FXUS61 KCTP 210709 AFDCTP Area Forecast Discussion National Weather Service State College PA 309 AM EDT Sun Jun 21 2026 .WHAT HAS CHANGED... Added gusty wind potential for the convection this afternoon. Now a slight risk of heavy rain and flooding for Monday across the southeast portion of central PA. && .KEY MESSAGES... 1) Brief thundershowers possible this afternoon and evening, with wind gusts over 40 mph possible in some of the thundershowers. 2) Widespread rain on Monday, with severe risk nearby to our south and east. Slight risk of heavy rain and flooding across the southeast portion of central PA. && .DISCUSSION... KEY MESSAGE 1: Brief thundershowers possible this afternoon and evening, with wind gusts over 40 mph possible in some of the thundershowers. Arrival of low amplitude mid/upper trough combined with weak diurnal buoyancy should allow isolated to scattered low-topped convection to develop this afternoon and evening. CAMS show thundershowers developing over the Allegheny Plateau tracking to the east southeast through the evening. Modestly enhanced west-northwest flow and steep low level lapse rates could support a localized strong wind gust (40-45 mph), but the overall magnitude of the threat appears too limited for damaging wind probs/level 1 SPC categorical (marginal) risk at this time. For the majority of central PA it will be a partly to mostly sunny and pleasant start to the weekend with max temps (generally below historical averages) in the upper 60s NW to around 80F in the Lower Susquehanna Valley. Breezy at times also today with wind gusts 20-30 mph from the west/northwest. Winds will diminish tonight with partial clearing and patchy fog into early Sunday morning. Weather conditions for Father's Day look fantastic with astronomical Summer officially starting at 4:24AM Sunday. ------------------------------------------------------------------- KEY MESSAGE 2: Widespread rain on Monday, with severe risk nearby to our south and east. Slight risk for heavy rain and flooding across the southeast portion of central PA. WPC late this afternoon added us into a slight risk of heavy rain and flooding on Monday, mainly across the eastern and southern areas of central PA. The pattern favors heavy rain. Also PW values fcst to be high. The main thing going against much in the way of runoff issues is it has been rather dry across the southeast lately. Also a lot of spread on the track of the low yet. Main area of potential for problems would be the urban centers across the southeast. More information below. A wet start to the work week with widespread rain expected on Monday. The heaviest rainfall is most likely between 8AM and 8PM with storm totals in the 0.75-1.50" range. Current probs off the latest ensembles and National Blend indicate 50-80% probs for >1" across most of central PA. Flooding risk is low with greatest risk likely confined to urban areas where locally heavy or repeat downpours could cause some isolated runoff issues. The higher risk for both flash flooding and severe weather appears to be to the south and east (Maryland and far eastern PA) near the warm front and within the warm sector, so we will need to monitor whether those features trend to the north and west. Rain tapers off/ends Monday night. With high pressure building in behind the departing low, Tue and Wed are likely to be generally dry. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/... VFR conditions will prevail for the vast amount of time through this 06Z TAF cycle, though some impacts from areas of valley fog are possible at a few airfields through about 12-13Z. Included VCFG for several hours at KBFD, KAOO, KUNV and KIPT with prevailing vsbys likely only dipping to around 6SM. or the daylight hours today (and in contrast to Saturday) we will reside under the descending right exit region of an upper level jet into the early/mid afternoon hours with slight height rises ahead of a flat Ohio Valley ridge. As the jet segment shifts to the ENE this afternoon and a few- svrl hundred j/kg of MU CAPE develops after 18Z, the thermally direct branch of the jet (and its rising portion associated with the right entrance region) will lead to some isolated -SHRA across mainly the Ncent Mtns of PA. Any low-topped convection will dissipate early this evening followed by a gradually thickening deck of mid and high clouds later tonight into Monday. Periods of steady light to moderate rain will follow for Monday as much of the CWA stays in the cool stratiform precip regime with sfc low pressure moving out of the Ohio Valley and tracking across Central PA and possibly the Poconos. The SE half of the state should see some instability as fleeting breaks of sunshine develop Monday afternoon. This could result in a small tornado threat as any strong TSRA that form (will move east/NE over a quasi strnry frontal boundary that will extend east from the aforementioned low - across the Scent Mtns and Southern Poconos or Lehigh Valley) could ingest the favorable shear and tilt/stretch it vertically creating some low-topped supercells. Areas of low ceilings and to a lesser degree areas of low visby will impact all central PA airfields to some extent Monday through Monday evening. Outlook... Sun...Showers and thunderstorms after Midnight over the Central and Western portions of the state. Mon...Restrictions likely with a few periods of rain/or showers and thunderstorms. Tue...Lower chances of showers, mainly VFR. Wed...Mainly VFR, watching for precipitation chances though in the evening/overnight. Thu...Restrictions possible in another round of daytime showers. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ WHAT HAS CHANGED...Colbert/Martin KEY MESSAGES...Steinbugl/Colbert/Martin DISCUSSION...Steinbugl/Colbert/Martin AVIATION...Lambert