000 FXUS61 KBGM 171752 AFDBGM Area Forecast Discussion National Weather Service Binghamton NY 152 PM EDT Sat Aug 17 2019 .SYNOPSIS... A persistent storm system will bring warmer temperatures and scattered storms to the region this weekend. The unsettled weather will continue through the middle of next week. && .NEAR TERM /THROUGH SUNDAY/... 930 am Update... Visible satellite imagery shows plenty of insolation for central NY and northeast PA as low clouds and fog from the early morning mix out with the heating. With surface dewpoints in the mid to upper 60s and expected highs into the low 80s most places, mixed layered CAPEs are expected to climb to between 1000 and 2000 J/kg this afternoon. As the diurnal heating commences, a short wave seen on the water vapor imagery in the eastern Great Lakes tracks east and leads to cooling aloft at mid-levels. This added effect is leading to decent instability for our region. Also present is increasing deep vertical wind shear with the approach of the short wave. A belt of mid level winds around 35 to 45 knots or so at 500 mb moves across central NY and northeast PA between 21z and 00z. This leads to 0-6 km wind shear around 40 knots or so in north central NY with around 30-35 knots or so in south central NY and northeast PA. Our expectation is a line of strong to severe storms or bowing line segments with locally damaging winds. The CAMs show some sort of line of storms propagating across central NY and northeast PA between about 18z and 00z. Believe we will have severe storms over much of our forecast area this afternoon so will update HWO and graphical HWO. We are not as concerned with flash flooding as storms will be moving along at a pretty good clip based on the shear profiles. Projected storm motion is about 30 knots or so. Previous discussion... A short wave will pass through NY today. With unstable air in place and bulk shear values around 30 knots, it is likely another round of scattered thunderstorms will develop during the afternoon and continue into the evening. A few thunderstorms will produce heavy downpours and strong wind gusts. A marginal risk for severe thunderstorms exists into the evening hours. Precipitation will taper off overnight. On Sunday, a similar weather setup will be in place with a weak wave enhancing thunderstorm potential in a modestly unstable environment. Temperatures will rise to between 80 and 85 Saturday and to between 83 and 87 on Sunday. && .SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/... 355 AM Update... The combination of heat and humidity will be the main concern in the short term period, which appears to reach its zenith on Monday. Scattered afternoon-evening thunderstorms are also expected to continue. Continued 500mb height rises in west-southwest to zonal flow will occur Sunday night into Monday. That being said, atmosphere still does not become thermally capped, with heat dome/ridge positioned well to our south. We will remain in the belt of westerlies to the north of the ridge, complete with continued shortwaves and thus yet another period with diurnally-driven scattered convection. Deep shear will be enough to again pose a threat for a few cells to contain strong gusts Monday, and the instability offered by the combination of heat and humidity could also lead to locally heavy downpours. Precipitable water values of the atmospheric column get to around 1.5-1.8 inches. GFS-NAM-Canadian models time a shortwave passage with afternoon heating Monday, however, the latest ECMWF is earlier. This presents at least a little uncertainty for exactly how warm it will get, since an earlier wave arrival may hold back heating slightly. Overall odds favor Monday being the peak of the coming warm spell, with high temperatures of upper 80s-lower 90s and dewpoints of upper 60s-lower 70s. If this comes to fruition, Heat Advisories could eventually be needed since the Heat Index would get into the mid to upper 90s at lower elevations. Lows both Sunday night and Monday night, in the muggy environment, will only dip to mid to upper 60s. && .LONG TERM /TUESDAY THROUGH FRIDAY/... 4 AM Update... Warmth and humidity are still expected Tuesday-Wednesday, with continued scattered showers and thunderstorms. Models still depict a cold frontal passage sometime Wednesday afternoon- evening which will especially pose a likelihood for more organized convection, followed by drier and cooler conditions for the remainder of the week. Previous discussion... Tuesday will be similar to Sunday and Monday with diurnal showers and storms and hot/humid conditions. Deep upper low/trough will dig across Ontario and the axis should be centered over the NE U.S by Wednesday night with an associated surface cold front pushing through. Showers and storms are expected with the front Wednesday into Thursday morning...but much drier and cooler conditions should prevail by Thursday night into Friday as strong surface high pressure builds in. Temperatures will still remain near normal and very pleasant...into the upper 70s and lower 80s...behind the front. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... IFR conditions over the next hour at SYR with thunderstorms moving in, then occasional MVFR to IFR conditions will be possible across all terminals through the rest of the afternoon and evening in thunderstorms. Activity largely winds down after 0Z, with mainly VFR conditions through 6Z across all sites. Expect slight reductions in visibility beginning by 9Z with a moist environment in the wake of thunderstorm activity. Looking like mainly MVFR visibility across all sites but ELM - where ceiling and visibility may drop to ALT MIN or even airport min. Conditions gradually improve to VFR after 13Z Sunday, then additional showers and thunderstorms Sunday afternoon may lead to occasional visibility restrictions. Outlook... Sunday night...MVFR conditions possible in lingering showers. Monday to Thursday...Restrictions possible in showers and storms. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...None. NY...None. && $$ SYNOPSIS...DJN/DJP NEAR TERM...DJN/DJP SHORT TERM...MDP LONG TERM...MPK/MDP AVIATION...HLC