027 FXUS61 KBGM 160151 AFDBGM AREA FORECAST DISCUSSION National Weather Service Binghamton NY 951 PM EDT Sat Jun 15 2019 .SYNOPSIS... A cold front will usher another round of showers into NY and PA tonight and Sunday. A few thunderstorms are possible from the Twin Tiers southward Sunday afternoon as unstable air works into the region. A frontal boundary will remain near NY and PA for most of the upcoming week with unsettled weather. && .NEAR TERM /THROUGH SUNDAY NIGHT/... 930 PM update...made some more adjustments to POPs, temperatures, sky and wind as precipitation rapidly overspreads NY and northern PA. The mosaic radar imagery shows the remnant of an MCS moving across northwest and north central PA at this time. This feature was encountering much more stable air over northeast PA and central NY. The MCS will get caught up in the advancing upper level short wave which was moving across southeast Ontario into southwest Quebec. Showers will continue to increase for the overnight period as a result. Another MCS over western Ohio and eastern Indiana will eventually follow this first MCS and again encounter more stable air in central NY and northeast PA mainly during the day on Sunday with more showers. The NAMnest is quickest in exiting the precipitation Sunday afternoon with the other hi resolution CAMs models hanging on to precipitation until later in the afternoon. All the CAMs models suggest precipitation all the way to northern NY into the afternoon which is at odds with our current NWS NDFD forecast. This suggests uncertainties as to how far north the precipitation lingers in NY state Sunday afternoon. My gut feeling is that we will be increasing POPs farther north into the early to mid afternoon hours Sunday with the next fresh set of guidance from the 00z balloon launches. 545 PM update...did a quick update to account for more showers in the twin-tier region. Showers were rapidly spreading across western and central NY and northern PA in response to a well- defined upper level short wave moving into the eastern Lakes region. Southwest low-level winds were increasing in response to the arrival of this upper feature increasing moisture transport. Model soundings show a layer of moisture between 850 mb and 600 mb which is sufficient for some light rain showers especially given the divergence aloft. Increased POPs to account for this. Also adjusted temps, winds and sky cover also. 240 PM update... A frontal system moving through the Great Lakes toward NY and PA will bring thickening clouds and an increase in showers this evening and overnight. PWAT values of 1.25 to 1.50 inches are fairly typical of stormy patterns during the summer, and without a threat for thunderstorms, hydro concerns are not forecast. Showers will continue Sunday. A small amount of instability could potentially develop over the far southern forecast area on Sunday afternoon and cause isolated thunderstorms. High temperatures in the lower-70s are forecast. High pressure will briefly build southward Sunday night and bring an end to the rain north of the Southern Tier. A few showers will continue from the Southern Tier southward into PA. Temperatures will fall into the 50s. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... An active period, with multiple waves moving through a moist and unstable westerly flow. Best chance for periods of showers and thunderstorms will be across NE PA and perhaps up into the NY southern tier through the short term period...meanwhile much of this time frame may end up dry further north toward the NY Thruway corridor. Temperatures will be near average with highs in the 70s (near 80 south) and lows in the mid-50s to low 60s. Monday and Monday night: Starting off dry as high pressure noses in from Ontario/New England. Then a shortwave rolls through the Ohio Valley, with a weak surface low reflection moving eastward across southern PA. Instability increase Monday afternoon and evening, mainly south of the NY/PA border. PWATS rise to around 1.5 inches along and south of the NY/PA border and surface dew points rise back into the upper 50s and lower 60s. There are still minor model differences in the exact track and timing of the above mentioned feature, but it seems there will be a good chance for showers and a few thunderstorms again from the NY southern tier south into NE PA late Monday and Monday night...in fact the latest ECMWF actually shows a period of heavier rain moving through during this time. Therefore, went ahead and added some likely PoPs for our southern and eastern zones. Also went close to WPC QPF for this period, which was quite high; a half to three quarters of an inch near Scranton-- Honesdale and Monticello. Tuesday and Tuesday night: Zonal, moist and unstable flow continues as the stalled frontal boundary remains over the region. Additional weak disturbances will likely moves through the area...but tough to time these at this range. Therefore went to high end chance to low end likely far south in NE PA, to lower end chance for the NY southern tier, the mainly dry or slight chance up toward the Thruway corridor of NY. Again, it looks like there could be moderate amounts of instability mainly from the Twin Tiers south so added in chances of thunder here. Wednesday and Wednesday night: A very persistent pattern continues with much of the same into this period. Higher chance PoPs still for NE PA, fading to low chance or slight chance north. It appears there is decent agreement between the latest guidance that the flow will turn a bit more southwesterly out ahead of the next more significant shortwave and low pressure system that looks to potentially impact our area toward Thursday. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... 345 PM UPDATE... Rain chances will increase for Thursday with another surface low moving through the Ohio Valley and towards New England. The best chances for rain will be during the afternoon and evening ahead of the approaching cold front, and with some elevated CAPE and a well- sheared environment, thunderstorms are looking increasingly likely. With precipitable water up to 1-1.5 in during this time, there is a chance for heavy downpours in storms. Chances for showers linger throughout the day Friday behind the exiting system, and while most areas should stay dry Friday night into Saturday morning with high pressure briefly building in, chances for showers will increase again Saturday with another surge of moisture across the region as another surface low developing in the Plains heads towards Lake Superior. Otherwise, little change in temperatures with this forecast update. Highs will generally be in the mid 70s, and lows in the mid/upper 50s. && .AVIATION /02Z SUNDAY THROUGH THURSDAY/... Initially, conditions will be VFR all TAFs as showers move across all terminal sites. This first batch of showers will lead to occasional MVFR restrictions between 00z and 03z/04z all terminals except KAVP where the initial showers arrivae in northeast PA after 03z. We expect occasional restrictions to MVFR in showers at KAVP between 03z and 07z. Between 03z/04z and 10z or so, the NY terminals will drop to MVFR with occasional IFR conditions in visibility. At KRME, KITH and KBGM we expect mainly IFR conditions between 07z and 10z to 15/16z. KBGM and KRME likely will see LIFR conditions around 07z to 12z or so. At KAVP, expect MVFR ceilings most of the day in showers with improving conditions after 20z. An isolated thunderstorm is possible Sunday afternoon near KAVP. Winds will be southwest 8 knots or less initially at most terminals and then variable direction under 10 knots rest of forecast period. Outlook... Sunday night through Thursday...Restrictions with occasional showers. A thunderstorm or two can not be ruled out at some point. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...None. NY...None. && $$ SYNOPSIS...DJN/DJP NEAR TERM...DJN/DJP SHORT TERM...MJM LONG TERM...HLC AVIATION...DJN