Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 150937 AFDCTP Area Forecast Discussion National Weather Service State College PA 537 AM EDT Tue Jun 15 2021 .SYNOPSIS... A few passing showers or even a brief thunderstorm are expected later this morning and this afternoon as an upper level disturbance drops south-southeast from Lake Ontario and Western New York. The weather pattern will dry out for the Wednesday through Friday period as a large area of high pressure builds southeast and becomes located over the state early Thursday. This weather feature will bring noticeably cooler nights and less humidity. Temperatures will trend warmer into the weekend with showers and storms becoming likely again late Friday into Saturday. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Mid and upper-level trough axis extended from Western new York to the Lower Ohio River Valley early this morning, while mainly clear skies, light wind and llvl moisture from the recent rains of the past few has led to patchy valley fog. The fog will lift into a brief period of bkn stratus between 12-14Z followed by a quick increase in clouds across the northern half of PA with showers advecting SSE into this region in response to diff pva and cooling aloft. Mostly sunny skies will be found across the southern third of the state into this afternoon with perhaps a brief shower during the mid to late afternoon. High temps this afternoon ranging from near 70F across the northern and western mtns, to near 80F in the Lower Susq Valley will be 3-4 F below normal. Greatest QPF will occur across the Mtns North and East of KIPT where 0.10 to 0.15 of an inch is expected. Less than 0.10 of an inch of rain will be common elsewhere. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/... Any convection should fade by sunset along with diurnal cu. Clearing skies and dewpoints in the 40s/50s will make for a relatively cool/refreshing evening and overnight with lows dropping into the mid 40s NW to mid 50s SE. Stream/River-air delta T of around 20F late should promote patchy valley fog again late tonight and early Wednesday. Wednesday should feature abundant sunshine, low humidity, excellent vsby and a 7-10 kt NW breeze wit minor gusts into the low-mid teens. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... Fair and cool weather will continue Thursday, as Canadian high pressure builds in from the Great Lakes. Expect low humidity, mainly clear skies and temperatures averaging a few degrees below average, with Thursday morning potentially quite chilly directly under the surface high. Went below guidance a few degrees. Moderating temperatures are expected by late in the week, as the high passes off the coast and a return southwest flow develops. Increasing model spread/forecast uncertainty noted by next weekend regarding timing of a cold front. The prospects for showers appear relatively high with this feature, given decent moisture return and strong forcing ahead of a deep upper trough. However, will keep POPs close to 50 pct due to timing uncertainty. ECENS and GEFS plumes indicate the best chance of showers/tstorms could be anywhere between Friday evening and Saturday evening. A return to fair and seasonable conditions appears likely Sunday, as high pressure builds in from the Grt Lks. Medium range ensembles then point toward an increasing chance of showers Monday, as tropical moisture streams northward ahead of a deepening upper trough and cold front approaching from the Grt Lks. && .AVIATION /10Z TUESDAY THROUGH SATURDAY/... Most areas have just a few clouds and VFR conditions at sunrise here. Just enough dry air and a breeze above the ground, keeping fog out of most of the area. Still fog at IPT. While most of today will be VFR with dry weather, rather cold air aloft may touch off a few showers later this afternoon. Dry conditions expected for Wednesday into Thursday for a change. Outlook... Wed-Thu...No sig wx expected. Fri...Mainly dry. Perhaps a shower or storm late across the west. Sat...Chance of showers and storms. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Lambert NEAR TERM...Lambert SHORT TERM...Lambert LONG TERM...Fitzgerald/Gartner AVIATION...Martin

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