Area Forecast Discussion
Issued by NWS State College, PA
Issued by NWS State College, PA
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673 FXUS61 KCTP 240817 AFDCTP Area Forecast Discussion National Weather Service State College PA 417 AM EDT Mon Jun 24 2024 .SYNOPSIS... An upper level trough will swing over Pennsylvania today, then high pressure will build over the state tonight. A relatively zonal flow will remain in place through the rest of the week, with cold front passages likely late Wednesday and either late Saturday or early Sunday next weekend. && .NEAR TERM /UNTIL 8 AM THIS MORNING/... Early morning satellite imagery shows breaking clouds downwind of the mountains, as a drier northwest flow overspreads the state behind last evening`s cold front passage. However, low level moisture ascending the Alleghenies will continue to produce sct-bkn stratocu across the the northern and western part of the forecast area. Low level cold advection will push readings steadily downward this morning, with daybreak readings likely ranging from the mid to upper 50s over the N Mtns, to around 70F across the Lower Susq Valley. && .SHORT TERM /8 AM THIS MORNING THROUGH WEDNESDAY/... The arrival of the upper trough will bring markedly cooler weather to the region today, with 800mb temps supporting highs from just the lower 70s over the mountains north of KIPT, to the mid 80s across the Lower Susq Valley. Low level instability associated with the passage of the upper trough should result in a considerable amount of cu/stratocu today over the N Mtns, where a stray shower is possible. A tight pressure gradient and steep lower tropospheric lapse rates should result in breezy conditions by late June standards. Latest Bukfit soundings support afternoon wind gusts of 20-25kts over the western part of the forecast area and 25-30kts in the east, which is several knots higher than NBM guidance. The arrival of very dry air aloft above a weak inversion a signal that reliably results in afternoon dewpoints dropping below NBM guidance, so have leaned toward the drier MAV guidance. Fair and seasonable weather with diminishing winds are anticipated tonight, as high pressure builds into the state. Latest NAMNest and SREF prob charts target the Alleghenies for late night valley fog. The surface high is progged to pass off of the Mid Atlantic coast Tuesday, resulting in a warmer return southwest flow. Ensemble mean 850mb temps rising to near 17C supports highs mostly in the 80s, to near 90F in the Lower Susq Valley. However, dewpoints remain moderate in the 50s. A warm front lifting through the Eastern Grt Lks may result in a shower or tsra Tuesday night, mainly over the NW Mtns. Surging PWATs and falling heights ahead of an upstream cold front will bring a much better chance of widespread showers/tsra Wednesday afternoon. A ribbon of relatively strong mid level winds, combined moderate instability, suggests organized convection and locally severe weather is possible Wed PM. Latest ensemble plumes indicates most likely aerial average rainfall Wed will be around a half inch. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... Late evening update holds very minor changes to the long range fcst. Did knock out PoPs totally from Thurs-Fri as we dry nicely behind the mid-week front. Before the front, Wed could be just muggy and hot enough to need a heat advy in the SE, but only for Wed. Prev... Showers and storms will gradually exit to the the southeast on Wednesday night as high pressure builds in. The midweek cold front will reset the cycle similar to what today`s cold front will do and usher in a similar stretch as Monday & Tuesday. Thursday and Friday will consist of about 48 hours of lower dewpoints, temperatures closer to average for this time of year, and plenty of sunshine. Afternoon highs in the 70s and 80s, overnight lows in the 50s and 60s (perhaps even upper 40s in the northern mountains Friday morning), and dewpoints below 60F will feel especially good with the persistent stretch of heat. As high pressure shifts to the east on Friday, southerly flow will support increasing temperatures and moisture into the weekend. The chance for showers and storms will also ramp up Saturday and Sunday as a warm front lifts across the region. && .AVIATION /08Z MONDAY THROUGH FRIDAY/... VFR conditions are occurring across most of Central PA as of 05Z. Some low clouds have been developing across the west behind the cold front and MVFR ceilings are being observed at BFD. They will likely remain MVFR through the rest of the night. Most guidance suggests that these lower ceilings make it to JST within the next hour or two, though confidence is lower in MVFR ceilings lasting as long as they will at BFD. Not expecting any fog formation tonight as westerly winds stay around 5 to 10 knots and drier air works its way in from the north All TAF sites will likely be VFR by 14z. Northwest winds will gust in the 20-30 kt range through much of the day Mon before diminishing Mon evening. Outlook... Tue...VFR, no sig wx expected. Wed...Restrictions possible in TSRA. Thu...AM SHRA/TSRA with restrictions possible, drying out late. Fri...Mainly VFR. && .CLIMATE... No temperature records were set on Sunday. The following records have been set during this stretch of heat: MDT: * A record high temperature of 99 degrees was set at Harrisburg, PA on Saturday, Jun 22, breaking the old record of 97 degrees set in 1988. IPT: * A record high temperature of 98 degrees was set at Williamsport on Friday June 21st, breaking the old record of 97 degrees set in 1923 and tied in 1933. BFD: * A record high temperature of 89 degrees was tied at Bradford on Friday June 21st, tying the record set in 2022. * A record high temperature of 90 degrees was set at Bradford on Thursday June 20th breaking the old record of 88 degrees set in 2012. * A record high temperature of 88 degrees was set at Bradford on Wednesday June 19, breaking the old record of 87 degrees set in 1987. AOO: * A record high temperature of 96 degrees was set on Saturday, Jun 22, breaking the old record of 91 degrees set in 1988. Highest Max Temperatures for Central Pennsylvania Observing sites for June (date of occurrence is in parentheses: State College 96 in 1952 (26th) and 1933 (29th) Harrisburg 100 in 1966 (27th), 1952 (26th), and 1934 (29th) Williamsport 104 in 1925 (5th) Altoona 97 in 1971 (28th) and 1953 (21st) Bradford 93 in 2022 (22nd) Longest run of consecutive days with max temp >=90 in June: State College 6 (24-29th 1966) /current streak=2/ Harrisburg 10* (19-28th 1943) /current streak=7/ Williamsport 9 (18-26th 1923) /current streak=7/ Altoona 8 (13-20th 1994) /2024 streak=6 (ended Sat)/ Bradford 1 (23rd 2024) /2024 streak=1 (Sat)/ *Harrisburg had a run of 11 days with temperatures greater than 90 degrees that started on 26th and ended on July 6th in 1901. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Fitzgerald NEAR TERM...Fitzgerald SHORT TERM...Fitzgerald LONG TERM...Dangelo/Banghoff AVIATION...Colbert/Bauco CLIMATE...Evans/Steinbugl/Colbert