


Area Forecast Discussion
Issued by NWS State College, PA
Issued by NWS State College, PA
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857 FXUS61 KCTP 182336 AFDCTP Area Forecast Discussion National Weather Service State College PA 736 PM EDT Fri Jul 18 2025 .SYNOPSIS... * A cool night for mid July in store for PA. * More numerous showers/storms possible late Sat through late Sunday as a warm front moves northeast across the region. * A cold front pushes southeast across PA late Sun/Sun night, followed by 2-3 days of dry weather with comfortable, lower humidity. * Another hot and humid spell expected by late next week. && .NEAR TERM /THROUGH SATURDAY/... A few showers over southern PA early this evening will quickly lead to clearing skies overnight. Dewpoints below the 50 degree mark over northern PA now, so looking at a rather cool night for what is normally the hottest week of the summer. Earlier discussion below. The front lingers just South of the border tonight, but drifts slowly northward late tonight and pushes through much of the CWA later Sat afternoon and evening. The main chance for heavier showers and storms will be the far west and south on Saturday, and the return of warm and humid air may hint that the southeast part of the CWA has some heavier downpours late in the day. Thus 2 areas to watch. Warm advection aloft should keep much of the area capped off, preventing most deep convection until later Sat. The srn tier will have the highest PoPs Sat. High temps Saturday will feature a fairly tight range from the upper 70s to mid 80s, based greatly on the amount of cloud cover. && .SHORT TERM /SATURDAY NIGHT/... No real change to this section of the AFD at this point. Earlier discussion below. Saturday night will be warm and muggy in the warm sector as the warm front moves into Eastern PA/Southern NY. PWAT values will climb back up to between 1.5 and 1.8 inches across the bulk of the area. Min temps Saturday night will range from the mid to upper 60s in most places to the low 70s in the larger metro areas throughout the Lower Susq Valley. && .LONG TERM /SUNDAY THROUGH FRIDAY/... Sunday will feature more of a chance of a gusty storm and or a heavy downpour. Outlooks for now are mainly marginal for our area. See the HWO for more information. After the cold front moves across on Sunday, looking at a rather strong shot of cooler air for mid July to work in for Monday into Tuesday. Much lower dewpoints and lots of sun, with a breeze. Unlike the past few weeks, the pattern now supports more of a progressive movement of weather systems. Earlier discussion below. Once again, no significant pattern changes are on the horizon. We`ll continue to see an elongated summertime upper ridge axis from the southwestern Atlantic across roughly the southern half of the CONUS, with an energetic northern stream near the international border with Canada. As for the daily sensible weather, recent medium-range model guidance suggests that a shortwave trough within the above mentioned belt of westerlies will amplify enough later this weekend and early next week to help drive a surface cool front down into the southern Mid-Atlantic. This would allow another refreshing air mass to at least briefly build over the Commonwealth later Sunday and Monday. Prior to that, though, the passage of the cool front itself on Sunday should spark some showers and thunderstorms. Towards the middle of next week, longer range guidance is still suggestive of the southern CONUS upper ridge flexing its muscle, with accompanying height rises for PA signaling a gradual return of heat and humidity, along with increased chances for afternoon/evening focused showers and thunderstorms. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... A wave of low pressure will move along a stalled frontal boundary south of the Maryland border this afternoon and evening and will bring a few hour period of showers to Laurel Highlands and Scent Counties of the state. JST and AOO will have the best chance of seeing rain with less than a 10 percent chance of measurable precipitation NE of a KBFD to KMUI line. KJST will will quickly see a dip into MVFR conditions before midnight tonight as a low stratus deck builds in behind the departing rain showers from this afternoon. KAOO will be similar to KJST. Both locations will dip into at least the IFR range late tonight (though CIGS at KJST should drop below 005 for a 6-8 hour period Saturday morning. The MVFR cloud deck across the SW will likely spread over the Susq Valley this evening through the overnight. Elsewhere across Central and Northern PA (KUNV, KIPT and KBFD), VFR will prevail through much of tonight, but some patchy ground fog could reduce the VSBY to 1-2 miles late tonight (06-11Z Sat). A few showers will continue across the southern half of Pennsylvania tonight as the stalled boundary begins to lift northward as a warm front. Model RH profiles suggest that low clouds and fog will form after ~03Z, with sites west/south of UNV being most likely to see visibility restrictions develop. Outlook... Sat...Mainly dry through Saturday morning, with increasing chances for afternoon/evening showers and thunderstorms. Sun...Numerous showers and thunderstorms anticipated. Mon-Tue...Dry conditions. Wed...Still mainly dry. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Lambert/Dangelo/Martin NEAR TERM...Lambert/Martin SHORT TERM...Lambert/Dangelo/Martin LONG TERM...Jurewicz/Martin AVIATION...Lambert/Bowen