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Area Forecast Discussion
Issued by NWS State College, PA
Issued by NWS State College, PA
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339 FXUS61 KCTP 201720 AFDCTP Area Forecast Discussion National Weather Service State College PA 120 PM EDT Sat Jul 20 2024 .SYNOPSIS... *More humid start to the weekend with a couple of thundershowers *Trending hotter but rain-free and less humid end to the weekend *Seasonably warm with daily opportunities for much-needed rain next week && .NEAR TERM /THROUGH TONIGHT/... Expect isolated to scattered convection to remain confined to the southeast half of CPA or along/southeast of a low level convergence/dewpoint boundary located from near FIG to IPT. Some hints of a weak MCV curl in the MRMS radar loop with area of weakening thundershowers tracking ENE from Huntingdon into Mifflin/Juniata and Perry Counties. A couple of showers/t-storm could linger and be slow to dissipate/shift to the east tonight as indicated by the latest hires ensemble mean/NBM precip fields. High pressure building in tonight should bring clearing skies (from west to east) and light winds to promote fog formation into early Sunday morning. Min temps range from a comfortable 50-55F in the in the NW mtns to a muggy 65-70F in the LSV. && .SHORT TERM /SUNDAY THROUGH TUESDAY/... Fair and warm weather with light wind and moderate humidity is expected Sunday, as surface ridging and associated low-pwat airmass builds across the state. Ensemble mean 850mb temps near 17C supports max temps ranging from the low 80s over the N Mtns, to around 90F across the Susq Valley. Latest HREF indicates a mix of sun and clouds on Sunday afternoon with some fair weather cumulus and a broken deck of cirrus. Clouds will continue to thicken up overnight Sunday night as low temperatures continue their slow upward trend. Lows by Monday morning will be ~5 degrees above normal for this time of year, ranging from the upper 50s in the north to low 70s across the southeast. By daybreak Monday, showers should be on our doorstep ahead of an approaching warm front. Medium range guidance all point to a showery period with high humidity and more clouds than sun for much of next week, as an advancing warm front stalls out in the vicinity of PA. The 500mb pattern features upper ridging off of the East Coast and a persistent trough over the Grt Lks. A deep southwest flow at the interface of these features will import GOMEX moisture northward, interacting with the front to promote multiple days of diurnally enhanced showers/thunderstorms and potentially beneficial rainfall. The southern tier of central PA could really use some rain to lessen the impacts of moderate to severe drought conditions (D1-D2 drought monitor). Ensemble plumes indicate that plenty of cloud cover and more numerous showers/tsra should hold daytime temps to near seasonal norms Monday through the upcoming week. Surging pwats along the frontal boundary should translate to very warm/muggy nights. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... An upper-level trough axis will remain centered over the Great Lakes Wed into Thurs, with unsettled weather continuing for central PA under a continued chc of (mainly aftn/eve) SHRA/TSRA. Southwesterly flow at the sfc and aloft will keep us warm and humid as well. The trough axis should finally swing through by the end of the week, accompanied by a cold frontal passage, which should bring a decrease in PoPs Friday into next weekend. Temperatures look to remain seasonably warm, although humidity should come down following the passage of the front. && .AVIATION /17Z SATURDAY THROUGH WEDNESDAY/... At 15z, considerable high and mid-level cloudiness is overspreading all but far northwestern PA and some cu is beginning to pop up. There is a patch of SHRA (and even a bit of thunder) over the southern Alleghenies (SW of KAOO). Expect scattered showers (and isolated thunder) to continue to pop up with the heat of the day, primarily along and southeast of I-99. Outside of any SHRA/TSRA, VFR conds should prevail. Skies should clear out later this evening into the overnight hours, and winds will diminish. This could aid in the formation of some fog, especially in areas that receive rainfall today. Have not hit the fog hard at any TAF sites yet, but have hints of it at several locations. Sunday should feature predominantly VFR conds, once any fog burns off in the AM. Outlook... Mon-Wed...Patchy early morning fog possible. Otherwise, scattered (mainly aftn/eve) SHRA/TSRA developing with brief restrictions possible. && .CLIMATE... The average temperature from July 1 to July 19 at Harrisburg is 81.2F which is the 4th warmest month-to-date on record (81.3F in 1966, 2012, and 2020). The average temperature from June 1 to July 19 at Harrisburg is 78.1F which is the warmest summer-to-date on record. The average temperature from January 1 to July 19 at Harrisburg is 55.6F which is the warmest year-to-date on record. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Steinbugl NEAR TERM...Steinbugl SHORT TERM...Steinbugl/Fitzgerald/Banghoff LONG TERM...Fitzgerald/Evanego AVIATION...Evanego/NPB CLIMATE...Steinbugl/Banghoff