558 FXUS61 KBGM 030049 AFDBGM Area Forecast Discussion National Weather Service Binghamton NY 849 PM EDT Sun Sep 2 2018 .SYNOPSIS... A strengthening ridge of high pressure will bring much warmer temperatures to NY and PA beginning Monday, and lasting into Wednesday. Showers and a few thunderstorms are possible each day, mainly in the afternoon and early evening. && .NEAR TERM /THROUGH MONDAY NIGHT/... 830 PM Update...Main updates were to lower PoPs and sky cover this evening. Still cannot rule out some isolated showers and maybe a t'storm redeveloping across the northern Susquehanna region and Mohawk Valley region of Central NY later this evening into the first half of the overnight as a very weak shortwave disturbance moves in. Otherwise, it should remain dry under partly cloudy skies. Patchy valley fog should form later tonight, lingering into Monday morning. Lowered PoPs to just a slight chance across the NY Southern Tier region and Northeast PA...as the upper level ridge will be nearly overhead, providing limited forcing for convective development. Latest CAMs were just showing isolated coverage of showers/storms at best for Monday afternoon...and much of the activity is progged to remain further north...toward the NY Thruway Corridor, which will be more along the periphery of the upper level ridge. Maintained chance PoPs for afternoon showers and t'storms up in this area. Otherwise, it will be hot and humid Monday, with highs ranging from about 85-92 across the region. Peak heat indices will be in the upper 80s to lower 90s in the higher elevation..but 95-101 in the valleys. Left current heat advisories in place, as confidence was fairly high criteria would be met here. Will need to keep a close eye on the valley regions of the NY Southern Tier for possibly meeting heat advisory criteria as well...will let the next shift take one last look at forecast temperature guidance before deciding on this. Monday night should be mainly dry, under partly cloudy skies with patchy fog once again. Perhaps an isolated shower/storm across the far north. Muggy, with lows in the upper 60s to lower 70s. 3 PM update... Skies have finally achieved partial clearing except for the Catskills and Pike County which should soon. Low level instability is good but forcing is weak. The best shear is across the far north where some showers continue this afternoon. A short wave is also in that vicinity which should be east of the area late tonight. With cooling temperatures convection will diminish this evening then be mainly dry late tonight into Monday morning. With the warm moist air, patchy fog will form late tonight. Clouds should fill back in across the Catskills and NEPA. Lows from the mid 60s to the lower 70s. Monday low clouds and fog will clear quickly. Temperatures will rise into the mid and upper 80s. With the high dewpoints, apparent temperatures will be in the 90s. Issued a heat advisory in NY for Yates to Oneida Counties. Cities will be in the upper 90s there. Across south central NY and NEPA, the higher heat will be confined to the urban valleys. Showers and thunderstorms are possible again in the afternoon and evening. Instability best then due to the heating. Some models show a weak short wave and scattered convection forming. Again dying in the evening so the overnight is dry again. Lows around 70. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... For Tuesday, upper level high pressure system builds north across NY and Pa almost through the depth of the troposphere. All 4 main synoptic models and the superblend model guidance strongly suggests at least isolated up to scattered afternoon showers and thunderstorms forming in the upper level high. There is very weak forcing as one would expect but local circulations especially lake induced and elevated heating on our higher terrain certainly could focus isolated storms. CAPEs will be off the charts for our area with mixed layer reaching over 2000 j/kg and surface based CAPES potentially over 3000 J/kg. The wind shear was fairly weak and again larger scale forcing lacking. The model soundings also have some dry air above the mixed layer so we opted for slight chance of showers and thunderstorms Tuesday afternoon which wane Tuesday night with loss of diabatic surface heating. As for the heat Tuesday, guidance suggests maximums will be a tad cooler than Monday but this could be the model's aggressiveness on forming convection. Maximum heat indices barely touch the criteria of 95F in a few spots along the northern Finger Lakes so for now probably won't have an extended heat advisory from Monday into Tuesday. Then for Wednesday, CAPEs values again will be very high well over 2000 J/kg with temperatures and dewpoints leading to heat indices in the mid to upper 90s in the northern Finger Lakes to Syracuse/Utica/Rome so we could see heat advisories again on Wednesday. As for thunderstorms much of the same as Tuesday, upper level ridging and weak forcing will lead to isolated thunderstorms again. Any shower or storm that forms Wednesday falls apart Wednesday night from loss of day's heating. && .LONG TERM /THURSDAY THROUGH SUNDAY/... For Thursday, a cold front drops south from Canada and leads to height falls especially in southeast Canada. This front will bring showers and thunderstorms Thursday into Thursday night. This frontal passage leads to a jet entrance circulation over the northeast U.S which favor low-level frontogenesis and a slowing of the frontal boundary as it reaches the Middle Atlantic States. Meanwhile, a wave will move east along this boundary and potentially lead to a continued period of unsettled into the weekend. Cooler more seasonal temperatures will return for Thursday into the weekend. && .AVIATION /01Z MONDAY THROUGH FRIDAY/... VFR expected to continue this evening and into the early overnight hours before low clouds and fog develop. KELM is expected to see valley fog and drop to IFR between 09-14Z. KBGM may also fall to IFR between 10 and 13z. KITH and KRME should fall to MVFR 07-14Z. Return to VFR after 13-14Z all sites. Mixing will be better late Monday morning with clouds scattering out, but with an afternoon strato-cumulus layer filling in. A few afternoon showers are possible, but not confident enough to add to the latest set of TAFs. South winds tonight will be light. Monday southwest winds at 5 to 10 kts. Outlook... Monday night through Wednesday...Mainly VFR. May see restrictions in showers and storms in the evening. Also, possible restrictions in early morning fog. Thursday through Friday...Restrictions possible in showers and thunderstorms with a cold front. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...None. NY...Heat Advisory from noon to 8 PM EDT Monday for NYZ009-015>018- 036-037. && $$ SYNOPSIS...TAC NEAR TERM...MJM/TAC SHORT TERM...DJN LONG TERM...DJN AVIATION...BJT/TAC