsylvania through Sunday evening. Forecast rainfall and very wet antecedent conditions (very saturated ground/soils and much above normal streamflow/swelling streams) will support an elevated risk for longer duration, widespread flooding of small streams, creeks and river tributaries. Expansive low lying/poor drainage flooding is also possible. Temperatures will slowly climb into the mid 40s to low 50s on today before peaking in the mid 50s and low 60s on Sunday based on multi model consensus blend. && .LONG TERM /MONDAY THROUGH FRIDAY/... The wet pattern looks like it will take a break during the first part of next week before precip risk increases next Wed-Fri. Model and ensemble guidance show a low pressure system tracking east-northeast from the TX/OK panhandle across the Central Plains/Midwest into the Great Lakes/Ohio Valley region by Thursday. The ECMWF/CMC solutions want to develop a secondary low to the south of PA from the southern Mid Atlantic piedmont to the coast while the GFS is much farther north with any secondary development. This may factor into some potential ptype issues or wintry wx but only something to watch at this range. Temperatures will continue to run above average next week with signs of trending cooler/closer to daily climate normals into early March. && .AVIATION /13Z SATURDAY THROUGH WEDNESDAY/... Dense fog has set up over the southern and central TAF sites with LIFR or lower cigs and vsbys at JST, UNV, IPT, MDT and LNS. BFD and AOO are at times in IFR and restrictions will only increase as the day continues. Precipitation is starting to spread from the southwest. These showers will continue to creep across the region by late Saturday morning, early Saturday afternoon west to east. the IFR or lower in cigs and vsbys through the central and eastern TAF sites will persist through Saturday. The dense fog will mix out with slightly improved vsbys late this morning. However this will not last long as the weather system moves in. Precipitation will further cause IFR cigs and vsbys as the rain will continue through the region through Saturday into Sunday. Along with this system is a LLJ with the LLWS between 05Z Sunday to 12Z. Upwards of a 50KT of shear should affect BFD, JST and AOO. Outlook... Sat...Widespread restrictions with rain. Sun...Widespread restrictions likely in periods of rain. Mon-Wed...No sig wx. && .HYDROLOGY... Active hydrologic pattern ramps up again Saturday through Sunday. Recent snow melt and rainfall has soils quite wet. Streamflows are also running high. Forecast additional rainfall of 1-2 inches (with locally higher amounts possible across the mtns of Western PA) will produce significant rises and will need to monitor levels closely. Some poor drainage and small stream flooding is likely. && .CTP WATCHES/WARNINGS/ADVISORIES... Flood Watch through Sunday evening for PAZ004>006-010>012- 017>019-024>028-033>037-041-042-045-046-049>053-056>059- 063>066. Dense Fog Advisory until 10 AM EST this morning for PAZ019- 026>028-035-036-042-045-046-049>053-056>059-063>066. && $$ SYNOPSIS...DeVoir/Lambert NEAR TERM...DeVoir/Lambert SHORT TERM...DeVoir/Lambert LONG TERM...Steinbugl AVIATION...Ceru/Gartner HYDROLOGY... is the U.S. government's official web portal to all federal, state and local government web resources and services.