Area Forecast Discussion
Issued by NWS State College, PA

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037 FXUS61 KCTP 241131 AFDCTP Area Forecast Discussion National Weather Service State College PA 731 AM EDT SUN JUL 24 2016 .SYNOPSIS... Pennsylvania will remain on the northern edge of the subtropical ridge into the upcoming week. A cold front sliding southeast across the state Monday afternoon and evening will bring the best chance of widespread light to moderate rainfall amounts from showers and scattered, potentially strong thunderstorms. However, most of the time today, and again Tuesday through Thursday will be fair, very warm and humid, but rain free. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Variable amounts of high clouds were spilling southeast from the glakes region above an area of surface high pressure, centered over the Alleghenies of western PA. 11z temps ranged from the mid to upr 50s in the north (and perennial cold valleys in central PA), to the mid and upper 60s in the southern valleys. PWATS across nearly all of the CWA are much more comfortable that 24 hours ago, and generally around 0.75 inch, while 1.5 inch PWAT air is not too far south of the PA/MD border (and the PA/Ohio border) along and sw of a surface warm front. This front will buckle to the north and into western Penn late today into tonight, as a weak short wave and 40-50 kt upper jetlet slides east from the Ohio Valley. Partly to mostly sunny skies will occur this afternoon.Mentioned 20-40 pops for a few showers/isolated to scattered tsra (a few of which could be on the strong side) along the front that will be advancing back to the north with decent low-level convergence along it, and a higher cape/EHI environment being advected in from the West and WNW. Highs this afternoon should be 3-4 deg cooler than yesterday in most locations. Maxes will be mainly in the upper 80s across the mountains, but will again soar into the l-m 90s elsewhere throughout Central PA and the Susquehanna River Valley. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/... Mugginess will be on the gradual increase tonight as a warm front drifts back north and brings PWAT values close to 2 inches across much of the state by 12z Monday. A cluster of TSRA likely approaching from eastern Ohio/Western PA was accounted for by 20-40 POPs for now. A few of the storms could still be on the strong side as they drift ESE at around 30 kts (climbing up and over the Allegheny Plateau and encountering the greater llvl moisture/and cape of over 1500 j/kg. && .LONG TERM /MONDAY THROUGH SATURDAY/... Big story in the extended fcst is the expected heat wave lasting into early in the upcoming week, as the axis of the subtropical ridge briefly shifts from the plains to the northeast conus. Anomalous upper lvl ridging building over PA should bring hot and mainly dry wx this weekend, as warm temps aloft suppress convection. Next chance of shra/tsra for most of the area comes Monday ahead of shortwave working across the Great Lakes. However, any rainfall Monday is likely to do little to stem the dry pattern we have been in. Heat indices around 100F appear possible by Monday across the Susq Valley, as higher dewpoints are advected into the area ahead of potential convection. Overnight lows are also a concern as the area doesn`t cool off at night through the weekend with Southern PA lows in the 70s with highest readings Monday morning. Some modest cooling appears likely by Tue/Wed of next week behind weak cold front. However, temps still likely to remain somewhat abv normal within a generally zonal flow. Midweek weather looks dry again, with just low pops for isolated tstms. Fri looks to be the next higher chance for tstm impacts areawide as another cool front progged to move through. && .AVIATION /12Z SUNDAY THROUGH THURSDAY/... Visbys bouncing around at JST/LNS/AOO where it rained yesterday but they should all be VFR in short order as temps heat up sharply. After any fog burns off, the wind will be light and variable today. The high pressure overhead will be attacked as a short-wave trough moves into PA from the NW later today. This forcing could combine with the increase in swrly llvl flow to generate sct SHRA/TSRA late this aftn - but more likely not until this evening - over the west. Have included PROB30 groups for TSRA close to the western terminals starting close to sunset. Otherwise, the scattered nature of the convection will preclude anything worse than a VCSH mention for the last 12 hours of the forecast period. A cold front/weak boundary between two not-too- dissimilar airmasses will across the Great Lakes tonight and through PA on Monday. Thus, additional SHRA/TSRA are expected through Monday evening, and perhaps into very early Tues morning. High pressure returns for mid-week. OUTLOOK... MON...Scattered restrictions possible in SHRA/TSRA. TUE-WED...AM fog poss. Otherwise VFR. THU...Mainly VFR. SCT PM SHRA/TSRA. && .CLIMATE... Record high in both IPT and MDT for today is 96F. Current high temp forecast for both locations is 94F. Considering the maxes of the past few days, the very dry soil and likely lack of thick high clouds today we could easily tie or nudge those records later this afternoon. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Lambert NEAR TERM...Lambert SHORT TERM...Lambert LONG TERM...Lambert/Gartner AVIATION...Dangelo CLIMATE...

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